Tiling over insulation sheets

[countryboy]

Hi all,
This is my first time on here & boy do I have a doozy of a problem.
I've purchased electric under floor heating & the insulation sheets (not tilebacker boards, cost being the reason). The first thing that happened is that the adhesive supplied to me did not bond the sheets to the subfloor.
The floor is unsealed and the adhesive was for porous floors. Any ideas what I can use instead ?
Also I would love to hear some positive feedback about tiling on these insulation sheets. At the end of the day, they are just compressed foam, so there is still some movement (compression) in them. Has anybody used these successfully ? Thanks to all in advance.

 

[Perry]

Yes if its the dense foam used to use X7 on them years ago no probs with themete

 

[Daz]

I usually stick them down with Ardex X7R or Mapei Keraquick, lay the UFH, SLC with Arditex NA or Mapei Fibreplan, then tile with X7R or Keraquick (subject to the type of tiles being fixed) .

 

[countryboy]

Thanks pjc & Captain slow. I'm just relieved to hear that someone has tiled this way. I am definately going to use flex SLC. Thanks again.

 

[theyomper]

Just a tip......after you have laid the insulation board down.....lay some card or ply over the top. This will prevent you leaving footprints all over it and scuffing it up.

 

[countryboy]

Hi lads,
I poured the Arditex latex SLC 2 days ago. Everything looked good until I got home today. Cracks have appeared in the SLC. I'm worried that it hasn't bonded with the insulation. Do you think it would be still okay to tile over this ? Or do I tear it up ?:mad2::mad2::mad2:

 

[Daz]

First off, tearing it up will probably render your UFH etc, un-useable (bad times). As you opted for insulation boards based upon cost, we need a bit more info please.....

Can you post any pics of the cracks?
How thick did you lay the SLC?
Can you provide more info regards the mixing and setting of the slc, please?
How did you fix the UFH (loads of tape or spray glue etc.)?

 

[doug boardley]

First off, tearing it up will probably render your UFH etc, un-useable (bad times). As you opted for insulation boards based upon cost, we need a bit more info please.....

Can you post any pics of the cracks?
How thick did you lay the SLC?
Can you provide more info regards the mixing and setting of the slc, please?
How did you fix the UFH (loads of tape or spray glue etc.)?

that sounds like a damned good idea Daryl, have you tried it, and does it work ok?

 

[Daz]

that sounds like a damned good idea Daryl, have you tried it, and does it work ok?

Got the tip from Aaron, after he slated me for using silver tape. Yeah it works brill, on plywood, insulation boards and sand cement.....give it a go .

 

[doug boardley]

will do mate, I use spray glue for all sorts of little jobs, never thought of sticking ufh down with it tho'

 

[countryboy]

:mad2:Sorry I couldn't reply any sooner.
The SLC is 4-5mm thick.
I fixed the cable using tape. After the SLC was poured there are some parts of the wire sitting up close to the surface.
Rgds the mixing and setting : The Arditex RS plus powder was mixed with the RS plus latex and poured directly on to the UFH and isulation foam.
On closer inspection this morning the SLC is definately lifting in places.
What is confusing me more than anything is that the hallway is fine, with only some very minor hairline cracks.
Could the cracks be down to heat (quicker drying time) ?
Is there anything I can do to stabalise the SLC before laying the tiles ?

 

[jay]

hi could be a couple of probs to much tape (slc cant bond ) spray on ah is good in moderation hot melt glue gun is better. has the slc dried all the same colour also if its loose it has to come up be carful of ufh not to damage :8:

 

[diamondtiling]

will do mate, I use spray glue for all sorts of little jobs, never thought of sticking ufh down with it tho'

Hi Doug, get yourself a glue gun, sticks far quicker than spray glue, I use it for battons if the tiles are heavy and for ufh, I use spray glue for mosaics and get them smack on level and straight

 

[jay]

hi dont like the look of the second pic is it yellowish in color also whats your substrait looks like it hasnt bonded :8:i would recomend lifting the lot sorry

 

[countryboy]

:mad2:The SLC has discolouration in some areas.
The substrate is a compressed foam (insulation sheet) from Warmsoles.
Will it be possible to up the SLC without damaging the UFH ? (I bloody hope so).