Do I Need Underlay Under Laminate or Vinyl Plank, and Which One for a Basement?

Underlay (also called underlayment, underpad or membrane) is the thin roll you lay on the subfloor before the planks. It cushions the floor and cuts noise, and some types also block moisture coming up from below. Here is how to tell if your floor needs one and which one to pick, with real products sold on FloorBox.

You can see every model in our laminate and hardwood underlayment category and our vinyl underlayment category.

Does laminate need underlay?

Yes, unless the planks already have a pad attached. The quick way to check is the Underpad Attached line in the product page specifications.

• Underpad Attached: No. You need a separate underlay. The Planchers 1867 Authentic Advanced laminate is one example. The Kronotex install guide attached to its product page has you lay an impact sound underlay before the planks and, over a screed (a poured cement-type subfloor), a vapour barrier first.
• Underpad Attached: Yes. The pad is built into each plank. The Centura Studio laminate, for example, has a 2 mm Silent Pad attached under each plank (Centura data sheet attached to the product page).

Some underlays say clearly that they are made for planks without a pad. The Biyork Eco Quiet EVA underlay is one: Biyork made it for laminate and floating floors without pre-attached pads.

Thinking about how thick your laminate should be? See how to choose laminate thickness and AC rating.

Does vinyl plank need underlay?

Many click vinyl planks come with the pad already attached. We explain how they work in how click vinyl flooring locks together.

• Pad attached: the Torlys RigidWood Firm vinyl plank has a built-in FoamPlus Blue underlay. Torlys's install guide says no additional underlayment is required.
• No pad attached: pick an underlay made for vinyl. On the product page, look for Use For: Vinyl, or a vinyl underlay like these:

AcoustiTECH LV vinyl acoustic underlayment

• 2.1 mm thick, for floating vinyl only. AcoustiTECH says it should never be glued down.
• The planks need a click joint and must meet AcoustiTECH's minimum plank thickness. Check the current data sheet for the number.
• It can go under planks that already have a thin pad, if that pad is 1.5 mm (1/16 inch) or less, per the AcoustiTECH data sheet.

Goodfellow Red UHD vinyl underlayment

• 1.5 mm EVA foam with a 0.10 mm red vapour barrier.
• For floating vinyl, and for laminate on plywood or concrete subfloors, per the product page.
• Works with electric and hot water heated floors, per Goodfellow.

Some vinyl underlays are made for one brand of flooring only, so always read the Use For or Use With line before you order.

Still deciding between the two floors? See laminate or vinyl planks: which one to choose.

Which underlay should I use in a basement?

If your basement floor is concrete, moisture is the big question. Concrete can let moisture vapour come up into the floor, and a waterproof plank is not always a moisture barrier. Check your plank's install guide to see what it asks for over concrete.

Before anything else, test the concrete for moisture. Our post on what a subfloor is explains how. If the floor is not flat, see what self-levelling underlayment is.

Then pick an underlay with a built-in vapour barrier. On the product page, look for Vapor Barrier: Yes, and for Grade Level: Below grade when the brand lists it. Below grade means below ground level, like many basements.

Richmond Quiet Block 3-in-1

• Rubber, a vapour barrier film and adhesive in one roll. Richmond calls it ideal for concrete.
• Above or below grade.
• Film side goes down, per the product page. The adhesive is there to seal the seams.

Roberts Black Jack 2-in-1

• Foam with a built-in vapour barrier (Vapor Barrier: Yes, Moisture Resistant: Yes).
• For floating laminate, bamboo and engineered wood.
• Plastic overlap and adhesive strip to close the seams.

Planchers 1867 SONO + EVA Black with vapour barrier film

• 3 mm EVA foam with a vapour barrier film (Vapor Barrier: Yes, Acoustic: Yes).
• For wood and laminate floors.
• Made in Canada.

AcoustiTECH VP

• 2.2 mm thick, with a built-in vapour barrier, for floating floors.
• Vapour barrier goes face up, per the AcoustiTECH install guide attached to the product page. That is the opposite of Quiet Block, so always follow the guide for your roll.
• Seams taped with vapour barrier tape, per the same guide.

What if your planks already have a pad and you are on concrete? A pad does not always replace a moisture barrier, so check your plank's install guide to see if it asks for one over a concrete subfloor. If you are not sure what your planks allow, contact us before you order.

For more basement ideas, see the best flooring for a basement.

Will underlay make my floor quieter?

It can. Underlays labelled Acoustic list two sound ratings. For both, a higher number means better sound control.

• IIC is impact noise, like footsteps or kids playing, heard in the room below.
• STC is airborne noise, like voices or the TV, heard in the room below.

So the IIC number matters most when someone lives under the floor, like on an upper floor or in a condo. Biyork says its Eco Quiet underlay (IIC 72, STC 73) is ideal for condos and multi-unit buildings. Black Jack lists IIC 70 and STC 66; Red UHD lists IIC 73 and STC 72.

What that means for you

• Check "Underpad Attached" first. If it says Yes, read the plank's install guide before you add anything under it.
• No pad on laminate? Get an underlay made for laminate, like Biyork Eco Quiet or Black Jack.
• No pad on vinyl? Get an underlay that says Use For: Vinyl, like AcoustiTECH LV or Red UHD.
• Basement on concrete? Test for moisture, then pick an underlay with a vapour barrier, like Quiet Block. Follow the guide for which side faces up and how to seal the seams.
• Someone living below? Compare the IIC numbers.

Not sure which underlay goes with your floor? Contact us and tell us which planks you picked.

Frequently asked questions

Can I put underlay under vinyl planks that already have a pad attached?

Only if both the plank and the underlay allow it. Torlys says its RigidWood Firm planks need no additional underlayment. AcoustiTECH says its LV underlay can go under floating click vinyl planks whose own pad is 1.5 mm or less, if the planks meet its minimum thickness. When in doubt, contact us.

Do I need a separate plastic vapour barrier if my underlay already has one?

Follow the guide for your underlay. Some say no: the Toucan EVA Foam & Foil underlay has a built-in moisture film, and Toucan says there is no need for additional films.

Which side of the underlay faces up?

It depends on the brand. Richmond says to put the Quiet Block film side down. AcoustiTECH says the VP vapour barrier goes face up. Read the label or the guide on the product page.

Can I use underlay over a heated floor?

Yes, if the product page says so. Look for Radiant Heat Compatible. Quiet Block and Red UHD list it, and Roberts says Black Jack is ideal over radiant heated floors.

Do I need to tape the underlay seams?

Yes, seal them the way the brand says. Black Jack has a plastic overlap and an adhesive strip, Biyork Eco Quiet has a built-in lip tape, and AcoustiTECH VP seams get vapour barrier tape.

Is waterproof vinyl plank enough on its own in a basement?

Not necessarily. A waterproof plank is not always a moisture barrier. Test the concrete first, then check your plank's install guide to see if it asks for a moisture barrier over concrete.