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Concrete slab; hydronic radiant heat; porcelain tile - Making the right sandwich

Concrete slab; hydronic radiant heat; porcelain tile - Making the right sandwich

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  #1  
Old 02-18-13, 01:17 PM
J
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Question Concrete slab; hydronic radiant heat; porcelain tile - Making the right sandwich

I am new here and I did take some time searching and looking at other threads before starting my own. Hopefully, the pictures have uploaded and will prove helpful.

We lost our den during Hurricane Sandy. The room behind the den was tiled with ceramic tile and it faired well. Just scrub the grout, disinfect and as good as new. Hurricane Sandy provided the stimulus to redo the den.

The den was, once upon a time, a two-car garage. With adjacent space it is about 500 square feet. The split-level home was built in 1955 and the concrete slab sits on sand, presumably without insulation or any kind of vapor barrier. Water intrusion is not a problem unless we have another tidal flood incident.

I have the old garage down to bare concrete with vestiges of mastic which once held oak parquet tiles in place. The current den includes what was once an adjacent room where the floor is lower by 3/4." Currently, this adjacent space has vinyl (possibly asbestos) tile with tar-like mastic remaining.

Here are my tentative plans and questions - the reason for this post:

1 - Can I use a concrete based leveling compound to "equalize" the two floors, going over the top of the old mastic and vinyl tile. Here my concern is toxicity if I were to start trying to remove the tar-like mastic and vinyl tile. I'd rather just bury it if I can.

2 - Once leveled, my current thinking is to use Roth panels to provide radiant heat. What I like about the Roth panels is that they are an all-in-one insulator and carrier for the Pex tubing and provide aluminum heat spreaders - all while only adding about 1" in height to the concrete floor. Any suggestions about this approach from the pros will be appreciated?

3 - My thought is to use 1/4" CBU over the Roth panels screwing in place with Tapcon screws through the Roth panels and into concrete, trying my best to miss the tubing! Does anyone see any issues with this approach?

4 - Do I need a vapor barrier or other layer of isolation anywhere beyond what is provided by the Roth panels?

I'd like to keep the total height of the "sandwich" to around 2" to 2 1/2" max.

At this point, I intend to bring in a pro to install the porcelain tiles. We intend to go with natural wood-look porcelain planks.

Comments welcome and encouraged.

Joe
 
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  #2  
Old 02-19-13, 09:27 AM
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1) you can definitely encapsulate the old tile and mastic with a leveling compound. I would refer to Ardex or a similar manufacturer to select the correct product. It is always better to eliminate asbestos when possible but understand your reasoning for leaving it.
2)Not really familar with Roth specificall but why not pour the leveler over the radiant panels and use the leveling compound as a heat sink? If you have an air compressor simply fill the pex with air under a little pressure to test for leaks. leave the air in the system while the leveler is poured. If you see bubbles you need to make a repair. I am not an expert on Hydronic heat so I may be wrong about this one.
3)As stated above I would avoid this step by flipping the Roth and the leveler.
4)I would add a VB over the slab before installing anything else. If you can protect it during the work it would not have to be overly tuff. It may not be required at all but i should be cheap insurance.

Unsolicted opinion: I have never been a fan of one material designed to look like another: tile that looks like wood, vinyl sheets that look like tile, wood that looks like marble, epoxy that looks like terrazzo, etc. Just my opinion but they never seem to actually look like what they are trying to look like. I realize that the tile you are talking about are popular now and they are not bad at all, just not my thing.
 
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Old 02-20-13, 10:41 AM
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OK,

I took up all the wood.

So it looks like the vinyl tiles and ugly tar-like cement will come off without a tremendous amount of effort as I was able to remove half a dozen of them easily.

But they are 9" x 9" gray pigmented vinyl tiles and likely to have asbestos content (probably not friable.)

Can I pour leveling compound over them anyway or must I take them up?

The under-floor is concrete, so no fear of any flexing or instability.

My concern is disturbing anything with asbestos content as little as possible.

