How To Insulate Interior Walls In An Existing House

How to Insulate an Old House

For anybody who lives in a place where January temperatures are frequently below freezing, staying in a house with inadequate insulation is a recipe for disaster. That was the situation faced by Christine Flynn and Liz Bagley, owners of the 1916 two-family house that was featured in Season 28 of This Old House, until TOH general contractor Tom Silva came along to help. “People who live in houses built before WWII believe that there is nothing they can do to protect themselves from the cold,” Tom explains.

Interior Wall Insulation in an Old House

Addition of insulation to the walls of a house, if the attic (or roof) is already well insulated, may be the most cost-effective method of lowering heating and cooling expenditures. The fact that many of the house’s walls were going to stay intact, as is the case with most remodeling projects, forced Tom to think about the best way to install the energy-saving material without destroying the whole structure—a process that would have blown the $250,000 renovation budget. His top insulation choice was polyicynene, which is a cream-colored liquid polyurethane that foams up and stiffens after it has been sprayed in place by professionals in areas where walls were left open, such as in newly renovated kitchens and bathrooms and in attic stud bays that had never been covered.

Tom used a slow-pour variant of the foam in the living room and part of the bedrooms.

What is the Best Type of Insulation for Interior Walls?

A homeowner wishing to take advantage of a remodeling to retrofit new or more insulation has a plethora of options, including plastics, fiberglass, shredded paper, even denim scraps and wool, all of which are available in a variety of forms. There are differences in the cost, efficiency (as measured by an R-value, which measures resistance to heat transmission), and amount of skill required to install each kind, of course. So, what is the most effective sort of wall insulation? This is the type of email Andre Desjarlais receives on a daily basis, and he says there is no simple solution to it.

However, depending on the site circumstances and budget, one type of insulation may perform better or may be easier to install than another.

Expanding Foam

This insulation, which is made of either open-cell or closed-cell polyurethane (a plastic) or a specific cement, is applied as soft foam or foamy liquid, filling all gaps and then stiffening once it has been set. It can only be applied by specialists, and it is more expensive than other solutions, but it is the most effective in plugging air leaks. Polyicynene, often known as open-cell polyurethane, is a low-density, spongy foam. It’s sprayed between exposed studs and swells to 100 times its original volume in a matter of seconds after being sprayed.

Closed-cell polyurethane foam expands to 30 times its original volume and hardens to form a highly durable shell when dried.

It is necessary to use mesh across the studs to retain cementitious foam, which applies like shaving cream but hardens over time to a meringue consistency, in order to keep it contained.


Polyicynene provides around R-3.6 per inch of thickness; closed-cell polyurethane provides between R-6 and R-7; and cementitious foam provides approximately R-3.9 per inch of thickness.

Best used

When you have the ability to see beyond the immediate expense to long-term comfort.


Polyicynene has the potential to break existing walls or to leak out and discolor a floor surface. When polyurethane is exposed to ultraviolet radiation, it becomes unstable. Due to the fact that closed-cell polyurethane and cementitious foam are not flexible, gaps may appear between studs as they expand and compress.


If the wall is open, the cost of polyicynene and polyurethane is around $1.50 per square foot, including labor, and $2.25 per square foot if the wall is already in place. Depending on the density, cementitious foam might cost between $1.40 and $2 per square foot. Installers can also use a thin layer of foam to seal leaks, followed by a layer of less costly insulation to complete the job. *Please keep in mind that all pricing are estimates for 1 square foot in a 2×4 wall.


Fluffy blankets that come in large rolls or precut pads that are designed to fit between studs are both options. However, you can also buy ones manufactured from cotton (which is actually shredded denim remnants), mineral wool (which is formed by melting blast furnace slag or rocks such as basalt), and real sheep’s wool.


Fiberglass batts can range from R-3 to R-4.3 per inch of thickness; mineral wool provides around R-3.6 per inch; cotton provides approximately R-3.4 per inch; and wool provides approximately R-3.5 per inch.

Best used

In walls that have been taken down to the studs in a do-it-yourself project.


Insulation must be installed at the full loft height, not compressed. Making insulation less efficient by stuffing it around pipes or leaving gaps in odd-shaped places can reduce its effectiveness. Aside from that, the sharp fibers in fiberglass and mineral wool can hurt the skin, necessitating the use of protective clothing and goggles when working with it. Additionally, some types include a formaldehyde binder, which releases formaldehyde fumes over time. Cotton and wool are natural products that do not have these drawbacks, but they are more expensive and more difficult to come by—especially wool, which is only accessible on the Internet from Canadian wholesalers in some cases.


Uninstalled, basic fiberglass batts cost around 40 cents per square foot, while extra-dense batts cost about $1 per square foot. Mineral wool is around 40 cents per pound, cotton is approximately 60 cents per pound, and wool is the most expensive at $2.75 per pound.

Loose Fill

Dry particles of insulation are blasted into wall cavities through holes ranging in size from 1 to 212 inches in diameter. It may either be installed from the inside of the walls, which necessitates the repair of holes, or from the outside, which necessitates the removal of siding and drilling through the sheathing, increasing the expense of professional installation. There are three main types: fiberglass, which can be treated with formaldehyde (which is produced as a by-product of batt manufacturing) or left untreated; cellulose, which is composed of approximately 80% ground-up newsprint and 20% borate, a mineral added as a fire retardant; and mineral wool, which is composed of approximately 80% ground-up newsprint and 20% borate, a mineral added as a fire retardant.


When permitted to densely fill the space, fiberglass may provide as much as R-4 per inch; cellulose can provide between R-3.6 and R-3.8 per inch; and mineral wool can provide as much as R-2.7 per inch.

Best used

When money is limited, it may be necessary to add more insulation to the attic floor or to install additional insulation inside existing walls.


