Using Spray Foam Insulation in an Old House | REenergizeCO

Is Spray Foam Insulation Right for Existing Homes?

If your home is drafty, if you notice extreme or uneven temperatures when it’s cold or hot outside, and/or if you notice that your energy bill is high month after month, you may have an insulation problem. Degraded or insufficient insulation can affect the comfort and energy efficiency of your home.

For many homeowners, spray foam insulation is an ideal option for making the interior of the house more comfortable and controlling home energy costs. Spray foam insulation is a versatile material with a host of benefits for both new AND older homes.

However, if you have an older home, there are important things to know before you decide to replace current insulation with spray foam:

1. Drywall Must Be Removed

The reason spray foam is such an effective insulator is because it expands to fill in the gaps inside the wall. When the interior of the wall is exposed, this gives spray foam insulation plenty of room to expand and create an airtight seal.

However, if the drywall is still in place, spray foam insulation will not have the room it needs to expand. The foam will push against the inside of the panel, potentially resulting in damage.

When insulating an existing wall with spray foam, it is crucial to remove the drywall first. This will improve the effectiveness of the insulation while mitigating the risk of damage to the wall.

2. Old Insulation Must Be Removed

In addition to removing drywall, it is essential to remove old insulation before installing new spray foam insulation. Spray foam does not bond well with old insulation. When the two types of insulation are mixed, the spray foam will become less effective.

Another concern with leaving old insulation intact when installing spray foam insulation is the risk of moisture building up inside the wall. Over time, this can lead to mold, which is both a health hazard and a threat to the value of your home.

Read More: Can You Add Spray Foam Insulation Yourself?

3. Location, Location, Location

Most homeowners will not have the budget to remove old insulation and install new spray foam insulation in every wall of the house. To get the highest return on your investment without breaking the bank, it is best to be strategic about where you add spray foam insulation.

Some of the parts of your house where spray foam insulation can do the most good include:

The Basement

Unfinished or poorly insulated basements are often chilly and uncomfortable. If this is the case, you may be losing a significant amount of money on energy bills every month due to this one little-used room.

Basement insulation can help you reduce heat loss in this crucial area. In addition, spray foam insulation can prevent moisture from accumulating and serve as a barrier against insects, rodents, and other unwanted pests that can make their way inside through the bottom level of your house.

Crawl Spaces

The crawl space is another frequently overlooked part of the house when it comes to insulation needs. When air leaks form in the foundation of your home, you may experience comfort issues as well as higher energy bills.

The optimal locations for crawl space insulation are along the walls and rim joists. Insulating these areas of the crawl space will close leaks in the foundation, resulting in better air circulation and comfort in multiple areas of your home. You should also see a decrease in what you pay on your electric bill each month.


Depending on when your home was built, you may be surprised to learn that some or all of the walls are probably uninsulated. This issue is especially prevalent in homes built between 1960 and 1979.

As mentioned above, it may not be practical to install spray foam insulation in multiple existing walls. Expanding fiberglass insulation may be a more suitable (and more cost-effective) choice.

Contact an experienced insulation company to find the best option for your home upgrade.

The Attic

Most people who have attics use them for storage and little else. This is unfortunate, as an attic with too little insulation can lead to drafts, make your home too cold or too hot (depending on the season), and cost you on each month’s energy bill.

When it comes to attic insulation, the vertical kneewalls are a suitable place for spray foam insulation. These are the short walls (they rise about knee-high, hence the name) that extend from the floor of the attic to the ceiling that makes up the inside of the pitched roof. However, you will want a different type of insulation for the attic rafters.

Skylight Shafts

A skylight is a wonderful way to let natural light into your home. Unfortunately, skylight shafts with minimal insulation (or no insulation at all) are the rule rather than the exception in existing homes. As a result, the room in which the skylight is located may suffer from extreme differences in temperature from the rest of the house.

The high R-value of spray foam insulation makes it ideal for preventing air leakage in skylight shafts. Spray foam is also moisture-resistant, so choosing it to insulate this area can also protect the joists and other parts of the roof from damaging condensation buildup.

Is Spray Foam Insulation Right for Your Home?

“Old” houses can be upgraded in a number of ways without losing their charm and personality. Given the multiple types of home insulation to choose from, it is important to consider all of your options for improving the comfort and energy efficiency of your home.

An experienced home insulation company can assess the age and condition of your house, advise you of the best materials and optimal areas to upgrade, and handle the installation on your behalf. REenergizeCO has extensive experience helping homeowners in Denver, Fort Collins, and throughout the Colorado Front Range keep their homes comfortable and save on energy.

Please call REenergize at (303) 227-1000 in Denver or (970) 323-3191 in Fort Collins for information on our home insulation services. We identify issues with a comprehensive home energy audit, make targeted recommendations, and perform the installation job with courtesy and professionalism!