Do I need underlayment over subfloor?

Author: Kiel Runolfsdottir MD  |  Last update: Friday, February 21, 2025

If the product you choose doesn't have an attached underlayment, you can almost always install directly over the subfloor without one. But this may result in an unsatisfactory experience. If you want to maximize softness, warmth, moisture protection, and noise reduction, then underlayment is key.

Do you need underlayment on top of a subfloor?

Subfloors are in Good Shape

Well, underlayment is handy for a lot of things, but it's most crucial for stability. Not including houses that are pretty newly developed or were made with exceptionally great materials/attention to detail, most of our subfloors aren't flawless.

Can I put flooring directly on subfloor?

If you're gluing the new flooring to the subfloor, use a sander to remove paint, oil, wax, adhesives, sealers or other material and then thoroughly vacuum off dust and debris. Nail-down or floating floors may be installed over existing vinyl as long as it's no more than two layers thick.

What happens if you don't use underlayment?

Separate Underlayment. Laminate flooring manufacturers typically recommend an underlayment. What happens if you don't put padding under laminate flooring is moisture coming through the subfloor can cause it to warp and mildew. And footsteps on the floor will be louder.

What flooring does not require underlayment?

Underlayment Not Required - Laminate Wood Flooring - The Home Depot.

Subfloor VS. Underlayment Explained

Do I need a vapor barrier between subfloor and underlayment?

Very often, particularly in a below-grade installation on a concrete basement floor, a vapor barrier is recommended in addition to the underlayment. That vapor barrier would go between the subfloor and the underlayment.

Do I need underlayment for vinyl flooring on plywood?

Vinyl flooring can go over a plywood subfloor without a vinyl flooring underlayment as long as the substrate is sturdy, smooth, and flat. If your plywood subfloor is in poor condition, you may need a thin plywood underlayment to smooth the surface out.

How do I know if I need underlayment?

The easiest way to determine if you need underlayment for your new vinyl plank flooring is to look at your current floor. If you're laying the LVP over an existing cushion-backed vinyl floor or a below-grade tile floor, you won't need to use an underlayment.

Can you install vinyl without underlayment?

The best way to find out if you need underlayment for your new vinyl flooring is to look at the planks you're planning on installing. If your planks already have a pad-attached underlayment, you most likely won't need an underlayment.

Can you use plywood instead of underlayment?

Yes, there are different types of plywood underlayment, including: Premium sanded: Because the surface is sanded, it provides for an even and smooth surface. Both RoyOMartin's SmartCore AC Plywood and SmartCore BC Plywood meets underlayment requirements.

What goes on top of a subfloor?

You have the top layer that is your floor covering (Hardwood, Laminate, Vinyl, Carpet, etc.), next you have the underlayment (usually a thin layer of fiber, foam, rubber), below that you have your subfloor (plywood, OSB, concrete), and lastly you have the joists which are the foundation to your floors.

What is quiet walk underlayment?

Description Features & Benefits Technical Features. QuietWalk LV (Luxury Vinyl) is a recycled fiber underlayment that provides excellent support to your flooring. Its dense construction makes it a universal underlayment, suitable for use under many types of floors with a variety of installation methods.

Does all flooring need underlayment?

Flooring underlayment is not always necessary, primarily when you are using a flooring that has its own underlayment padding such as . But underlayment can help with a wide variety of issues, such as sound control in a cement floor application or cold floors in a basement for example.

Is 1/2 plywood ok for subfloor?

Half-Inch Plywood

The most common plywood thickness used as subflooring, half-inch plywood is a solid choice for most homes with standard-width flooring joists. Because of the difficulty and cost to replace subflooring, however, be sure that half-inch plywood is strong enough for your job before installing it.

What is the difference between floor underlayment and subfloor?

Subfloor: Typically made from sturdy materials like plywood, OSB, or concrete, designed to provide long-term durability and support. Underlayment: Made from softer, more flexible materials like foam, cork, or specialized plywood, designed to address specific performance needs.

Can you put vinyl flooring directly on subfloor?

Generally speaking, LVP can be installed directly over subfloors such as concrete or ceramic tile assuming they're clean and level. Additional underlayment may be required if installing over existing hardwood or vinyl sheet floors to protect against moisture damage and sound transmission.

What flooring does not need underlay?

Vinyl – the only flooring that doesn't require underlay
  • It has a cushioned base layer. Long gone are the days of cheap, thin lino rolls that provide zero support or protection. ...
  • It's inherently durable. ...
  • It's designed for direct installation.

What happens if you don't put a moisture barrier under vinyl flooring?

When moisture penetrates your flooring, it can cause mold, mildew, and the potential for water damage. A moisture barrier helps control the water vapor's movement to help protect your floors. Therefore, if you're installing floors in an area that sees moisture, even a little, a vapor barrier is needed.

Can I skip underlayment?

Underlayment is necessary to provide a moisture protection, sound insulation, and a smoother surface for the laminate. Installing laminate directly on the subfloor can lead to noise issues, discomfort, and potential damage from moisture.

Should I put anything in between the subfloor and underlayment?

Very often, particularly in a below-grade installation on a concrete basement floor, a vapor barrier is recommended in addition to the underlayment. That vapor barrier would go between the subfloor and the underlayment.

Does underlayment have to be perfectly flat?

No subfloor is perfectly level, but any signs of unevenness and high or low spots must be remedied. Please follow these requirements: Subfloor unevenness cannot be greater than 3/16 of an inch over a 10-foot span or 1/8 inch over a 6-foot span. Subfloors must not slope more than ½ inch per 6 feet (25 mm per 1.8 m)

What vinyl flooring does not require underlayment?

Underlayment is not required if the vinyl flooring will be laid over a cushion-backed vinyl floor or a tile floor below grade. In all other applications, however, you should use one, such as covering existing hardwood floors, vinyl flooring without cushion, and concrete floors.

How thick should plywood be under vinyl?

Cover the floor area with either a 4mm or 6mm plywood - the thickness selected should be determined by the quality of the surface being covered. Ply should be of suitable quality, eg SP101. Wood should be fixed using screws, twisted shank or ring shank nails, serrated or divergent staples.

Why does my LVP floor crackle when I walk on it?

When you walk on tile, you are pushing it down into the adhesive, and if the tile is not conformed, you are pushing it into contact with the adhesive which causes the clicking/crackling sound. To fix this, you can usually heat the area for at least a day, and then roll the tile using a 100-pound roller.

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