Cellulose is less expensive to make since it requires less energy, and it is also a more environmentally friendly option in many instances. The use of fiberglass or mineral wool, as opposed to cellulose, may be a preferable choice in damp or windy places, and particularly in buildings with wood siding, because they do not absorb moisture like cellulose does.


When blown in from the inside, cellulose and fiberglass cost around $1.20 per square foot installed; when blown in from the outside, the cost is approximately $2 per square foot installed. Priced uninstalled, they are around one-third of the cost; a homeowner who wishes to conduct a DIY installation can rent a blower for approximately $70 per day.

Sprayed-on Fiber

A type of loose fill that is only suited for stud walls that have not yet been drywalled or plastered, as opposed to other types. A professional installer mixes the same basic insulation materials with water and glue before spraying the mixture between studs with a hose, which helps to guarantee that all of the studs are covered. Furthermore, the glue reduces the likelihood of fibers settling.


Sprayed-on cellulose and fiberglass perform roughly as well as loose fill, while sprayed-on mineral wool performs significantly better than loose fill, providing an R-4.1 per inch greater performance than loose fill. Any spray-on insulation will perform better than loose fill at sealing air leaks.

Best used

Using open walls when you have a limited budget yet want a professional to handle the construction is a good option.


It is necessary to allow the insulation to cure for at least two days before covering it with drywall in order to prevent mildew from developing.


It costs approximately 50% more than loose fill.

Rigid Panels

Foam extruded polystyrene (XPS) or polyisocyanurate (PIC) boards (“iso board”). These panels can be installed on the exterior of a home, above the studs (which are normally a weak point in an insulation system), but beneath the siding, a technique that is particularly efficient in hot, humid regions since the boards act as an excellent vapor barrier as well. In colder areas, the boards can be installed inside the walls, where the moisture barrier will help to prevent warm air from leaving. Tom used to use polyisocyanurate panels in this manner before switching to spray foam insulation: he would build a 2×4 wall, insulate between the studs with batting (with the paper face removed), then cover the entire thing with foil-faced panels and seal them with foil tape before putting up wall board.

The combined R-value of the batts and board on the 2×4 wall was more than the R-value of the batts alone on a 2×6 wall, and he would gain a little amount of additional space in the room as a result of this.


Extruded polystyrene gives about R-5 per inch of thickness. The thermal resistance of foil-faced polyisocyanurate ranges from R-7.2 to R-8 per inch.

Best use

Adding insulation to a 2×4 wall during siding repair or an interior gut project is a common occurrence.


Interior boards must be covered with drywall that is at least 12 inches thick in order to comply with fire regulations. Polystyrene will degrade if exposed to sunlight for an extended period of time, thus it should not be kept out in the sun.


A sheet of 1-inch-thick expanded polystyrene foam measuring 4 by 8 feet costs around $10. A 2-inch-thick panel of foil-faced polyisocyanurate is available for a little less than $30 on the market.

Tom Silva’s Advice on Handling Half-Insulated Walls

“It is necessary to remove any existing insulation in the completed walls of your home if there is insufficient insulation to keep the cold out. This is because the old insulation can get in the way and reduce the efficiency of new insulation. Find out where you need to make improvements by hiring an energy auditor who uses an infrared camera, or by peering in behind electrical outlets or under trim pieces that you carefully remove from your home. You can cut off a horizontal band of drywall or plaster 12 to 16 inches wide and about halfway up the wall if you locate some insulation.

The loose fill or expanding foam may be inserted via the same hole, however you will need to drill additional holes along the top of the wall in order to finish the work.”

Where To Find It

Fiberglass A certainTeed Corp. is based in Valley Forge, Pennsylvania, and can be reached at 610-341-7000. CottonBonded Logic Inc. Chandler, AZ CottonBonded Logic Inc. Chandler, AZ Natural mineral woolRockwool Milton, ON Mineral wool Sheep’s WoolGood Shepherd Wool Insulation Rocky Mountain House, AB, Canada Sheep’s WoolGood Shepherd Wool Insulation Rocky Mountain House, AB, Canada

Loose fill

Cellulose Applegate Insulation Manufacturing Inc. Webberville, MI Applegate Insulation Manufacturing Inc. Nu-Wool Inc. Jenison, Michigan (800) 748-0128 Owens Corning manufactures fiberglass. 419-248-8000 Toledo, OH (Ohio) Fiberglass that has not been treated Johns Manville Corporation Denver, Colorado Mineral Wool is a kind of wool that contains minerals. Delfino Insulation Co., Bohemia, Delfino Insulation Co., Bohemia, NY631-567-45495

Expanding Foam

PolyurethaneIcynene Mississauga, ON, Canada Icynene Mississauga, ON, Canada It is made of cementitious material and is available from AirKrete in Weedsport, New York at 315-834-6609 or at

Rigid foam

Polystyrene that has been extruded Pactiv Corporation Lake Forest, IL Pactiv Corporation Lake Forest, IL Dow Midland, MI Polyisocyanurate Dow Midland, MI Polyisocyanurate Dow Midland, MI Polyisocyanurate Dow Midland, MI Polyisocyanurate Dow Midland, MI Insulation contractors are those that specialize in insulation.

Anderson Insulation Abington, Massachusetts Anderson Insulation Abington, Massachusetts 800-472-1717 Federal Conservation Group Amityville, New York (800) 675-1660 Federal Conservation Group The phone number for SDI Insulation Inc. Contractors in the fields of insulation and drywall Phone: (785-862-0554) Topeka, Kansas Southland Insulators, Inc., Manassas, VA Andre Desjarlais Building Envelopes Program at Oak Ridge National Laboratory in Oak Ridge, Tennessee (865-574-4160 is grateful for his assistance.

Do you require home security for your family? Take a look at our home warranty information.

