Wall Insulation

Wall Insulation - Works Summer AND Winter!

Most homes built before 1972 do not have insulation in the walls. Also, few homeowners are even aware that their home has empty walls. During the winter, insulated walls will serve to hold the heat in and prevent warmth from escaping. Once insulated, the walls won’t feel ice-cold and condensation/mold is significantly less likely to form. Wall insulation makes a huge difference in the comfort of a home.

During the summer, wall insulation will reduce the amount of heat coming in through the walls and help contain the coolness within your home. The South & West facing walls are often referred to as the “hot walls”, the sun tends to bake on them causing the walls to be hot. These heated walls often tend to radiate heat into the home even well after sundown. Once insulated, the heat entering the home is dramatically reduced.

Wall insulation is usually done when the home is about to be re-painted, re-stuccoed or texture-coated. The reason for this is due to the many holes we must drill on the face of the walls. Wall insulation can not be injected through the attic area nor from underneath the home. We have to drill holes on the face of the wall, from either the exterior or interior.

If you opened the wall, this is how the material would look.

The process involves drilling 2″ holes in each bay, above and below the fire-block. This generally means one hole about 3-feet up the wall and another hole about 6-foot up the wall. These sets of holes are made every 16″ across the wall to access each bay. The walls are then injected with insulation until full. The holes are then plugged with a Styrofoam plug, stucco patching is applied and then each patch is floated to match a standard rough stucco texture.

We can drill from either the interior OR exterior of the home. When working from the interior it is best when the home is vacant, being remodeled or prepared for exposure to dust. Because wall insulation can be a bit dusty, most of our work is done from the exterior.

We provide an exterior stucco patch as part of our process (some companies do not). The texture we can best match is a standard rough finish, typical of most homes. Textures such as a raised Spanish-lace, texture coating or skip-trowel are not finishes we can match very well. We have contractors we refer to deal with this. Our patch typical dries in a day and can be primed & painted soon after. Some homeowners repaint the entire home, others just color-match the paint and paint each patch.

Interior patching involves using a spackle or joint compound. The patching generally looks great when finished, but will tend to shrink and crack as it dries. We only provide a primary application of patching material, additional patching (not provided by us) will be required. The final process of patching involves some sanding, which can also be quite dusty.

We can insulate the walls of a one-story home from either the interior or exterior, but when it comes to two-story homes, we generally need to drill the second-story walls from the interior. The process of drilling holes in stucco involves the use of a large and power drill, it’s rather impractical to work from a conventional ladder. Because of this, we will ask to drill the second-story from the interior. Sometimes we can work on balconies, roofs or patio covers. We deal with each situation on an individual basis.

The attic is by far the most important area of your home to be insulated. Often people are insulating their walls exclusively because they are re-painting or re-finishing the exterior of their homes. We always suggest they also check their attic to make sure it’s adequately insulated. Quite frequently people assure us they have a full 12-inches of material in their attic, but when we arrive at the job they have us check the attic and we discover they have 2-3-inches. The reason we mention this is because wall insulation will help, but if the attic is not done well, you’ll still lose heat in the winter and gain heat in the summer, a well insulated attic is critical.

Exterior wall process:

  1. 2 inch holes are drilled.
  2. holes 3 foot and 6 foot every 16 inches
  3. material is installed and foam plug installed.
  4. stucco patch floated.
  5. stucco is now ready for primer and paint.
1) 2 inch holes are drilled.
2) holes 3 foot and 6 foot every 16 inches
3) material is installed and foam plug installed.
4) stucco patch floated.
5) stucco is now ready for primer and paint.

Not all wall insulation processes are the same!

Long ago, when retro-fit wall insulation was first introduced, all the insulation companies got into it. It was a natural fit. We all bought wall-machines that were roughly the size of two large trash cans put together. These machines were little more than turbo-charged shop-vacs that would blow air into a hose while insulation material was introduced into the air-flow. This worked fairly well except for the inconvenience that every now and then you’d be blowing the wall full of material and then suddenly hear a loud “crack”. Inspecting the inside of the home, you’d discover the wall had actually bulged, cracked or nearly exploded off the framing! The problem with these machines is that they offered one pressure-adjustment. If you set the pressure high, you’d crack, pop or damage walls as they filled. If you set the pressure low your hoses would plug and you wouldn’t fill the wall very well.

In short time installation crews discovered the “happy setting”, a compromise in air pressure where we’d inject the wall with insulation reasonably well without much chance of damaging the wall. This seemed to work well, but the walls really didn’t fill thoroughly. In later years homeowners would remodel and open-up their walls to discover what they thought was settled insulation, it’s wasn’t settled; it was never filled to begin with!

Over time more and more insulation companies lost money on jobs due to damage and the extensive time and labor involved in doing walls. Today, only a small handful of companies still do retro-fit wall insulation. If you call around, you’ll find a lot of companies referring us for wall insulation. The reason we still perform this work is because we innovated a method of insulating walls without fear of damage, and our process actually gets about 35-40% more material into the wall then the old machines did. And let me tell you, 35-40% nearly doubles the effectiveness and especially makes a difference for soundproofing!

