Questions tagged [underlayment]

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Working with Concrete like float between plywood and flooring

I am total beginner, so please bear with me. I live in a second floor condo unit (built around 1997). I recently removed a closet and discovered that my carpet rests on some sort of underlayment, ...
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Can you wet shim above a tub?

Is it possible to wet shim around a newly installed tub to bring all the walls plum and flat before tiling? Using a foam waterproof backer board and want to make sure that I’m laying tile the correct ...
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Should I add a plywood underlayment between my chipboard subfloor and new wood floorboards I want to install?

Question I’d like to remove carpet in a bedroom, and install a 14mm thick engineered oak floor instead. (The floor boards will have a multi-ply core, like these ones). Between the chipboard subfloor ...
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2 answers
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What is this type of subfloor (mesh and stone?) and what's the easiest way to remove it?

I removed some tiles today and found not just thinset and an underlayment but a few layers of mesh and what appear to be stones or concrete. What is this, why was this used and is there anything ...
2 votes
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Karndean over underlay

I'm laying Karndean Korlok planks. I've taken out the engineered wood floor I'm replacing. I have a Tredaire underlay below over the concrete, that for acoustic insulation. It's 6mm thick rubber. Do I ...
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How to flatten surface for LVP?

Updates on a project that I posted about previously. In my living room, I have removed the particleboard that was beneath the carpet. I put a long level to the plywood (5/8") beneath, and found ...
2 votes
1 answer
72 views

What type of subfloor material is this?

I ripped out the carpets and foam underlayment from the living room of my 1975 oceanside New England townhouse. I’m trying to figure out if this is homasote/ hardboard/fiber board or plywood. I don’t ...
1 vote
1 answer
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Click-lock floating engineered hardwood over particleboard?

Bought a house Friday. House was built in 1975. Carpet with particleboard beneath looks to be relatively new. I pulled up the carpet and the particle board is in great shape. No stains or water ...
1 vote
2 answers
597 views

How to fasten 1/2" plywood underlayment to 1/2" plywood subfloor

I'm preparing my floor to install new 3/4" solid hardwood flooring. I started off ripping up the old carpet and 5/8" particleboard. That left the 1/2" plywood subfloor. My plan is to ...
-1 votes
1 answer
428 views

Can I use an underlay on glue down vinyl planks?

I would like to reuse some luxury vinyl planks (5 year old Armstrong Luxe Plank with FasTak pressure-based adhesive, just under 4mm thick) that I pulled up from my concrete basement floor and put them ...
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1 answer
148 views

USG Fiberock underlayment used for tile installation

I reinstalled the tiles in the laundry room and the installer used USG Fiberock, instead of Hardiebacker - as initially told me. He’s telling me that USG Fiberock is good for laundry room. But now I ...
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How large of a hole can I cover with just 1/4" underlayment?

I am redoing a bathroom and as such I am moving the shower feed piping (~3/4" holes), the drain (~2" hole), and also an air return (4x8" hole). I plan to use porcelain 12x24" tiles....
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1 answer
798 views

Installing 3/4" plywood underlayment over 1/2" subfloor

I've seen many variations of my situation discussed here, but I'm new to all of this and I want to make sure my plan is sound. I'm finishing a bonus room over the garage that currently has only a 1/2&...
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69 views

12x24" Porcelain Tile over 2x6x1.5" T&G Spanning 48" Beams

I have some questions in regards to installing 12x24" porcelain tile over 1/2" plywood underlayment that sits above 2x6x1.5" T&G subfloor that is supported by posts and beams on 48&...
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1 answer
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Does combining a hybrid vinyl plank with attached underlay and external underlay help to achieve even greater soundproofing?

Hybrid vinyl planks come with acoustic underlay attached to them. For example the one that I am after has LnTw of 40 db. The question is if I install that on top of an extra 2mm acoustic underlay, say,...
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Stone tile flooring with acoustic sound reduction requirement in condo

We just closed on a new condo and want to replace some of the old carpet with stone tiles. However, the HOA has a sound reduction requirement where the floors must pass acoustic testing with 55 IIC or ...
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For a floating floor - Is it safe to use an underlayment above an existing vapor barrier?