  • What Is a Home Warranty
  • What Does a Residential Service Contract Cover
  • USAA Home Warranty Review
  • Samsung Appliance Extended Warranty Review
  • Rheem Water Heater Warranty Review
  • What Is a Home Warranty

How to Insulate a House Without Taking Down Drywall

Homeowners are becoming more aware of the need of good insulation as energy bills continue to rise. Some experts believe that by sealing air leaks and installing insulation, a homeowner may save up to 10% on his or her energy cost; however, this will vary depending on the age of the property and its location. Even while older homes, particularly those built before World War II, are often inadequately insulated, practically all homes can benefit from some additional insulation in the future. The specifics may vary depending on the style of property, but there are choices for everyone that do not need pulling away internal wall drywall.

Check Needs

Check with organizations such as the California Energy Commission’s Consumer Energy Center or the North American Insulation Manufacturers Association to determine the amount of insulation that is suggested for your home. Insulation is measured by its R value, which indicates how well it resists heat. The majority of the United States, from California to New Jersey and across the South and Midwest, needs attics to be R38 to R60 and wall cavities to be R13 to R15.


The simplest area to install insulation without harming drywall is in an attic, beneath the roofline of a house or building. It is also in this area that additional insulation is most effective. Addition of loose fill insulation, such as cellulose, rock wool, or fiberglass beads, is one possibility. In construction supply stores, you may purchase these insulations in sacks. Add any loose fill insulation on top of existing loose fill insulation, which was frequently put in older homes; 8 to 12 inches is generally sufficient to fulfill minimal standards in most cases.

See also:  How Much Do Interior French Doors Cost

Batt or Roll

Batt or roll insulation, which may be constructed of fiberglass, cotton, or wool, is another simple alternative for the attic. Every type of insulation has a roughly equivalent R value, although fiberglass is the most popular and is widely accessible at construction supply stores. Fiberglass batts are similar to those that are commonly used in the building of a home wall between the studs. You may install batts or rolls of insulation between ceiling joists or over them, and you can also place them on top of any loose fill insulation that is already in place.

Spray Foam

Spray foam insulation is a relatively new and rapidly growing form of insulation that may be installed without removing walls. This is a polymer substance that is sprayed as a liquid and expands when it comes into contact with air. It has a soft, fluffy look, but it has a high R value despite its low R value. Its most significant advantage is that it expands to cover all holes, ensuring that there are no gaps through which hot air can leave or cold air may enter. The substance is frequently sprayed between the roof rafters to fill the gaps between them, with any extra material being cut away with a knife or a saw in attics.


Cutting holes in the outer siding of existing walls can also be used to add insulation without having to remove the drywall entirely. Using identical tactics, blow either loose fill cellulose or spray foam into walls from the outside of the building. Prepare an opening 1 1/2 to 2 inches in diameter between each pair of studs at the top of the wall and inject cellulose or foam into the cavity with a spray gun using an extension cord.

Replace the cut-outs in the siding, fill with wood filler, sand smooth, and paint to bring the siding back to life.

How to Add Insulation to Walls That Are Closed

Insulation is included in most contemporary houses. Energy-efficient homes are now considered standard practice since they may reduce energy use all year round. However, the walls of older homes built before the 1970s, and even as late as the 1980s, are frequently poorly insulated from the elements. Uncomfortable and expensive energy bills were a result of poorly insulated closed walls. A lack of wall insulation results in an overworked heating or cooling system that works tirelessly to circulate hot or cold air, but is unable to do so because the home envelope is not cooperating.

As a result, permanently connected wallboard must be cut away, drywall screws or nails must be individually removed, R-13 or larger roll insulation must be installed, and new drywall must be hung, finished, and painted.

Is it possible to place insulation behind closed doors and windows?

Injection Foam

Foam insulation has several benefits over fiberglass insulation, the most notable of which is that it is more resistant to mold and mildew than loose-fill, batt, or roll fiberglass insulation. In contrast to blown-in cellulose, its powerful expansion capabilities allow it to push its way into tough spots, such as around cables, boxes, protruding nails and screws, and other areas where gravity-fed cellulose tends to get hung up, such as around electrical outlets. Foam injection insulation is comparable to the individual cans of foam insulation that you can purchase at your local home center, but it is produced on a much bigger and considerably more efficient scale.

When it comes to avoiding wall damage during a retrofit, foam insulation is definitely the best option.

  • Enables workers to reach tough spots that blown-in insulation may otherwise miss
  • Moisture-resistant
  • The injection foam procedure leaves holes in the walls that must be filled, fixed, and painted when they have been completed.


Tissue-based insulation is made from recycled paper and is used to fill the voids of walls and ceilings in homes and buildings. Boric acid is the primary component responsible for its effectiveness. Telephone books, tax forms, and newspapers, all shredded and recycled, contribute to the production of fire-resistant cellulose insulation, which is treated with boric acid for increased fire resistance. It is necessary to drill holes into the inside or outside of each wall cavity in order to inject blow-in cellulose.

It is not suggested that you install blown-in wall insulation on your own.


  • Because of the competition, costs for this form of insulation are kept low. In part due to the fact that cellulose settles, it tends to perform an excellent job of filling in empty areas underneath the insulation over time.
  • It has a tendency to settle, creating hollow areas above the cellulose
  • Wires, boxes, plaster keys, and spider webs are all examples of inner-wall impediments that can be used as hooks. It is necessary to cut holes in the walls.


It is disputed whether or not to retrofit wall insulation since there is no single proper solution for all homes or for all homeowners. Only by doing a cost-benefit analysis in regard to your specific scenario will you be able to arrive at the best decision. At times, the cost of installing insulation may be more than the cost of energy required to heat or cool the building. While uninsulated walls are never a good idea from an environmental aspect, they may occasionally be more cost-effective than the alternative, which is to remove all of the drywall, insulate, reinstall drywall, and paint again.