I hate to divulge our secret, but we’d rather you understand the process then just take our word for it. When a wall is empty (no insulation in the wall) you have a large cavity where insulation is to be injected. Insulation is injected using air pressure, the insulation is actually being carried by a stream of air going through a hose and into the wall; the air has to go somewhere and it’s force can be strong enough to crack or bulge the wall. When you first start blowing the wall there is a large amount of area for the air to escape, so you can safely apply a good deal of pressure knowing the air can dissipate into the other bays. In fact, in the beginning you really want and need this air pressure to truly drive and force the material into the far reaches of the bay. HOWEVER, as the wall fills with insulation you can actually hear and sense the pressure increasing, and that is where our innovation comes in.

Our truck-mounted (size of a car) machine has a back-pressure bypass relief system that senses the pressure in the wall and safely regulates the pressure such that we won’t bulge, damage or explode the wall. Basically, it’s variable pressure, starting-off high and graduating to lower degrees to finish the wall injection nice and safe. As soon as we perfected this process, we noticed each job was using 35-40% more material. Where was this material going? Into the wall. We’ve even been to jobs where another company broke down and called us to help finish the job before the stucco or paint crew was set to come in the next day. We’re friendly with our competition. We proceed to finish the job in the sections they didn’t do and then go back to the walls they did. Can you guess what happened? Yep, we’re able to inject more material into the holes they considered “done”.


In addition to having an amazing machine, we also drill 2-inch holes. Most other companies are still drilling 1-11/2-inch holes. The larger hole means a more expensive drill-bit and certainly more time drilling and patching, so why do we do it? Well, just like the valves inside your car’s engine, a large opening means we can inject insulation at a thicker rate. If you’ve ever tried to throw a piece of tissue you’ll find it won’t go far, but if you wad it up, it becomes dense and can be thrown some distance. In a similar manner we’ve found a denser material can also carry more inertia and be projected and injected deeper and more thoroughly in the wall cavity. This, along with our variable air-pressure, is entirely why we can get 35-40% more material into a wall. Yes, we’re very proud of our innovation.

Wall insulation is something we charge based on a price per square foot. We deduct for windows, doors, fireplaces and other areas that can not be done. Keeping it simple, we only charge for the area we’re insulating. We drill, fill, plug and patch the holes. Some people just insulate particular walls, perhaps the south and west “hot” walls of the house, while most people insulate the entire exterior perimeter of their home.

When you insulate the exterior walls of your home it’s generally for thermal purposes, to keep the house cooler in the summer and warmer in the winter. You are creating a thermal barrier between the inside of your home and the environment outside your home.

When you insulate walls that are between bedrooms or other rooms of your home, it’s primarily for soundproofing (the reduction of noise between rooms). Because an entire home is either heated or cooled, it doesn’t make sense to insulate interior walls for thermal purposes, but whichever walls customers point to and indicate they want insulated, we’ll do them.

The Common Wall

common wall

The common wall is the wall between your garage and your home. Sometimes this wall, in older homes, is open-framing and can not be insulated using our injection process, but most the time the common wall has drywall, plaster or some material on it. Most homeowners will insulate this wall. It helps contain heat within the home during the winter and also serves to block the heat that develops in the garage from entering the home in the summer. Arguably, the common wall may not make as much a difference as the other exterior walls in your home. Additionally, sometimes there is cabinetry or other obstructions in the way, each homeowner just has to decide for themselves if they want this section of wall done.

Another problem we sometimes run into is when walls already have existing insulation in them. No matter how thin the existing insulation, we cannot inject more insulation into a wall that already has some existing insulation in it. We generally need at least 3″ of depth to inject our insulation. Even if your existing insulation is light & fluffy, we cannot inject more. The best thing to do is check the wall to see if there is existing insulation. See How to Check for Existing Insulation, below.

Estimating the Square Footage for Exterior Wall Insulation

If the square footage of your home is:The square footage of your exterior wall space would be approximately (after taking off 10% for areas we cannot insulate such as windows and doors):

How to Check for Existing Insulation

Quite often homeowners will call us and insist that their walls or ceiling between units must be hollow and they explain that they can hear their neighbor next to them, therefore the wall or ceiling must be empty. Unfortunately, most places built in the 1970’s or newer tend to have fiberglass insulation installed in their walls or ceiling and we can not inject additional insulation into these cavities. The best thing to do is check the wall or ceiling to see if there is existing insulation. There are several methods:

Make a hole. Find a closet or inconspicuous location where a small hole can be made and the inside of the wall or ceiling inspected. You can use a drill bit, knife, screw driver or any sharp object to create an opening the size of a dime. If you have fiberglass insulation it’ll be soft, fluffy and similar to cotton candy. If you can stab a screwdriver into the wall cavity that doesn’t mean it’s hollow, you need to make a hole large enough to see into the cavity.

Another technique is to remove the light switch plate or electrical outlet plate and look to the side of the box. You may have to open-up the plaster or drywall a bit to see to the side of the box, but the plate will safely cover up to 1/2-inch of any area you open-up. To the side of the box the wall will appear either empty or you’ll see a cotton candy-like material.

If you already have insulation in the wall or ceiling, we can not inject additional insulation into that cavity. Your best bet is to then have a drywall contractor install a layer of QuietRock over the wall, this sheet of dense drywall is equivalent to 7 layers of regular drywall and can help stop sound coming through the wall.

For more information on checking for existing insulation please see our video.