Do you need to staple down underlay?

Author: Otilia Sanford  |  Last update: Thursday, July 31, 2025

There is no fastening the underlayment to the subfloor. However, during installation some installers like to fasten underlayment to the subfloor to prevent the underlayment from moving. If your choose this route, staples are a good choice to fasten the underlayment.

Are you supposed to staple underlayment?

Fasten the underlayment with either staples or nails. Start on one corner of the panel and fasten the 8' edge first, spacing 2” along the entire edge.

Does underlay get stapled down?

Stick your underlay to your subfloor – use adhesive glue or staples to make sure that your underlay is firmly attached to your subfloor. Lay your carpet on top – Now you can have your carpet fitted on top. Remember that caring for your carpet is the most important way to look after your flooring and your underlay.

Do you have to staple carpet underlay?

Do you need to staple down underlay? To ensure that the underlay is secure and stays in place, you should staple down the underlay or use an adhesive to glue it down into place.

Do you staple or glue underlay?

Use a good spray adhesive to stick the edges down and then go over with a staple gun to secure. If you're dealing with a concrete subfloor, use your adhesive instead. Once laid, tape up any joints using duct tape or similar to prevent the paper from moving or sliding out of place.

HOW TO FASTEN UNDERLAYMENT TO SUBFLOOR

Do you nail or staple underlayment?

Many roofers will tell you that staples are fine for installing the synthetic underlayment. Others will tell you that cap nails are more effective. Both options often depend on the slope of the roof itself. Cap nails are typically made of steel and feature a plastic cap to prevent roof leaks, hence their name.

What is the best way to fasten underlayment?

You can fasten your plywood underlayment using one of the following: galvanized, coated chisel-point staples with a 1/4" maximum crown; galvanized, coated ring shank underlayment nails with a 3/16" diameter head; or flathead wood screws treated with a moisture-resistant coating (such as galvanized or zinc).

Does carpet padding need to be stapled down?

The carpet padding should cover the entire floor you plan to carpet. Use a staple hammer-tacker to fasten the carpet pad along the edge of the tack strip. Trim excess pad at the edge of the tack strip. Staple the carpet pad at the seams, alternating the staples so they aren't next to each other.

Do you glue down carpet underlay?

An underlay is glued to the subfloor. Then, the carpet adhesive should be spread evenly on the back of the underlay. After this, you should neatly lay the carpet onto the adhesive making sure not to leave any bumps or rises in the carpet. You can smooth out any fullness or air bubbles with a glider.

What staples to use for carpet underlay?

19 gauge galvanized carpet staples for flooring and carpet underlayment.

How many staples for underlay?

If you have a hardwood underlayment, like birch (which is typical) just staple that down. On the perimeter of each sheet every 2", in the field every 4".

How do you keep underlay in place?

Each piece of underlay should be laid side by side, with the edges butting up against each other but without overlapping, as this can create an uneven surface for the laminate. Remember to tape the seams together with underlay tape to keep the pieces securely in place and prevent any moisture from seeping through.

Does underlay flatten over time?

Thicker underlay will last better than thinner underlay as it will take longer to flatten down. Underlay will wear down quicker in rooms where there's a higher footfall. Moisture and heat will also have an impact on the life of your underlay.

Should underlayment be screwed or nailed?

Rather than nails, screws are best to use for subfloors — these fasteners are convenient, easy to remove and capable of providing torque that nails lack. Because of their structure, screws can penetrate plywood more easily and improve the connection, whereas nails can weaken the plywood.

Does underlayment need to overlap?

Felt underlayment should overlap the edge metal at the eaves and be overlapped by edge metal on the rakes. This is also true for rubberized asphalt underlayment, but not necessarily true for synthetics. Asphalt-saturated felt may fail for a number of reasons.

Should I glue down underlayment?

No, you should not glue down your underlayment. Underlayment is is a floating material, the same as your laminate flooring. In most cases, you should not glue or nail your underlayment down. You should always check with the installation instructions of the underlayment for proper installation instructions first.

Can you put two layers of underlay under carpet?

Using two or more layers can compromise the stability, performance, and lifespan of your floor, leading to costly repairs and voiding warranties. The best solution is to invest in a high-quality, single layer of underlay tailored to your specific flooring and room requirements.

Is carpet padding usually glued down?

There are two main types of glue down carpet installation. Carpet can be directly glued to the floor, or carpet can be glued to a pad that is itself glued to the floor.

Does the plastic side of carpet padding go down?

To face a carpet pad the right way simply lay the pad so the rubber side is up and the softer side is down.

What kind of staples for carpet padding?

The standard size staples for carpet are the 19-gauge staples.

What can I use to staple down carpet?

Use heavy duty staples a minimum of 1/2″ long. Use no more staples than necessary to securely hold carpet. On hardwood, it may be necessary to tap the staple with a small hammer to drive the staple in fully – do this as you go.

Does underlayment need to be stapled down?

Installers usually lay the underlayment on the floor and start installing the laminate flooring on top. There is no fastening the underlayment to the subfloor. However, during installation some installers like to fasten underlayment to the subfloor to prevent the underlayment from moving.

What is the best fastener for underlayment?

Underlayment screws are specifically designed for fastening wood underlayment to wood subflooring. These screws have an intricate thread pattern that tightly holds the two flooring layers together to prevent squeaking, which is one of their advantages over nails and staples.

How does underlayment stay in place?

Secure rows by taping them together, this will keep your underlayment in place.

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