In recent years, a revolutionary technology known as BIBS has been developed to assist bridge the gap between injected insulation and roll insulation.

On open walls, a fabric sheath or net is connected to the studs, creating a sort of cage that houses blown-in fiberglass insulation (rather than cellulose insulation), which can be in the shape of pellets or other forms.

It is far more effective at preventing air penetration than loose-fill insulation because it makes a tight, thick, seamless blanket, as opposed to loose-fill insulation. Pros

  • It does not come to rest. When you first fill the container, the volume will remain at that level. Certified BIBS materials do not absorb moisture, preventing the formation of mold and mildew.
  • BIBS is a highly specialized system that is not commonly available
  • Nevertheless, it is becoming more readily available. BIBS is not a do-it-yourself method
  • Instead, it is a collaborative effort.


The Blow-In Blanket Technology (BIBS) is a patented system developed by Service Partners LLC that certifies a limited number of insulating materials from various manufacturers for use with the BIBS.

Roll Insulation

Opening up drywall to insert fiberglass or rock wool insulation has many advantages, the most notable of which is its cheaper cost when compared to other methods. Pros

  • Ensures that the greatest amount of wall cavity coverage is achieved in cavities that are not blocked
  • It is rather inexpensive. a do-it-yourself undertaking There are only a few simple tools involved.
  • A mess
  • A labor-intensive process Paint that contains lead might pose a health risk if the walls are coated with lead-based paint.


It is possible that you may need to add insulation to existing inside walls, especially if your home is more than 100 years old. If you have the correct equipment and insulation type, this task may appear to be complex at first appearance, but it is actually rather simple. But what is the most efficient method of accomplishing this? We’ve looked into the solution to this question for you, and we’ll go over it in more detail in this post. Insulating your inside walls using blow-in insulation is the most effective approach to insulate your home’s internal walls without having to remove drywall.

The following are the measures to take while installing insulation behind interior walls: 1.

  1. Determine the location of the wall studs
  2. Drill the insertion holes in the studs
  3. Incorporate the insulation into the wall
  4. Patch up drywall using a drywall knife

Older homes are sometimes prone to chilly drafts and other temperature difficulties, which can result in high energy bills during both the warmer and colder months of the year, depending on the season. This sort of problem may be avoided by installing enough insulation, particularly when it comes to cold drafts. If your internal walls are already in place, continue reading to learn how to install it in that situation.

Steps to Install Insulation Into Established Interior Walls

You’ll need the following items:

  • Large drill bits
  • Blow-in insulation and machine
  • Protective eyewear
  • Worker’s gloves
  • Blow-in insulation
  • Blow-in machine Wall repair kit, trowel or putty knife, cleaning cloth, and stud finder are all required. Masks for ventilation
  • Tarp

1. Locate the wall studs

Make a thorough inspection of the whole wall behind which you intend to put the insulation using your stud finder. Following that, using a piece of chalk or a pencil, indicate the regions where the studs will be spaced apart. In most cases, you’ll notice that there is a gap between each stud in the wall that ranges from 14 and 16 inches in width. It is possible that the space between the windows will be shorter. This stud finder may be purchased on Amazon.

2. Drill the insertion holes

Then, using a stepladder, mark the spots on the wall where you will drill holes for the screws. It is important that these holes are located between studs in the wall, and that they are all at least 8 inches below the ceiling height of the room. In order to guarantee that there are no plumbing or electrical lines going behind your other drill sites, first check behind the first few drill holes to make sure they are not there. It may also be a good idea to turn off the electricity in the room for additional security.

Afterwards, use your drill to make two-inch holes in the drywall in the spots that you’ve outlined with your pencil. You’ll want the holes in the wall to be as high as possible in order for the insulation to naturally pile up and form an equal layer behind the wall once it’s been installed.

3. Feed the insulation into the wall

Take the nozzle of your blower and insert it into the first drill hole, making sure that it is pointing downward. You’ll want the nozzle to extend as far as feasible. – In order to prevent the hole from being accessed, wrap a thick towel or similar large piece of cloth around the hole entrance. While the blower is running, this will prevent insulation from flying out of the hole and damaging the surrounding area. Turn on the blower and move the insulation between the studs while it is being installed.

Maintaining awareness of the fact that a great deal of dust and debris will be stirred up throughout this operation will ensure that you put on your goggles and ventilation mask prior to beginning the process.

4. Do drywall patchwork

After the insulation has been installed in the room’s walls, take your drywall repair kit and go over each hole, using mesh and spackle as necessary to close the holes up. As soon as the spackle has dried, apply primer and paint to the affected areas, making sure that they are uniform in appearance with the surrounding wall. More of a visual learner? If you want to see how it’s done, have a look at this video:

How do you insulate an old house without tearing down walls?

There are a few various approaches you may use to insulate an older home without having to tear down walls. Let us have a look at how.

Insulate the interior walls

When it comes to insulating a historic house without tearing down the walls, the most frequent method is to place insulation beneath the walls themselves. The ideal type of insulation for this is blow-in insulation. It will be necessary to drill holes into the wall and feed the insulation between the joists behind the wall construction in order to do this. If you have some basic carpentry abilities and are familiar working with blow-in insulation, you may complete this chore on your own time.

A contractor may charge anywhere from $400 to more than $800 for this sort of project, depending on the size of the room, the supporting structures underneath the drywall, and the amount of insulation required to complete it.

Double insulate the attic and the roof

It is normal for most homes to lose heat through the attic and roof since heat rises and escapes through these places. As an alternative to insulating your entire home, which may result in concerns such as excessive humidity and structural damage within your walls, you may add an extra layer of insulation to your roof attic for a few hundred dollars instead. The type of insulation you pick will be determined by the amount of existing insulation in your attic as well as the configuration of the space.

