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What is tile underlayment and what's it used for?

“Always pick your yard based on your Summer lifetstyle.”


November 21, 2018 - Karl Yeh

So you want to protect your new tile? What type of underlayment should you use? In this episode, we discuss what is tile underlayment and what's it used for. We explore the different types and brands as well as how thick it should be to be effective. 

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Karl Yeh:

Hi everyone, Karl Yeh here, and welcome to another Homebuyer's School video, a channel where you get the latest strategies, tactics, and tips from home buying experts. And remember, if this is your first time on this channel, and you want to get the latest strategies from the experts, hit the subscription button below, hit the little notification bell so you don't [00:00:30] miss anything.

So today I'm joined by Deborah Armstrong, Senior Interior Designer with Brookfield Residential.

And the question we're going to answer today is:

What is tile underlayment membrane and what's it used for?

So Deborah, let's kinda begin at the very, I guess at the top, what is title underlayment?

Deborah  Armstrong:                

It's a substrate that's used under tile to give added support.

You want to protect the tile from cracking. So there's many different kinds that we can use, depending on the [00:01:00] situation and the size of the tile.

Karl Yeh:                      

Is it the same as like floor tile versus countertop tile? Would it be the same type of underlayment or completely different?

Deborah  Armstrong:            

Sometimes, plywood's used on countertops a lot.

You want to make sure it's exterior grade because with the exterior grade plywood, they have adhesives in them that are waterproof. Especially on a countertop, that we are going to get water, or a bathroom, the same thing.

You want to make sure that whatever membrane [00:01:30] you use is waterproof.

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Karl Yeh:                       Great. So what,

What are the types of tile underlayment are there?

Deborah  Armstrong:                

There's three particular ones that are most commonly used. One again, was plywood anywhere from a 3/4 inch, 5/8 inch depending again on the support that's needed.

Karl Yeh:                       Yep.

Deborah  Armstrong:              

Cement board or cement backer board-Is another one. It's very commonly used. Again, the thicknesses are anywhere from a 1/4 to a 1/2 inch. [00:02:00] And again, depending on the size of your tile and the weight of your tile, will depend. And then you have the waterproof membranes.

Karl Yeh:                       Yeah.

Deborah  Armstrong:              

Again, Ditra mat is used a lot in bathrooms or anywhere where there's oversized tile as well. And it's a polypropylene type.

Karl Yeh:                       Okay. And then

What are some of the common brands?

Deborah  Armstrong:              

There's WonderBoard, there's HardieBacker, different ones like that, that are out on the market nowadays.

Karl Yeh:                      

Okay. [00:02:30] When I was doing the research for this video, you know, the one that keep kept coming up is DITRA tile underlayment. What is that?

Deborah  Armstrong:                

You probably have seen it maybe in the home hardware stores, or your big stores.

Karl Yeh:                       Yeah.

Deborah  Armstrong:                

It's a bright orange grid type underlayment that's laid down under the tile. Again, usually we use it when you're using like a 12X24 or 24X24 inches tile.

It's got grid so that the [00:03:00] cement can goes down into it to add extra support for the tile and a little bit of a cushioning to prevent the cracking.

Karl Yeh:                      

Is it more used for like basements, were like you have a maybe a concrete floor?

Deborah  Armstrong:              

No, no. Concrete itself is a great substrate. You can tile directly on top of concrete.

Karl Yeh:                       Okay. Yeah.

Deborah  Armstrong:              

As long as the concrete's really, really clean and there's no cracks in it, you want to make sure it's also very, very level.

If it's not, you want to use a self leveling cement [00:03:30] down first, and then you can tile directly on top. If you're using larger tiles and you want to feel a little bit more comfortable Ditra mat, you can never go wrong with.

Karl Yeh:                      

Wouldn't you want to use Ditra mat maybe across your whole house or does that impact anything else?

Deborah  Armstrong:              No, it doesn't impact anything else.

 If you're using tile, it's a great product and you know, you're just going to have that added assurance that your tile that you've put down is not going to crack.

Karl Yeh:                      

How thick should these under tile underlayment be?

Because I know [00:04:00] you, you were saying like, when you put down certain tile they should be certain thickness and then maybe for different types maybe for different maybe rooms in your house, you'd have a different thing. So how would you know?

Deborah  Armstrong:              

Well not necessarily. It depends on the product that you want to use.

So if you want to use cement board, which is one of the better underlayments- ... it only comes in 1/4 inch or 1/2 inch.

Sometimes you want to take in consideration is it going to butt up against a hardwood floor, because you don't want to have the areas where they meet [00:04:30] at two different heights.

You don't want to have that transition strip- to be a real toe kicker.

So you want to take that into consideration plus the size and the weight of your tile. The whole idea of having that underlayment is to prevent it from cracking.

Karl Yeh:                       Okay.

Deborah  Armstrong:              

So you do want to make sure that you have the right support. If you're using DITRA mat, it's only an 1/8 of an inch. That's why it's very commonly used.

Deborah  Armstrong:              

You're not going to get that real high transition area, because of course you've got the thickness of your [00:05:00] tile as well.

Very important if you're using an LVP product. An LVP's very thin. So if you're going up to a 1/2 inch backer board with another 1/8 of an inch top, your transition's is going to be very large.

Karl Yeh:                      

And if you want to know more about luxury vinyl plank, watch our video above.

So, Deborah, do you have anything to add in terms of tile underlayment?

Deborah  Armstrong:              

No, other than make sure that you do use an underlayment in moist areas being a waterproofing membrane.

And then you also want to make sure [00:05:30] that if you're using oversize tile, that you have the support. Otherwise, those tiles will crack if you're just laying it on your sub floor.

Just the flex in that floor alone will cause cracking.

Karl Yeh:                      

Perfect. Well, the question I have for you today is,

What type of tile underlayment do you use? And what was your experience with it?

Let us know in the comment section below. Thank you very much for joining us, and we'll catch you next time.

Your turn:

Let us know if you have additional interior design questions that we can answer by submitting them in the comments section below. 

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