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How to Insulate an Old House
Amanda Ringler

By: Amanda Ringler on May 1st, 2018

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How to Insulate an Old House

injection foam insulation  |  spray foam insulation  |  cellulose insulation  |  fiberglass insulation  |  existing home insulation  |  older home insulation

If you live in a state that has freezing temperatures in the winter and sweltering heat in the summer, you don’t want to be stuck in an old house with no insulation.

Michigan, and portions of the mid-west and east coast, can have a fluctuation of temperatures in just a week or in some cases just a day. When you’re living in an older home – built in the early 1900s to 1950s – in many cases there is very little or nothing in the attic, walls, or crawl space for insulation.

So how do you insulate an old house?

Find answers to foam insulation FAQ in our learning center.

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RetroFoam of Michigan has more than 15 years of experience insulating homes, and the best return on investment we see are from these older homes with no insulation. Adding an air barrier to an old house won’t just make it more comfortable, it will save you money on your monthly energy bills.

In our continued efforts to educate homeowners, let’s take a look at how to insulate an old house.

What is the Best Way to Insulate an Old House?

When insulating your existing home, no matter the age, the main options will be foam, fiberglass, or cellulose.

The best insulation for an older home that has a lot of drafts is going to be a material that creates an air seal. Spray foam and injection foam are the best options when it comes to making your home energy efficient and comfortable.

Traditional insulation won’t give you the needed air barrier you need to keep your treated air inside and the outside temperatures out where they belong.

RELATED: Foam vs Fiberglass vs Cellulose: Which Insulation is Best for My Existing House?

How to Stop Moisture Problems

Older homes tend to have a lot of cracks and gaps.

Moisture can find its way through these gaps and into your home.

This is why foam insulation is really the best option to really seal up the home from the outside. Foam insulation is the only material that will expand into all of the nooks and crannies to completely fill the cavity.

How to Tell if You Need Insulation

Do you have high monthly energy bills, uncomfortable rooms, problems with moisture, mold, and mildew?

These are just some of the signs you need insulation in your home. Other symptoms include a constantly running furnace or air conditioner, cold floors, drafts, and walls that are cold to the touch.

If you have some insulation in your home, it is likely if it hasn’t been replaced or maintained in at least 20 years that the insulation has shifted, settled, sagged, and in some cases deteriorated.

700x468_BlownInsulation_jpgWhat Happens to Existing Insulation in the Attic, Walls, and Crawl Space?

If your older home happens to have existing insulation, in some cases it will need to be removed and in others it will stay where it is.

Let’s talk about the crawl space and the attic first.

If the traditional insulation in these areas has become wet, then it will need to be removed due to mold and mildew issues. You will be able to tell as it will look wet and possibly have black spots throughout as the mold grows.

Over time cellulose and fiberglass will shift, settle, and sag. If that’s the case you can add more insulation, but you’ll have to make sure you maintain the cellulose with raking and ensure the fiberglass is properly cut and installed.

When it comes to the walls of your home, you can add more insulation while leaving the original intact. If you want to add insulation without tearing down your drywall, you can use blown-in materials.

If you want an energy efficiency, comfort, and an air barrier, foam insulation is the best option.

When installing spray foam insulation in the attic and crawl space, the old insulation will need to be removed. This also includes the rim joist. This way the spray foam can work properly and seal off the attic, which will make your home energy efficient. Sealing off the crawl space will make you more comfortable by eliminating those cold floors and the rim joist to eliminate drafts.

The existing insulation in your walls doesn’t need to be removed when installing injection foam. That’s because the injection foam compresses that existing insulation to completely fill and air seal the stud cavity.

Insulating an Old House: Process and Areas to Install

When it comes to installing foam insulation in your older home, you should insulate from the very top all the way to the bottom.

This method seals the entire envelope of the home and includes the attic, walls, rim joist, and crawl space. If you want to eliminate air leakage in your home, it doesn’t make sense to leave any area uninsulated.

Now let’s talk about the installation process.

RELATED: What are the Best Places to Insulate Your Home?

680x300_RFM_AtticSprayInsulationInsulating the Attic

Typically, older homes have a larger attic space, which may seem easy to install because there is more room to work, but there are gaps to worry about.

There will be gaps in the roof deck and by the soffits. Any time you have gaps, even if it’s only a half-inch, that is a space the foam will get into.

There is an easy fix, the installation crew will take more time to find those gaps and either use a can foam to seal them or use plastic the off to avoid the spray foam getting into places where it shouldn’t be.

RFM_InjectionCloseUp_jpgInsulating Walls in an Old House

The walls in an old house can add some complications to the install process, but it’s nothing we can’t handle.

Almost every old house has double and triple studs. So, when crews take the siding off and drill into the house. The double and triple studs just add extra drilling time for the crews to ensure the job is done correctly.

Another thing crews find with older homes are a lot of nails. Because they use an auger-style bit which grinds the wood out, when that bit hits a nail it stops. When crews know they are working on an older home, they make sure to bring extra drills.

The process of insulating the exterior walls of an older home or a newer home is basically the same, aside from the things we just discussed.

The type of siding your home has can change the installation process from the technique used to the amount of time it takes to complete the job. We work with vinyl, aluminum, brick, wood, as well as slate tiles and stucco.

The injection foam insulation can be installed in your exterior walls from the outside, so you don’t have to worry about taking down any drywall.

Crawl Space and Rim Joist Insulation

One thing that stands out in older homes is the crawl space is usually what’s referred to as a Michigan crawl space or a Michigan basement.

This refers to a crawl space or basement that has stone walls. Sometimes there is a dirt floor or concrete and the walls are shorter – around 5-feet-tall.

These stone walls can be sprayed with foam insulation just like any other surface to create an air seal.

Learn More About Foam Insulation

For owners of older homes it is important to keep the character of their old home while brining the comfort level and energy efficiency into the 21st century with the right insulation.

If you want to learn more about the benefits of foam insulation, check out the Learning Center on our website.

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About Amanda Ringler

Amanda previously has worked as a breaking news and crime reporter, TV news producer, and editor in Flint and Detroit. Throughout her career as a journalist, she has won several awards from the The Society of Professional Journalists - Detroit Chapter and the Michigan Press Association. As part of the RetroFoam of Michigan family, Amanda uses her experience as a journalist to write content that will help educate homeowners on the benefits of foam insulation. When Amanda isn’t writing, she’s spending time with her husband and rescued huskies. She also loves knitting, making art, cooking, and hosting dinner and a movie night for friends and family.