Repair exterior brick base

It is common for homes with vinyl siding to have a brick foundation that is around five to six feet high. A crack or gap between bricks can develop over time, creating gaps and holes that allow breezes and water to seep through. This is referred to as “weep holes” in some circles.

It is preferable to have a contractor repair these gaps in order to increase the insulation of your home and keep your energy expenditures down. The cost of repairing the area might range from $250 to more than $500, depending on how much square footage has to be restored.

Seal the windows

It’s also a good idea to inspect all of the windows in your house to make sure they’re not broken. The second most prevalent source of energy loss is through windows. Inspect the seals surrounding your windows on a regular basis to ensure that there are no gaps, holes, or broken frames. If you only have single-pane windows and want to insulate them, window film may be used to achieve the same results as installing double-pane windows. It is possible to insulate your windows even more by placing a thermal curtain or blind covering over them.

See also:  What Is My Interior Decor Style

Seal crawl spaces

It is possible that your first floor has a basement or crawl area beneath it. When possible, inspect the current insulation to determine whether any symptoms of mildew, mold, or moisture have developed in the surrounding area. When it comes to energy loss throughout the year, this might also be a contributing cause to the problem. Overall, when it comes to properly insulating your home, it is preferable to have a strategy in place that is as aggressive as possible.

Can I put insulation over drywall?

Yes, it is possible to lay insulation over drywall. This, on the other hand, is not normally suggested. One of the primary reasons for this is that insulation will make the space appear smaller, and it will almost always need to be covered with some sort of barrier unless you don’t mind having it exposed. You may, on the other hand, think about constructing a fake wall in front of the insulation. However, keep in mind that this will further restrict the available space in the room. If you are determined to insulate a certain wall, consider using other thermal barriers, such as thermal blankets or other materials, in addition to the wall insulation.

Does it make sense to insulate interior walls?

Investing in insulation for your internal walls might make sense if your home is older and you are having major problems with temperature regulation. However, it’s always a good idea to start by considering different types of insulation. In this case, the roof, attic, basement, and windows of the home are all properly insulated. In most cases, these are the locations where energy is lost the most often.

Is it better to insulate walls from the inside or outside?

Generally speaking, it is preferable to insulate the home from the exterior. To do this, it is necessary to ensure that the home’s outside (whether it is made of brick or vinyl) has a strong surface that is free of gaps and fractures.

Wrapping Things Up

We hope you have found this post to be informative and that it has demonstrated how to insulate interior walls without removing drywall. Always remember to check for studs before drilling any holes for your wiring or other installation components. Before you leave, have a look at some of our other posts, including: How to Cool a Bedroom in the Attic Is It True That Vinyl Siding Makes Your House Warmer?

How to Insulate a Wall Without Removing the Drywall

There are several signals that it is time to upgrade your wall insulation, including drafts entering through the outlets and chilly areas. But how can this be accomplished without removing the existing wall coverings? The most terrifying thought you have about this undertaking is that you will have to entirely rip down your walls and start over in order to address these flaws. Fear not, because those walls may remain in their current condition and do not need to be completely dismantled in order to make your house more comfortable.

Because of our extensive knowledge, we know how to insulate your outside walls using injection foam without the need for a comprehensive rebuild.

Most likely, you’re asking how it’s done, and as part of our continued commitment to educate homeowners, we’ll walk you through the process of insulating walls without having to remove drywall.

How to Add Insulation to Walls

When you think about insulating your outside walls, you might imagine how the installation procedure works with classic insulation materials such as fiberglass or certain types of cellulose. In these situations, you would need to either arrange your new insulation around a remodel or just pull everything out and start from scratch. Let’s take a quick look at what that installation looks like from the outside. In order to use fiberglass insulation, the drywall would need to be removed from all of the external walls that you intend to insulate in order to expose the stud cavities.

Installing wet spray cellulose is quite similar to installing dry spray cellulose.


When it comes to foam insulation, if you’re in the middle of a makeover and still want it, you have another option: spray foam insulation.

How to Install Insulation in Walls Without Removing the Drywall

When it comes to insulating walls without removing drywall, injection foam insulation is the answer. It is possible to find various different varieties of injection foam on the market, including the RetroFoam product that we utilize. The use of these materials does not need the removal of existing drywall in your house. The most advantageous aspect of injection foam insulation in this situation is that it may be installed outside, and the installation process is often quick and simple. The procedure of installing siding on your home might vary based on the type of material you have.

Vinyl and Aluminum Siding

A row of siding around the perimeter of the house is removed in order to get access to the sheathing in the case of vinyl or aluminum siding. Afterwards, holes are drilled into each stud cavity, and the foam is injected into each of the holes that have been created. After that, the holes are patched and the siding is reinstalled.

Brick Exterior

Homes with a brick façade go through a somewhat different process than other types of homes. A small hole is drilled into the mortar between the bricks and into each stud cavity, starting at the top of the stud cavity and progressing down to the center and eventually the bottom. This is done to guarantee that the foam fills the whole cavity in the wall entirely. After the foam has been injected, the holes are filled with a standard gray cement that is mixed on-site to provide a consistent finish.

Wood Siding

Wood siding is the most difficult to install and maintain. If the siding can be removed with relative ease, the same procedure as for vinyl and aluminum siding is utilized to remove it. However, if the wood cannot be removed, holes must be drilled in the wood siding to allow the foam to be introduced. Wooden plugs are then utilized to fill in the holes left by the injection of the foam. With all of these siding options, the work may be completed from the outside, resulting in minimal inconvenience for the homeowner.

The only labor required by the homeowner will be the removal of any photographs or knick-knacks from the walls that may have fallen off as a result of the vibrations caused by the drill.

