# Adhesive for Marble Threshold



## cabinetman (Jun 3, 2007)

> OK, here's my question: *what can I use to adhere the 2" x 36" marble strip to the cement subfloor?*


I've used thinset with no problems. Embed evenly.


----------



## Twister (Jul 5, 2009)

cabinetman - 

How thick should the layer of thinset be?

Also, is there any particular brand you recommend?

Thx!


----------



## Bud Cline (Mar 12, 2006)

Silicone is the worst idea for the reasons you mentioned.

Liquid Nails would work if you spread 100% of the marble and 100% of the concrete floor area the marble will consume. Then, stay off of that marble for about two weeks. The objective is to have no voids anywhere under the marble.

Thiset (modified) would work the best but mostly comes in 50# bags. What would you do with the remaining 48 pounds?

Thinset is available in smaller boxes if you can find it. If you do use thinset also use a small "v"-notched plastic trowel and coat both surfaces thoroughly. That will determine your thickness.


----------



## Twister (Jul 5, 2009)

Bud - 

What do you mean when you say "modified" thinset?

Is there any particular brand you recommend? The only big box store here in town sells a product called "Henry MarbleFlex 316". Ever used it?


----------



## Bud Cline (Mar 12, 2006)

> What do you mean when you say "modified" thinset?
> 
> Is there any particular brand you recommend? The only big box store here in town sells a product called "Henry MarbleFlex 316". Ever used it?


Henry's is one of the kings of quality adhesives - use that.

"Modified" simply means that the powder in the bag already contains all the additives you could ever need to create a high strength mortar adhesive.


----------



## rusty baker (Feb 13, 2009)

Wonder if you could glue that down with Kool Glide glue sticks? I have glued tack strip to concrete with them and powerstretched off it.


----------



## Bud Cline (Mar 12, 2006)

You need to have the bonding-area covering 100% of the marble surface. Any voids anywhere could result in cracks later. Holding power of the adhesive isn't as important as covering the entire surface with adhesive, not only for bonding but also for support. Any viscous adhesive would hold the marble in place even with only a few dots of adhesive but that isn't the point. Bonding strength is second to support in this case.


----------



## rusty baker (Feb 13, 2009)

You are the tile expert. I was just kinda throwing that out there.


----------



## Twister (Jul 5, 2009)

Guys - 

OK, thx for your recommendations. I'll use the Henry MarbleFlex thinset today and will let you know how it turns out.

Thx!


----------



## Twister (Jul 5, 2009)

*The Finished Product....nice, eh?*

All - 

Have been meaning to post these pix for almost 2 years. Well here they are. It turned out SUPER and so far there has been absolutely ZERO cracking of the underlying marble strip. I remember when I started asking around about how do floor guys install a threshold on top of a wood floor in such a way that the ends of the wood floor would not be exposed to the weather on the outside of the exterior door that I got a lot of blank stares at first. Well, if you have the same issue, here's one way to do it. Thanks so much to cabinetman and Bud Cline who gave me the good advice about thinset type mortar. Make sure you have ZERO voids/open pockets under the marble strip and your marble strip will be as solid as a rock (no pun intended!). :wink:


----------



## Bud Cline (Mar 12, 2006)

Wow! That was quick!:laughing:
Glad it worked out for you.


----------

