RPM Mat on concrete-GLUE?

[Freezeman]

I understand the only method recommended to apply RPM mats onto concrete is to use Bostik Hydroment Ultra Set Advanced. I am about to have some shipped from WA. to Co. in order to get some to do the job, yet I am sort of shocked that all the distributors listed on Bostik's site of the product in the Denver Colorado area claim to not stock it or are unable to order it in. WTF
Has anyone used with, good results, some other brand of this type of adhesive?
I have some old mat material left over from another job and I am going to do a test run just using Ready Guard to see what happens with it, yet I doubt it would be as good as Ulta set would be. It's just a shame it's about $2.00 a sq. ft. just for the glue to stick the $2.40 per sq. ft. mat down.

Per sq. ft.
$2.00 glue
$2.40 Mat
$1.50 SLC
$1.00 thinset
$6.00 Tile
$8.00 wire
= $30.00 per ft. before I get to try and make something for doing a good job with all the crap.

[Tiger Mountain Tile Inc]

I'm surprised that you can't get any ordered in either. Ultraset is a trowelable urethane. I don't know of any competing products. It works. If you can't do it with Ultraset, it can't be done.

[The Kid]

Why use the rpm mat at all then, my thinking is you already have to slc it why not omit that product and save yourself a bunch of money.

[Tiger Mountain Tile Inc]

I know what you are saying but, on concrete, he would have to treat the cracks and do some sort of insulation (cork, etc) both of which are accomplished with RPM mats and ultraset. Not to mention having to hot glue all the wires down would take a lot of time.

[cx]

Jim, I don't believe the RPM Mat claims any sort of insulation value and you'd still need to add an insulation layer if you want one.

[Tiger Mountain Tile Inc]

Good catch. I thought that they did advertise that but apparently it's just a "thermal break"

From the RPM site:

RPM mats, together with the adhesive used to adhere RPM to concrete, provides a thermal break from the substrate and allow more of the heat wire’s energy to be directed toward the surface. This means less heat loss down into the concrete and more energy efficient heat radiating to the floor surface. Keep in mind RPM mats are not an “insulation” product and we recommend using RPM mats in conjunction with a ¼” thick cork underlayment for assured insulation.

[Freezeman]

RPM displaces 50% of the SLC, that equals 75% of the cost of the mat.
I like that part. The ease of running the wires, the protection of the wires, and the ease of pouring the SLC.

To be honest here, I am planning on skipping the insulation.
As I understand cork shouldn't be used instead the synthetic cork should be used and I would have to apply it with ultra set which would double the amount that I would need.
IDK yet I would think a nice layer of ultra set and a layer of thick plastic has to do quite a bit of good towards directing cold or heat towards the directions that are needed to warm the floor. Maybe I should Google to see what a Thermal Break really is.
Beside that the contractor just wanted me to lay the wire and tile over them, simple right.LOL
I wish Detra would get their mat for wires available someday.

[Jhereg]

Straight off his site.

Use as an Anti-Fracture Membrane Over Concrete Slab

Over concrete, RPM mats are a TCNA tested and approved “High Performance” (highest rating) method of anti-fracture membrane in accordance with ANSI A118.12 system crack resistance/isolation test. The “High Performance” rating means that after an 1/8” crack was created in the slab, there was no failure or cracked tile.

Use as a Thermal Break Over Concrete Slab

RPM mats, together with the adhesive used to adhere RPM to concrete, provides a thermal break from the substrate and allow more of the heat wire’s energy to be directed toward the surface. This means less heat loss down into the concrete and more energy efficient heat radiating to the floor surface. Keep in mind RPM mats are not an “insulation” product and we recommend using RPM mats in conjunction with a ¼” thick cork underlayment for assured insulation.


I also prefer easy-mat to cork, only needs modified thinset to go over slab, or go prime/peel & stick.

[Charimon]

What they need to do is bond spunfiber mat (Ditra, Stratamat) to the bottom of the rpm.

[madronatile]

If you're only filling up the voids and don't need to level you can save cash and fill with less expensive stuff. We used to use 3:1 mixed with admix. As long as you prime properly you should be good to go.