I have a concrete slab floor, and it was very uneven, so I placed a vapor barrier down (6ml poly) and then I nailed 3/4" plywood overtop. This fixed a lot of issues with the floor being uneven. ...
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1 answer
302 views

Does DMX 1-Step underlayment need to be screwed down onto concrete?

I am looking to use DMX 1-Step dimpled underlayment in my basement for a finishing project. I looked at the installation checklist and it does not seem to mention anything about how it attaches to ...
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How should we complete this laminate installation?

Problem I purchased some pergo gold underlayment and pergo waterproof laminate flooring and installed it in the kitchen with my brother. This was our first time ever installing any type of flooring, ...
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1 answer
111 views

Can I use a flooring underlayment in conjunction with a LVP plank that already has an underlayment built-in?

I'm replacing an old LVP floor, which required an underlayment, with a new brand LVP that has an underlayment built-in. I'd think that to mitigate sound and vapor, a reasonable thing to do is to ...
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Several layers of polyethyleen sheets as a vapor barrier under underlayment & laminate

I am putting 7mm laminate on concrete. I have underlayment (5mm) that requires >0.2mm polyethyleen (PE) sheet as a vapor barrier. Unfortunately, I couldn't get >0.2mm PE but got 0.16mm PE ...
1 vote
1 answer
70 views

A creative Eco-friendly Underlayment for a metal roof? [closed]

I am building an octagonal cabin with a 200 sq ft metal roof (Grandrib 3) at a 30 degree pitch; the roof will sit on wooden strapping and will eventually have insulation below it contained by a ...
1 vote
1 answer
903 views

Need to level OSB board for LVP, pros and cons of using roofing shingles?

I am looking into inexpensive options to level OSB for installing luxury vinyl planks. I read an article that talks about using roofing shingles to level out subfloors before installing hardwood. I am ...
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1 vote
1 answer
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How to install pre finished hardwood over existing softwood floor

I have 200 square feet wood floors that do not appear to be hardwood, they are in pretty bad shape and need refinishing or replacing. The quotes we got for refinishing are $600. As I said the floor ...
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269 views

Laminate floor directly over plywood subfloor ok?

We just ripped up carpet in a room and found that it had 1/2" plywood over the joists and 5/8" particle board on top of that. We are planning to install 10mm laminate flooring in this room. ...
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1 vote
1 answer
463 views

Plane floor joists, sand subfloor, or sand underlayment to handle hump in floor for cork plank flooring?

I am planning to install 5/8 in. plywood underlayment for some floating 1/4 in. cork plank flooring. Unfortunately, there is a hump in the floor spanning three joists, based on my measurement and ...
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1 vote
2 answers
173 views

How should I handle reflooring the bathroom of an old house?

We are updating the bathroom in our old house and after removing the old tile and concrete we found that it was sitting on 3/4" subfloor planks, and some of them are not in the best shape. We are ...
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1 answer
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What tape is appropriate for underlayment?

I am installing bamboo flooring with Floormuffler underlayment. This type includes a moisture lip & adhesive for joining the long sides. I have a few seams to join that don’t have the lip/adhesive,...
2 votes
1 answer
786 views

Subfloor repair for LVP installation

I'm preparing to install luxury vinyl plank in the living area of the second floor condo I just bought (carpet was installed previously). It's a woodframe condo with a wooden subfloor built in 1985, ...
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1 vote
1 answer
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Should I have my contractor redo the underlayment?

I’m having my roof redone and on the roof where my roofer is going to install standing seam metal roof he put down Winterguard HT fastened with staples (because it was cold so it didn’t stick well). ...
1 vote
1 answer
626 views

Best method to use carpet samples squares to create a Rug? [closed]

I have plenty of carpet samples and I wanted to make an area rug with them. I would like to make a rug out of them, maybe I can create a pattern with the carpet squares and then glue them to some ...
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1 vote
1 answer
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Why is it a bad idea to install self-stick tiles over luan plywood?

I am intending to instal self stick tiles over a primed luan underlayment in a bathroom. However, the manufacturer's instructions clearly state: DO NOT install over unsuitable or unstable subflooring ...
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1 answer
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Underlay for saddle roof? Does side matter?

