How to Install Foam Board Insulation to Keep Your Home Warm
Get board to improve the comfort of your home
- Measuring tape
- Circular saw
- Utility knife
- Straightedge
- Level
- Foam insulation boards
- Adhesive
- Furring strips (optional)
- Joint sealing tape (optional)
Are drafts making your home uncomfortable in the winter? Or is it too hot and humid in the summer? Adding insulation can improve your home's comfort level year-round while helping you save on heating and cooling bills. Learn how to install foam board insulation to make your home comfy and cozy throughout the year.
Prepping to Install Foam Board Insulation
Before you get started on your insulation project, you'll want to answer a few questions, such as: Is foam board insulation the right choice? And how much insulation will you need?
Foam board insulation is ideal for areas where other types of insulation, such as batt or blown-in insulation, are not available. It's a good choice for basement areas with concrete walls, but it can also be used in any place where batt or blown-in insulation could be used.
When picking out your insulation, pay close attention to the R-value, which determines how well the material insulates. Cooler areas need a higher R-value. Keep in mind that foam board insulation may not have the R-value you need based on your location.
Finally, remember to measure twice and confirm that you're buying the appropriate amount of insulation. You can always buy more if you don't have enough, but running out mid-project is not ideal.
Correctly installing insulation can be difficult. Health and safety risks are involved; therefore, we highly recommend contacting a pro to ensure the job is completed safely and correctly.
How to Install Foam Board Insulation
Once you've picked out the right type of foam board insulation, it's time to start installing it. Follow these steps to make your home warmer in the winter and cooler in the summer.
Measure and Cut the Boards
Determine what size boards you'll need for your walls. Foam board insulation often comes in 4-by-8-foot boards, meaning you'll most likely need to cut them lengthwise if your home has 8-foot ceilings.
Measure the space between the wall studs to determine the width of the insulation. For example, if your studs are 24 inches apart, you'll need boards that measure 21 inches wide.
Cut the boards using a circular saw or a sharp utility knife. Use a straight edge to guide the blade to ensure a straight line.
Apply the Adhesive
To attach the boards to the wall, apply a layer of construction adhesive to the back. A caulk gun will help you apply the adhesive smoothly and evenly.
Attach the Board to the Walls
Photo: bilanol/ Adobe StockHow you attach the boards to the walls depends on the wall type. If you're installing the insulation in the basement, on a concrete block wall, you'll first need to attach furring strips to the walls, then attach the boards to those strips.
The strips leave a gap between the concrete and the insulation, which is critical for preventing moisture build-up on the boards.
If you're attaching the boards to a wooden wall, you can attach them directly to the surface.
Use a level to ensure the boards are even, then smooth your hands along their surface to firmly attach them.
Seal the Joints
If you need to stack foam board insulation panels next to each other or vertically on top of each other, you'll also need to seal the joints between the panels.
Cut a piece of sealing tape to match the length of the panels, then smooth it between the two, creating a tight seal. Repeat with the remaining panels on the wall.
DIY vs. Hiring a Pro
Looks can be deceiving. Installing foam board insulation can seem like a simple, straightforward project until you get started.
If you've never done any sort of insulation work before or find yourself scratching your head about the right type of insulation to buy or the R-value you'll need, your best bet is to work with a professional insulation company near you. A pro installer can help you pick the right material and ensure that the project is completed the right way the first time.
Frequently Asked Questions
When it comes to fiberglass insulation versus foam board, there are a few notable differences, both aesthetically and functionally. Fiberglass insulation is soft and flexible, meaning it can be squeezed into tight spaces more easily than foam board. Fiberglass insulation also has a higher R-value, making it a better pick for colder climates. However, foam board insulation can resist moisture and pest damage much better than fiberglass.
The average U.S. homeowner pays $1,850 to insulate their home. However, the cost of insulation depends on the type, the size of your home, and who does the installation work.
The cost of foam board insulation depends on whether it's made from expanded polystyrene (EPS) or extruded polystyrene (XPS). EPS has the lower price point, usually costing between $0.25 and $0.50 per board foot, while XPS costs between $0.40 and $0.50 per board foot.
You should remove old insulation before installing new insulation if the old material has been damaged by moisture, pests, or other problems. But if it’s in good condition, you can layer the new insulation over the old. If you decide to remove it, it's best to hire a professional because the material can irritate your skin, lungs, and eyes. Certain types of old insulation may contain asbestos, which can be particularly hazardous to your health and require professional handling.
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