Another Way to Insulate Walls Without Taking Down Drywall

It is not necessary to completely renovate your home in order to install injection foam insulation, but what happens if you don’t want someone drilling into your wood siding and want to avoid this? We haven’t forgotten about you. Installation of injection foam insulation may be done from the inside of your home. In order to complete the installation from the outside, some drilling will be required, resulting in a sloppy situation overall. The good news is that a reputable contractor will ensure that everything in your home is protected and that any damage is cleaned up before they depart your property.

After the installation is complete, the only task remaining for the homeowner is to sand down the dirt and paint over it.

Interested in learning more about foam insulation or perhaps expanding your horizons and learning about spray foam in other areas of your home?

Related Articles

It is not necessary to completely renovate your home in order to install injection foam insulation, but what happens if you don’t want someone drilling into your wood siding and want to avoid that? We haven’t forgotten about you! If you are working from the interior of your home, you can add injection foam insulation. The drilling process has begun, and it is a complete mess, just like it was when the system was first installed from the outside. That said, an experienced contractor will make certain that everything in your home is protected and that they clean up all of their debris before leaving.

It is the homeowner’s responsibility to sand down the mud and paint over it when the installation is complete.

Interested in learning more about foam insulation or perhaps expanding your horizons and learning about spray foam in other areas of your home?

How Is Insulation Installed in Existing Walls?

It’s the task you’ve been putting off for months or maybe years. Your house probably has at least one area where you struggle to maintain comfort, whether it’s scorching hot in the summer or bitterly cold in the winter. You’re aware that adding additional insulation will assist to maintain consistent inside temperatures throughout the year, but you’re concerned about what this could imply for your finished interior walls. What if we told you that you didn’t have to demolish your current walls in order to add new, much-needed insulation?

If your walls are vacant, you may have insulation injected via tiny holes from either the inside or the exterior of the building rather than tearing them down and reapplying drywall.

3 Ways to Insulate Existing Walls

Certain forms of insulation can be injected directly into a wall cavity by drilling a tiny hole ranging from 12″ to 2″ in diameter.

Existing walls are typically insulated with one of three types of materials: cellulose, open cell spray foam, and closed cell spray foam.


It is made from recycled newsprint and is available in a loose fill form that can be blown into existing walls until it is densely packed, also known as dense pack cellulose. Cellulose is made from recycled newsprint and is available in a loose fill form that can be blown into existing walls until it is densely packed, also known as dense pack cellulose Because cellulose can be densely packed and hence provide great heat resistance, we frequently utilize it in retrofit projects. It is possible to retrospectively add new cellulose to a previously insulated wall that already contains cellulose but has settled as a result of weathering.

Another advantage of cellulose is that it is usually treated to be resistant to fire, mold, and pest infestations.

Spray foam

It is made from recycled newsprint and is available in a loose fill form that can be blown into existing walls until it is densely packed, also known as dense pack cellulose. Cellulose is made from recycled newsprint and is available in a loose fill form that can be blown into existing walls until it is densely packed, also known as dense pack. Because cellulose can be densely packed and hence provide great heat resistance, we frequently utilize it in retrofitting projects. In certain cases, new cellulose can be retrospectively applied to an existing cellulose-insulated wall that has settled over time and has to be reinsulated.

The fact that it is often treated to withstand fire, mold, and vermin is another advantage of using cellulose as a construction material.

Don’t Forget about the Attic

Keep in mind that your walls aren’t the only portions of your home that require additional insulation. Attic insulation is perhaps one of the most helpful locations that homeowners in Vermont, New Hampshire, and Massachusetts can improve the efficiency of. Improved general comfort, more energy-efficient heating and cooling, and lower utility costs are all benefits of properly sealing and insulating the attic. With no need to disrupt any drywall, attic insulation is another simple job that you may complete first on your home remodeling to-do list!

Retrofit Insulation Work Is Best Handled by a Professional

Please keep in mind that your walls are not the only portion of your house that need insulation. Attic insulation is perhaps one of the most helpful areas that homeowners in Vermont, New Hampshire, and Massachusetts can improve upon. Proper attic sealing and insulation provides benefits for the entire house, including improved general comfort, more energy-efficient heating and cooling, and lower utility costs.

With no need to disrupt any drywall, attic insulation is another straightforward job that you may complete first on your home remodeling to-do list.

Start enjoying greater home comfort and efficiency — without the mess. Call802-367-3113orcontact usto get a free estimate for your wall insulation project!

Wood has a limited number of adversaries. Whether it’s termites, fire, or a weekend warrior, practically every encounter results in death. However, when it comes to a fourth adversary, water, wood demonstrates remarkable resistance. A piece of wood may become wet again and over again. There’s only one catch: it has to be given the opportunity to dry out before it can be used. German post-and-beam houses were insulated with straw infill and coated with lime-based plaster parging to provide an air seal and a watertight seal.

The presence of water in the walls was almost never a concern.

How to Insulate an Old House

The site of the crime. Homes constructed before the 1950s functioned in a similar manner. With little or no flashing at openings or horizontal outside trim components, the walls were coated in overlapping layers of paper with little or no flashing at the corners. Although the sheathing and wall cavities were frequently soaked, the heat from the dwellings helped the wood to dry out quickly and effectively. Despite the fact that it was wasteful in terms of energy use, it was not harmful to wood walls.