I am renovating my attic. Because the house is about 150y old there is no underlay. I installed an underlay from the inside by stapling an underlay to the bars which hold the roof. The underlay should ...
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What underlayment material is this? Is it safe?

This underlayerment was found in a bathroom. It was under a cement layer with tiles on top. The house was constructed in the late 1980s. What material is this underlayerment made of? Is it safe to ...
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1 vote
3 answers
2k views

Suggestions to hold floating laminate floor from sliding on vapor barrier installed over concrete slab

I need suggestions for keeping a laminate floating floor in place during installation on a vapor barrier over concrete. I was hoping to hear of good ideas to prevent this slip/slide effect on the ...
1 vote
1 answer
868 views

What kind of underlayment material is this?

This was found under two layers of sheet vinyl flooring in a late 1940s house. Subfloor is fir and there appears to be a black tar-like mastic between it and the wood. The green underlayment feels ...
1 vote
1 answer
1k views

Do I need to add plywood underlayment over plywood subfloor?

I am replacing downstairs flooring that had three layers before the subfloor. Linoleum, Cement Board and Tile. All flooring had to be removed down to the subfloor due to water leak. Since the cement ...
0 votes
1 answer
218 views

Why is roof underlayment nailed in?

Roofing underlayment ("felt") is immediately covered with shingles which are nailed in. So what isn't it redundant to nail in the felt as well? If the only purpose is to keep it from sliding off ...
3 votes
1 answer
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Do I need to remove cap nails before re-roofing?

If I have existing decking with old tar paper that I want to remove the tar paper and install synthetic underlayment, do I need to remove all existing cap nails in addition to the tar paper or can I ...
5 votes
5 answers
6k views

Can I install heat mat and backer board over cork flooring?

I am installing a new bathroom floor. I plan on getting an electric underfloor heating mat, 2 backer boards for under the heating, screed the mat and tile over this. My question is can I place the ...
0 votes
1 answer
565 views

What sort of nails should I be using on Sheet Vinyl underlayment?

I'm adding some Vinyl down in a shower room and nailed down the underlayment. But the nails keep popping up a little evey time I add more nails. I'm concerned these will be felt under the vinyl. ...
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2 answers
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What type of underlayment is appropriate for metal roofing?

I'm building a shed with a metal roof. What underlayment material should go between my OSB roof deck and the steel panels?
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1 answer
1k views

Tile underlayment, Ditra vs wire mesh lath

My previous kitchen tiles were laid on top on wire mesh and mortar. Except for a few smaller grout cracks they were relatively okay and flat. After removing the tiles, mortar, and mesh I have ...
1 vote
0 answers
255 views

Installing Plywood Underlayment over Plywood Subfloor

We are renovating an apartment and trying to install a 3/4'' solid hardwood floor in the living room. We pulled out the existing carpet along with a 5/8''particle board underlayment. Under that we ...
0 votes
1 answer
242 views

Subfloor tolerance for engineered hardwood

I am installing (floating) 3/8" engineered hardwood with 1/8" QuietWalk underlayment on a cement slab. I have used a grinder and leveling compound to remove the large valleys and hills. Now I have ...
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Can I use underlayment to increase thickness level of engineered flooring

I need to increase the 1/2” thickness of the engineered flooring as much I can. Is it ok to use 1/8” underlayment. I plan to nail not float.
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Underlayment (vapor, moisture and sound abatement) under marble tile floors

Do you use an underlayment (vapor, moisture and sound abatement) on top of concrete subfloors and under marble tile flooring? Ultimately the marble will not be installed using traditional mudding ...
0 votes
1 answer
121 views

How messy to get underlayment off of concrete floor?

Because of my cats, the carpet of my dining room is really in horrible shape. I live in a townhome. I replaced carpet on the second floor with bamboo flooring without too much mess since the ...
1 vote
2 answers
1k views

Tile over 2x6x1.5 T&G subfloor, spanning 48" beams

Long time lurker, first time poster. I think I might have a solution to my problem but I'd like to get some peer review on it before I start work. I'm remodeling a master bath (50sf, 10x5) in a 1966 ...
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Flatness requirements for bamboo laminate flooring

I'm installing Lumber Liquidators' Morningstar XD bamboo laminate flooring in my basement. According to their tech support, they have the following flatness requirements for the underlayment: (1) ...