Quck answer
To patch big holes in walls with expanding foam, follow these steps:
1. Clean the hole: Remove any loose debris or dust from the hole using a brush or vacuum cleaner.
2. Prepare the foam: Shake the can of expanding foam well to mix the components. Attach the nozzle and test the flow on a piece of cardboard.
3. Fill the hole: Insert the nozzle into the hole and slowly fill it with expanding foam. Start from the back of the hole and work your way outwards.
4. Allow the foam to expand: Leave the foam to expand and cure according to the instructions on the can. This usually takes a few hours.
5. Trim excess foam: Once the foam has cured, trim any excess using a sharp knife or saw. Sand the surface smooth if necessary.
6. Paint or finish: Finally, paint or finish the patched area to match the surrounding wall.
By following these steps, you can effectively patch big holes in walls using expanding foam.
Repairing small holes in drywall, such as nail holes, can be easily done with spackling compound, while larger holes usually require a drywall patch. However, for mid-sized holes ranging from 1 to 5 inches in diameter, like those made by a doorknob, polyurethane spray foam is one of the most effective materials to use. This foam expands to fill the hole and becomes strong enough to prevent future damage. Closed-cell, low-expansion foam is the strongest and easiest type to work with.
Step 1
Begin by removing any debris from the hole and taking out any remaining pieces of drywall or plaster clinging to the edges.
Step 2
Insert old newspaper into the hole, arranging it at the bottom to provide support for the spray foam. Make sure the area behind the hole remains clear.
Step 3
Shake an aerosol can of spray foam thoroughly and attach the included applicator tube. Spray the foam into the hole, filling it about three-quarters of the way. Allow the foam to expand and bulge out past the wall’s surface.
Step 4
Wait for the foam to fully harden, which may take an hour or two. Then, use a utility knife to cut the foam flush with the wall’s surface and shape it slightly concave.
Step 5
Apply a layer of drywall joint compound onto the hardened foam using a drywall knife. Use the knife to scrape the joint compound flat, let it dry overnight, and then apply a second coat and scrape it again.
Step 6
Once the final coat of joint compound is dry, use 120-grit sandpaper to sand it flat. Prime the patched area with PVA wall primer and then paint it.
