Tools and Materials

Tools

Circular saws
Pry bar
Hammers
Carpet-cutting knife
Utility knife
Scraper
Putty knife
Vacuum cleaners
Underlayment

Materials

Pressure treated lumber
Nails
Plywood
Vinyl flooring
Tile
Construction adhesive
Detergent
Warm water
Chalk
Vapor tape
Fasteners

Underlayment and Its Common Issues

Foam is generally used as an underlayment. It can be made of polyethylene or polypropylene. It is generally used beneath laminates and floating wood floors. Foam can also be used over concrete subfloor.

However, a vapor barrier film must be used along with it. This film prevents any moisture build-up from concrete. Plywood underlayment is sometimes used beneath hardwood floors.

With time, your foam underlayment can develop some issues.

Rotting: Underlayment might rot when constantly exposed to moisture. It can further lead to growth of mold or mildew.
Compression: Underlayment in high traffic areas may compress more than usual. This can reduce the cushioning effect and cause discomfort while walking.

How to Repair Underlayment

An underlayment can be repaired by replacing the damaged part. Many people ask, “Does underlayment need to be glued down?”. The answer depends on the type of underlayment you are using. In most cases, it is not recommended to glue it down. However, you can do so if the installation instructions permit you to.

Now remove the floor covering of the area you wish to repair. Remove any carpet from the floor. Use a carpet-cutting knife if needed.

Hardwood floor: Loosen the nails with a screwdriver. Lift the baseboards using a pry bar and mallet.
Laminate floor: Cut along the edges of the laminate with a utility knife. Use a pry bar to lift up the planks.
Vinyl flooring: Use a utility knife to cut through the vinyl. It’s best to cut them into parallel strips. Lift the vinyl sheet with a pry bar and roll them off.
Ceramic tile: Remove the grout with a hammer and cold chisel. Put a straightedge across a diagonal. Then, put it across the opposite diagonal to remove the tile. Use a floor scraper to get rid of small tile fragments and adhesive. You can also use sandpaper to remove sticky residue.

Caution

Wear safety glasses when removing any type of flooring. Use a respirator to avoid dust when removing carpet and vinyl flooring.

Now, it's time to remove the underlayment. Follow these ways to remove it:

Removing Soft Underlayment
Peel off the foam or carpet underlayment using a scraper. Remove the stubborn adhesive marks by scraping them with a putty knife.

If it’s not coming off, prepare a soapy solution. Mix one tablespoon of detergent in two cups of warm water. Pour the solution over the padding adhesive. Let it sit for around half an hour. It should scrape off easily now.

Removing Hard Underlayment
Use chalk to mark grid lines across the underlayment. The lines must be at least 18 inches apart. If you want to repair a small section, mark the chalk lines around that specific area.

Carefully measure the thickness of your underlayment. Now set the required depth in the circular saw. This is necessary to ensure you don’t cut the subfloor along with the underlayment.

Now, run the circular saw along the marked chalk lines. You might have to remove some nails or staples along the way. Use a pry bar to remove them.

Caution

Don’t use a soapy solution if you have a wooden subfloor. Water can harm the wood and cause it to expand.

Caution

Wear safety goggles and a dust mask while working with the circular saw.

You can install either soft or hard underlayment. Soft underlayment like foam and felt is well-suited for vinyl flooring.

Hard underlayment refers to plywood, OSB boards and cement board. They are installed beneath laminate, tile or hardwood flooring. However, plywood is the most common choice.

Install Soft Underlayment
Foam and felt underlayment usually comes in a roll. Unpack and roll it out on your floor. Use a utility knife to cut it where required. Cover the whole floor with the underlayment.

Make sure that the rows do not overlap. Secure two rows of foam or felt with underlayment tape.

Install Hard Underlayment
The plywood underlayment has two sides- smooth and rough. Place the plywood panel with the smooth side facing up. Leave a space of at least ⅛ to ¼ inches between the panel and walls. This will allow the wood to expand and contract without developing cracks.

Lay the different rows so that the joints do not line up. Place them just like bricks would be placed while building a wall. Refer to the manufacturer’s manual for the correct nailing schedule. Use fasteners to hold the underlayment panels together.

Install New Flooring
The new underlayment is now ready. Clean up the surface with a broom and remove any debris. You can now install a flooring of your choice over this underlayment.

Caution

Wear safety goggles while working with a hammer.

How to Repair and Replace Damaged Underlayment

Tools and Materials

Tools

Materials

Underlayment and Its Common Issues

How to Repair Underlayment

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