Regards,

Joe
 
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Old 02-20-13, 10:54 AM
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Spiper,

Thank you; I missed your post before placing my second post.

I will look into Ardex. I have removed friable asbestos from pipe-covering used in the steam heating system of another house I own built circa 1925, employing various protection schemes, and there I could not encapsulate the asbestos.

Here, it would be buried under at least 3/4" of concrete or concrete-like material.

What I like about Roth panels is this:

The VB and insulation is part of the system.
The profile is low - about 1"
The Pex tubing snaps right into place.
Aluminum heat spreaders cover almost all of the square footage, so there should be maximum heat transfer to the thinset and porcelain tile above.

It's a "system" rather than a collection of individual and customized layers.

I tend to research things pretty thoroughly and listen to advice provided by the more experienced before I spring into action. So I am open-minded to alternate approaches.

I have already examined this wood-like porcelain tile and it looks amazingly like wood even in high traffic areas.

You have to see it to appreciate it.

Unlike wood, though, it will do a fine job transferring heat from a radiant system below.

Compared with metal or stone, wood is an insulator.

Regards,

Joe
 
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Old 02-21-13, 06:03 PM
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I think your choice of tile will be fine, the digital imaging now used has taken the looks of tile to a whole new level. Depending on the length, I would use a 1/3 or 1/4 offset for each row to minimize issues with tile warpage and the resultant lippage.

As far as putting CBU down, how about a membrane instead. Something like Ditra goes down with thinset so no need to use screws. A membrane also would help with thermal expansion issues where the heating tubes warm up bodies of different materials in the tile sandwich at different rates. Excessive expansion could cause a tile to debond or crack
 
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Old 02-21-13, 06:19 PM
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As far as removal of the vinyl asbestos tile, if they are coming up easily, then I wouldnt want them as the base for any concrete pour. If they continue to come loose over time and with the introduction of heat, maybe sooner than later, they are like a slip sheet under the pour. A new concrete layer, if isolated from the old should be at least 1.25" thick. Without enough thickness and weight, you have the makings of a giant peanut brittle candy bar under your feet. You want the new layer to bond to the old concrete, the vinyl might be running interference. The black goo is commonly called cutback, dont know the origins of the term, but it can stay. In the past I have flat troweled a screed coat of modified thinset, one that says on the bag that it can be used over cutback, over the goo then made my self leveling cement pour. I think SLC would be too expensive for the area you are considering but take the other fellows advice and contact a tech rep from Ardex or whoever.
 
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Old 02-22-13, 11:39 AM
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Thanks, Bob,

As I do some additional research, I'll be mulling over whether or not I want to take up the VAT floor. I'd really rather not disturb the asbestos (and have to dispose of it properly,) but I don't want to worry about peanut brittle underlayment either.

To put the project into better size perspective, the total square footage of the den is approximately 410 sq feet. The portion that was originally garage is 281 square feet. The garage portion is pretty level and will need very little prep before laying down the Roth panels or other VB, insulation and support framework for Pex piping.

The portion of the floor that needs a 3/4" height increase to level with the garage is 127 square feet. I suppose, as a novice at floor leveling, this is a small enough leveling project to be done by two people, one to pour and level and one to mix the next batch. It seems placing a bunch of screws at the right height ahead of time will assist in using a squeegee or other spreader to get a level result.

I have been reading threads about Custom LevelQuick RS and Ardex and it seems that folks familiar with both products tend to prefer Ardex. Looks like I can get a mixing barrel and some other mission-related tools at Bontool.

I am not too worried about the expense per square foot. It isn't a very big project - and I am more concerned with achieving the result I desire - a maintenance free floor sans organic component products that will clean up well after a flood.

~Joe
 
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Old 02-22-13, 06:01 PM
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Yes, definitely a two person job on the pour. Somebody, maybe Ardex used to have a rake with teeth that had adjustable depth stops. Ardex is a good companywith knowledgable field reps. Call their HQ and get to the person in your area. He/she will have additional info, tips, insight, etc, plus the ability to put a set of eyes on your project and steer you right
 
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