Expanding foam filler isn't a type of insulation. Instead, it's more of a sealant to keep out air, insects and other pests. Foam filler is used to seal gaps, holes and large cracks in a building, especially around the foundation. Per its name, this filler expands as it is applied. Using this product can help make your home more airtight and energy efficient. You don't need any tools, just some time and know-how.
Read and follow the manufacturer's instructions and warnings on the foam filler can.
Put on a pair of safety goggles, work gloves and a respirator or mask. Foam fillers can irritate the skin and respiratory system.
Screw the plastic nozzle extension onto the valve at the top of the can. Shake the can according to the instructions.
Place the end of the nozzle extension about halfway deep into the area you want to fill. Pull the trigger slowly to shoot the expanding foam filler. Fill the area to just below the surrounding surface with the foam because it will expand.
Move the can over to the next empty area once the area you're working in fills up with expanding foam filler. Continue until the entire space is filled. Allow the foam to dry completely -- refer to the manufacturer's directions -- before you sand, trim or paint it.
Use expanding foam filler in a well-ventilated area. Use an old rag to wipe foam spills off while it's still wet. Expanding foam filler is quite sticky.