How To Install Foam Board Insulation?

Foam board insulation consists of sheets of foam typically measuring 4 feet by 8 feet, with a thickness ranging from 0.5 to 2 inches. These sheets serve the purpose of insulating walls.

 

Mastering the skill of installing foam board insulation is a valuable asset for any DIY enthusiast. These lightweight boards find versatile applications throughout the home, particularly in basement walls. This post aims to guide you through the process of installing foam board insulation, providing clear and efficient instructions for a successful installation.

 

What is Foam Board Insulation?

 

Foam board insulation consists of sheets of foam typically measuring 4 feet by 8 feet, with a thickness ranging from 0.5 to 2 inches. These sheets serve the purpose of insulating walls.

 

Closed-cell foam boards exhibit impressive strength and durability, capable of withstanding pressure. Unlike fiberglass, another effective insulator, foam boards demonstrate high resistance to moisture, making them particularly suitable for basement applications.

 

Two primary types of thermal insulation boards for walls are EPS (expanded polystyrene) and XPS (extruded polystyrene). When insulating basements, foam board insulation is preferred over fiberglass insulation due to its moisture-resistant properties.

 

 

Where Do You Need Foam Board Insulation?

 

Foam board insulation is versatile and can be employed in various applications where other insulation types, such as batts, spray foam, and attic insulation, are commonly used. It is particularly effective in scenarios where preventing moisture exposure is crucial. However, it may not be the most suitable choice for spaces with limited room and is not recommended for insulating heated basements.

 

This is due to the fact that other materials offer higher R-value per inch in such applications. Optimal uses for foam board insulation include vaulted ceilings, insulated floors, and exterior walls, where its benefits shine.

 

Things You Need For Foam Board Insulation

 

Before embarking on your project, begin by selecting the appropriate type of foam board insulation. Familiarize yourself with the distinctions between EPS and XPS foam boards. Additionally, choose the suitable type of wallboard insulation for your needs. Before commencing work with foam board insulation, ensure you have the following tools ready:

 

1. Utility knife

2. Straightedge

3. Measuring tape

4. Marker

5. Framing square

 

How To Install Foam Board Insulation On Surface Mount Interior Walls

 

Step 1: Measure and Cut Insulation Boards

 

Begin by determining the quantity of wallboard insulation required for your project, utilizing a tape measure. Commonly available in 4-foot by 8-foot sheets (32 square feet), these sheets are suitable for an 8-foot high wall without requiring trimming. However, for walls of varying heights, multiple boards may be needed.

 

Note that wall studs are typically spaced at intervals of 12, 16, or 24 inches. Therefore, trimming the boards is generally required only lengthwise, ensuring that the edge of each sheet aligns with a stud. For irregularly shaped walls, a sharp knife is used to trim each sheet.

 

To cut styrofoam insulation, use a sharp blade to cut at an aggressive angle straight through the styrofoam insulation panels.

 

Step 2: Hang the Rightly Sized Boards

 

To hang foam core on the wall, you have two options: use construction adhesive or button cap nails. In most cases, construction adhesive is the more convenient choice.

 

Ensure correct spacing to align with the studs; otherwise, the board won't fit securely. Also, ensure that sheets placed side by side are connected to the same stud, providing lateral strength to the wall.

 

Given that drywall is typically installed horizontally, it's advisable to install foam boards vertically. Installing both the boards and drywall in the same direction may lead to unwanted cracks or intersections later on.

 

Step 3: Apply Joint Tape over the Joints

 

Consider sealing the joints with joint tape, although this step may be optional depending on the nature of your project.

 

Installing Foam Board Insulation Inside the Wall

 

If your walls exceed the typical 2" x 4" dimensions, it becomes necessary to install foam board insulation inside the wall. Thicker walls are crucial for meeting the building code-recommended R-value.

 

Begin by identifying the spacing between the studs. For 2x6" walls, the studs are typically spaced at 16" or 24" centers. Measure from the inside to inside, not outside to outside.

 

For instance, if the studs are on 24" centers, the width of your foam board should be 21", corresponding to the space between those studs. Depending on your project's requirements, you might need to use construction adhesive to bond multiple layers of foam sheets together. Alternatively, specially designed interior wall insulation panels can also be employed.

 

Installing Foam Board Insulation on Cement or Masonry Block Walls

 

Step 1: Choose a Method

 

Regardless of whether you're installing foam boards on a stud wall or block wall, the measuring process remains the same. However, when attaching foam board insulation to concrete, the approach differs. Begin by affixing furring strips to the wall and then attach the foam boards to these strips.

 

When pondering how to attach foam board to concrete, avoid direct gluing to the block. Optimal insulation occurs when there's an air gap between the board and the wall. The fundamental procedure is consistent, whether you're installing foam board insulation in the attic or any other area of your home.

 

Step 2: Install the Furring Strips

 

Professional installers use masonry nails and a pneumatic nail gun for furring strip installation. Like wall studs, place the furring strips at consistent intervals, covering the area from the floor to the ceiling.

 

Ideally, utilize construction adhesive to install furring strips over foam boards. Alternatively, nails can be used. Ensure there's a 3/4" gap between the foam board and the block wall. This gap serves as a protective measure, keeping the foam unaffected even if moisture emanates from the block. The insulation performs optimally with a slight gap between the foam and the wall.

 

FAQ: About Installing Foam Board Insulation

 

What is R-value?

R-value signifies the efficiency of insulation. A higher R-value indicates greater heat resistance. Expanded Polystyrene (EPS) boasts the highest insulative capabilities compared to other materials.

 

Can I install foam board insulation by myself?

Yes, the process is relatively straightforward. You only need to cut the foam boards and install them using a few readily available tools.

 

How do you cut foam insulation?

Use a utility knife and make steady cuts in the foam. To facilitate a smooth process, create a cutting line before actually cutting the foam board. Segmented utility knives, also known as box cutters, are easily accessible and useful for this task.

 

Is it necessary to seal joints in foam board insulation?

Yes, the joints of foam boards should not align. There should be gaps between the boards to prevent thermal bonding.

 

What finishing materials are used with foam board insulation?

Drywall is the most commonly used finishing material. However, other materials such as mortar, wood, and vinyl are compatible with EPS and XPS foam boards.

 

What is the purpose of foam insulation?

Foam insulation is used for thermal resistance. It serves to prevent the infiltration of moisture, making it effective for keeping areas dry.