  1. It’s only been since the 1950s or so that this simple wood wall has encountered a new adversary: the search for greater energy efficiency.
  2. In the end, it turns out that this is the worst thing you could possibly do to an ancient house.
  3. Pre-World War II homes have insulation installed between the studs, and this insulation is the single most hazardous component of the wall construction.
  4. Walls that are not properly insulated or sealed dry out because they “breathe.” When you add insulation while doing nothing else to control bulk water, vapor, or ventilation you are effectively breaking the cycle.
  5. is a simple one.
  6. Then, using an absorbent substance such as cellulose, which holds moisture, fill the hollow to ensure that any leaks are not found and that the wall remains wet for a longer period of time.
  7. In no time, and even sooner in a stucco wall, which is fully dependent on the integrity of the drainage layer through which the holes for the insulation were bored, you will notice that the moisture levels in the wall cavities are increasing dramatically.
  8. You’ll very certainly get some excellent capillary condensation activity on the sheathing, frame, and insulation, which will aid in the speeding up of the process even more.
  9. We no longer want any element of a home’s enclosure to be able to breathe these days.
  10. The remainder of the home should be shut up much tighter than a tomb would be required to be.

Then you must replace the windows, install flashing that is properly integrated with the water resistant barrier, and replace the cladding, ideally with a rainscreen. Internally, you must air seal penetrations, repair window millwork, and repaint with vapor-retarding primer before you can move on.

Adding Insulation to Walls

On the site of the crime Construction of homes before to the 1950s was nearly identical. In places where openings or horizontal outside trim components were present, the walls were wrapped with overlapping layers of paper, with little or no flashing. Although the sheathing and wall cavities were frequently soaked, the heat from the dwellings helped the wood to dry very quickly afterward. The wood walls were not destroyed, despite the fact that this was wasteful in terms of energy use. Why are you doing this?

  1. More than that, we frequently went about it in the worst way conceivable: by drilling holes from the outside and blowing in cellulose before filling the holes and painting over it all in the worst way possible.
  2. Assault weapons are used in murders.
  3. The energy-efficiency community may not appreciate hearing this, but physics is science, no matter how much we wish to disagree.
  4. This cycle is broken, however, when you increase insulation while doing nothing else to regulate bulk water, vapor, or airflow.
See also:  How Much To Paint Interior

of the organization is Adding batt insulation is bad enough, but if you really want to put a house out of commission quickly, drill some holes through the cladding, the drainage plane, and the sheathing to completely destroy the wall’s first line of defense and open a path for large amounts of water to flow into the wall cavity.

  • Put your feet up for a moment.
  • A set-back thermostat that lowers the temperature to 65oF at night will help you do the greatest harm, so make sure you do it!
  • Now we’ve got a problem!
  • Homeowners should only be able to breathe through open windows or mechanical ventilation.
  • In order to properly insulate older homes, you must first remove the cladding and weather barrier, drill the sheathing, and then blow or inject loose fill or foam insulation into the cavity.

Internally, you must air seal penetrations, repair window millwork, and repaint with vapor-retarding primer before you can move on.

How to Insulate Interior Walls That Are Already Drywalled

Home-Diy Insulating a wall that has been left open due to new construction or remodeling is a straightforward process. Insulating a completed wall is far more difficult, but it may be worthwhile if your walls lack internal insulation and your heating expenditures are over the sky. if (sources.length) then this.parentNode.removeChild(sources); then this.onerror = null; this.src = fallback; )(,; )(,; )(,; (//$/, “), ‘/public/images/logo-fallback.png’) (//$/, “), ‘/public/images/logo-fallback.png’) ” loading=”lazy”> ” loading=”lazy”> Interior walls that have already been drywalled should be insulated.

To fill the wall with loose insulation, it is preferable to create holes between each stud and use an insulation blower to blast the insulation into the holes.

  • Stud finder with an electronic component
  • A tape measure
  • A pencil
  • A ruler Insulation blower with loose insulation (see the instructions for the quantity of insulation required for your wall)
  • Rented insulation blower with loose insulation Drill
  • For the drill, choose a hole saw bit that is somewhat bigger than the hose on the insulation blower
  • A number of different fabrics
  • Dust masks are recommended. drywall tape with a mesh pattern
  • Joint compound for drywall joints that has been pre-mixed
  • Drywall knife
  • Drywall sandpaper A personal helper


Drop ceilings should be removed, and holes should be made above them, so that you do not have to repaint any of the walls. Alternatively, if your external siding is vinyl and can be readily removed, try removing the strip and blowing insulation into the house from the outside before replacing the siding.


Do not drill holes near electrical fixtures or other potentially dangerous areas.

  1. Use your stud-finder to identify all of the studs in the wall that will be insulated before you begin the insulation process. The distance between the studs will most likely be 16 inches. Make pencil markings 6 inches down from the ceiling, in the center of the space between them. Cut out a circle at each mark with your hole saw. Continue this process all the way across the wall until you have pencil marks between every set of studs
  2. The opening should be somewhat bigger in diameter than the hose on your rental blower, but not much larger. Save each cutout piece, making a mark on the back of each one to indicate which hole it should be inserted into. Don’t forget to put on your dust mask. Load your blower with loose insulation to keep it running smoothly. Insert the hose’s end into the first hole by guiding it in. To keep it sealed, wrap a towel around it. Request that your assistance switch on the machine for you. Continue to hold the hose in place until the insulation is blown into the wall. Once you notice that the insulation is backing up to the hose and the machine is making a higher-pitched noise (similar to that of a clogged vacuum cleaner), instruct your assistant to shut it down. Pull the hose out of the hole and proceed to the next one. The technique should be repeated until all of the areas have been filled with insulation. In order to patch the first hole, stuff additional loose insulation into the hole until it is tightly packed inside. Incorporate your previously-saved circular wall cutout piece back into the hole, allowing the packed insulation to act as a support from behind. Strips of mesh drywall tape should be applied over the cutout piece, covering the circle as well as a few inches of surrounding wall. Spread joint compound over the mesh with a drywall knife to ensure even coverage. Repeat the process for each of the holes, and allow the drywall compound to dry for a full day. Sand it, reapply a second coat, and then sand it again the following day to finish it. Retouch the paint on the wall

The Drip Cap

  • Insulating a wall that has been left open due to new construction or remodeling is a straightforward process. Finished wall insulation is far more difficult, but it may be worthwhile if your walls lack interior insulation and your heating expenditures are over the sky. Cut a circle out of each mark using your hole saw using your hole saw
  • Using loose insulation, fill your blower with air. Wrapping it with a cloth will help to keep it sealed. Instruct your aide to switch on the computer.

