Should You Spray Foam A Basement Ceiling?

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While searching out a way to conserve energy in your home, basement ceiling insulation may be very effective. But, what method should be used? Is spray foam insulation a viable method? We researched to provide you with the answers.

Yes, spray foam insulation is an ideal method because it is much less permeable to water infiltration and air than other insulation solutions. 

Spray foam can be used in many places in your home including the roof, walls, attic, and of course the basement ceiling. Continue reading to learn how to use this technique, the different types available, the pros and cons, and how long it lasts.

Construction Worker Spraying Expandable Foam Insulation Between Wall Studs. Should You Spray Foam A Basement Ceiling

How To Spray Foam Your Basement Ceiling

Spray foam is made from polyurethane. It is applied wet and slowly expands into a thick foam that fits into the tiniest crevice, crack, or gap.

Because this technique is quite demanding, and a little challenging, it would be good to hire a professional. But, if you are up to the task, you might as well follow these basic steps:

  1. Wear your protective gear: The first thing to do is wear your working overalls, gloves, and protective eye gear.
  2. Seal around the rim joists: This is a step that is often skipped, yet it is important to seal around the rim joists before you insulate it because it prevents moisture from seeping in that could lead to rot and other long-term damages. Those tiny cracks that are less than 1/4-inch are best sealed using caulk.
  3. Insulate the rim joists: Apply foam spray in the rim joists that are found near the perimeter of the ceiling. It is the part that comes into contact with the air outside that is more susceptible to air leakage and loss of heat.
  4. Insulate between the joists: Begin from the rim joists on one side and then move to the next, until you complete the whole ceiling. For easy installation, ensure the foam canisters are between 75 and 85 degrees Fahrenheit. This can be done by putting them in a box with a heater throughout the whole process.

Check out this spray foam on Amazon.

Tips For Spray Foam Insulation

Some useful tips to help you successfully insulate are the following:

  • Read the instructions carefully before using.
  • Always wear protective gear.
  • Keep these sprays away from flames because they are highly inflammable.
  • Practice using the hose spray onto something else like newspaper, until you have good control over it.
  • After the spray cures, trim off any excess form that has overfilled in some parts with a knife.
  • If the foam hardens in the straw, trim it until you are able to spray again.

Polyurea Spraying, warming foam coating of roof

What Are The Pros And Cons Of Spray Foam Insulation?

Spray foam insulation can be classified into these types:

  • Closed-cell
  • Open-cell

These sprays have different strengths and weaknesses, but this does not mean that one is better than the other. It all boils down to comprehending their benefits and then choosing the best that suits your needs.

Let us delve into the properties that differentiate the two to provide a better understanding of the pros and cons of spray foam insulation.

Differences Between The Two Types Of Spray Foam

The cell: For open-cell foam, the cells are not fully encapsulated; hence the foam is softer and more flexible. In closed-cell, the cells are fully closed and pressed together preventing air and moisture from penetrating, making them more rigid and stable.

Density: Closed-cell foam is denser than open cell, with a density of 1.75 pounds per cubic foot, while open-cell foam has a density of .5 pounds per cubic foot.

R-value: The R-value dictates how well the foam spray insulates by resisting the flow of heat. Closed-cell foam sprays have high R-values, usually between 6 to 7 per inch, while open-cell foam has values of around 3.5 per inch. These closed-cell foam sprays are excellent in very cold climates.

Expansion: Closed-cell foam spray expands up to 1 inch in thickness after it is sprayed, providing an R-value of 7 with each application. This means you can apply more than once, with each inch providing an extra R-value. Open-cell spray, on the other hand, expands up to 3 inches in thickness, meaning it can only be applied once.

One of the major benefits of this technique is its ability to fill up every small space, providing magnificent insulation. The major drawback would most likely be the high costs.

Let's find out more about the pros and cons of spray foam insulation in the table below:

Pros Cons
Provides a high thermal envelope. The product can be very expensive and installations costs high.
Thermal qualities are excellent. Mostly requires a professional to carry out the job.
Low energy costs. Open-cell is more water porous than closed-cell.
The quality of air in your home is improved. There are suspected health risks.
Contaminants in the air and allergens are kept out of your home.
Closed-cell is especially good in keeping moisture and hence mold out of your home.
Closed-cell reaches even the tiniest of cracks and crevices in the most awkward spaces in your home.
You do not need a vapor barrier.
Can last long up to 80 years.

Technician dressed in a protective white uniform spraying foam insulation

How Long Does Spray Foam Insulation Last?

Basement ceilings normally disintegrate because of uncontrolled moisture but, spray foam counteracts this very well.

It is considered one of the best insulation methods because it completely seals off any air leaks. Its rigidity further makes it non-permeable to water, preventing the growth of mold. These wonderful properties make it insulation that can last a lifetime.

But, it is equally important to note that, if it is not installed correctly, it could lead to deterioration, thereby reducing its lifespan.

What Happens If You Spray Foam Over Mold?

If you are applying to a new basement room or recently repaired basement, there is a high chance there's no mold around, and hence you will be installing it in clean surfaces free of moisture.

But, in case there is mold on the areas being sprayed, it will be killed because its food, namely oxygen and moisture, is cut off. The closed-cell foam works very well to kill off the entire mold.

Open-cell foam, on the other hand, does not prevent mold from forming, because it is permeable to water. It is especially risky to use in cold climates, as moisture can pass through it and accumulate in the ceiling, causing it to rot.

Newly sprayed insulation on ceiling and wall. Should You Spray Foam A Basement Ceiling

In Closing

Insulating your basement ceiling is one of the best decisions when you want to keep your home warm and lower your energy costs. There are several methods to insulate, but one of the best is spray foam insulation. It completely seals off all air leaks and kills all molds if installed properly.

In addition, spray foam insulation has two types: closed-cell foam spray and open-cell foam spray. They are different in terms of their cell formation, R-value, density, and expansion ability. With each having its advantages and disadvantages, one can identify the best to use depending on their needs.

The main advantage of closed-cell spray is that water does not permeate through it because its cells are closed, do not have air in them, and are tightly bound together. Open-cell has air in it and is less dense than closed-cell, hence, it won't add much strength to your ceiling, but it will still create good insulation.

Before you go, check our previous posts on how to drywall a ceiling and find out if insulating a basement ceiling reduces noise:

Should You Drywall Basement Ceiling?

Does Insulating Basement Ceiling Reduce Noise?


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