How To Insulate Walls Without Removing The Drywall

For the purpose of insulating walls without having to remove the drywall, holes are created on the inside or exterior of the property. Wall cavities are insulated by blowing or spraying insulation materials between the studs of the wall structure. This, together with attic insulation, contributes to the construction of a more energy-efficient home that consumes less natural gas or electricity to maintain a pleasant temperature.

Wall Insulation

When it comes to high energy prices, it has definitely made homeowners much more conscious of the need of having the proper insulation in place. Depending on the location and age of the property, some experts believe that a person may save around 15 percent on their energy cost by sealing up any air leaks and possibly installing some insulation. Even while older homes, particularly those constructed around World War II, are not insulated to current standards, adding insulation to practically any home may be a beneficial investment.

Check Your Needs

In order to determine how much insulation you will require, you could consult organizations such as the North American Insulation Manufacturers Association. Insulation will be graded according to its R value, which measures its resistance to heat. Most of the United States will require attic insulation ranging from R-60 to R-37, and walls ranging from R-16 to R-12 in temperature.

Exterior Walls

By drilling holes into the siding of your house, you may add insulation to your walls without having to remove them. You may insulate the walls by blowing spray foam or cellulose into them from outside.

Simply drill a 1 inch to 2 inch hole between the studs at the top of the wall and then spray the insulation into the hole with a hose to complete the installation. Replace the cuts, fill the gaps with wood filler, sand smooth, and paint the siding to bring it back to its former glory.

Basement Walls

Insulating the basement walls of your home will assist to maintain a more consistent temperature throughout the year in your home. Basement walls can be insulated with a variety of materials, including foam board, spray foam, blown-in insulation, and spray foam insulation. The procedures used to retrofit external wall insulation installation in finished basements with sheetrock insulation are identical to those used in finished basements with sheetrock insulation. Holes are cut to accommodate the installation of the insulation, which are subsequently fixed and painted over.


The most convenient spot for you to install insulation will be in your attic, beneath your roof. Adding insulation will be very advantageous in this situation. Another alternative is to use loose-fill insulation such as fiberglass beads, cellulose, or rock wool to keep the temperature stable. These types of insulation may be purchased in bags at a hardware store or supply store. You can use the loose fill to supplement the existing insulation in older homes that has already been installed.

Roll or Batt

Another alternative for your attic will be roll or batt insulation, which is available in a variety of materials including wool, fiberglass, and cotton. However, fiberglass is far more common and may be acquired at a local supply shop, whereas steel will have similar R values. Fiberglass battis are comparable to those that are used in the building of your home’s walls. Make careful you position the rolls or batts of insulation between the joists in the ceiling or above them, and make sure they are placed on top of any existing insulation.

Spray Foam

Spray foam insulation is a more recent and widely used form of insulation that may be installed without the need to remove your existing walls. If you spray this substance as a liquid, it will expand immediately as it comes into touch with air. However, while having a fluffy and soft look, it will have a high R value. It will expand to cover any gaps or fissures, ensuring that there are no air spaces through which cold air may enter or hot air can depart. In the attic, it is often sprayed between the rafters and the extra material is chopped away with a saw or knife once it has dried completely.

How Blown In Insulation Is Installed Behind Drywall

This procedure, which is referred to as retrofitting, entails making access holes in the wall, blowing in insulation, and then repairing the wall. Some homeowners who have the necessary time and skills can accomplish this themselves, but professional retrofitting is both faster and more successful in most cases. Training and expertise make a significant impact in the overall performance of the new insulation. Insulation may be blown into attics, walls, beneath floors, and even the crawl area of a home to help keep it warm and comfortable.

Step 1. Drill Holes In The Wall

Our professionals locate the studs in your walls in order to install the insulation without removing the drywall altogether. Using a stud finder to mark the studs with a pencil is a good way to save time. During the drilling of 2 inch holes to fill each of these wall cavities, drop cloths are placed on the floors to protect them and make cleanup easier.

The holes are bored as high as possible in order for the insulation to organically pile up and produce an equal layer of insulation on the outside of the house.

Step 2. Blow In The Insulation

When our expert insulation installers work together, they may position the hose in the wall and carefully inch it out while the insulation is blown in tight. This results in the uniformly dispersed, efficient insulation that you require for your wall cavities. Due to the possibility of dirt and dust being stirred up throughout this procedure, our team members are required to wear masks, gloves, and goggles for their own safety and protection.

Step 3. PatchingPainting

After the insulation has been installed in the walls, the holes for the installation are fixed. This can be accomplished by either conserving the drywall discs that were cut when the access points were constructed or by cutting fresh plugs. Apply drywall tape to hold the disc or patch in place while it dries, then cover it with spackle and allow it to dry completely. After all of the holes have been fixed and cured, the next step is to paint the walls to ensure that they are all the same color.

Keep your home cooler in the summer and warmer in the winter without blowing your budget on utilities.

HomeAttic Insulation Service

Barrier Insulation provides retrofitting insulation services for a wide range of commercial and residential facilities. Our staff can assist you with the removal of old insulation and the installation of new insulation in your house, attic, walls, and floors without the need for extensive demolition in order to create more energy efficient dwellings. If you’d like to learn more about how insulation may help you save money while also keeping you more comfortable, please contact 602-499-2922 for additional information.

Leave a Reply

Your email address will not be published.