marmox boards on chipboard floor - fixing

[bluesky]

evening all ,
been asked to fit marmox boards onto chipboard floor before fitting warmup heating .
what is best way to fix boards to chipboard? ( dont like chipboard !!!)
normally i use no more ply or take up chipboard and replace with flooring grade ply screwed to joists.
what adhesive to use and screws as well ?
all replies appreciated!

 

[Diggy]

I recently stuck them with SPF grey , then screwed them down using the marmox washers at 300mm centres.
Seems solid as a rock , then ufh and levelflex.

Diggy

 

[bluesky]

thats what i was thinking - just wasnt sure with spf onto chipboard .

 

[Diggy]

Forgot , prime the chipboard first with an acrylic , APD or similar.

 

[DHTiling]

As Diggy.... you deffo need washers be them plastic or metal..

 

[bluesky]

6mm marmox okay ?or not? height issue with anything bigger with ufh slc and tile

 

[DHTiling]

4mm extra... it's gotta be 10mm minimum IMHO..

 

[bluesky]

thanks dave , normally use 6mm no more ply but that is a lot denser so if you say 10mm then 10mm it is (unless someone says different !)

 

[ythan]

marmox boards provide insulation so makes the ufh more efficient and saves on electric bill, so 10mm will save more than 6mm.
marmox doesn't really add any structural strength to the floor, so no real difference there between 6mm and 10mm.

don't need to use adhesive to stick the marmox down if the existing chipboard floor is flat - just screws and washers as per marmox guidance.

 

[Qwerty]

marmox boards provide insulation so makes the ufh more efficient and saves on electric bill, so 10mm will save more than 6mm.
marmox doesn't really add any structural strength to the floor, so no real difference there between 6mm and 10mm.

don't need to use adhesive to stick the marmox down if the existing chipboard floor is flat - just screws and washers as per marmox guidance.

No!!! DO use adhesive, just as Marmox instruct you to do, otherwise the installation could easily fail.

Just finished a floor tiling job last week where a previous tilers installation of insulation board, UFH and porcelain tiles all failed due to it not being fixed with adhesive!

 

[ythan]

No, sorry, surely: the photos from marmox guidance video show 3 different types of substrates : one is fixing to a block wall: one is to a concrete floor: and the last one is to a wooden floor.

For a good flat wooden floor it is far easier and sensible to use just screws + washers at the recommended spacings, and then you not need to spend all that time and cost spreading a bed of adhesive.

On the blockwork wall there are only 5 red nails/screws, washers + 5 adhesive dabs per marmox board. The dabs of adhesive are there to support the board to allow for the fixing of the red nails (or screws).

On the concrete floor there is only adhesive and...... no screws+washers, for obvious reasons.

 

[One Day]

The purpose of the adhesive under boards on a wooden floor is to fill any voids which are often there but invisible - i,e, dips and bulges in the boards.
If (and only if) the floor is mirror flat - you could just screw the boards using washers.
Can't quite remember which manufacturer says this is ok - may be Warmup?

For the cost of a bag of sticky though, it can't hurt. 4mm trowel too.
Just be mindful that introducing water to chipboard and then trapping it under waterproof boards could in theory upset the chipboard - leading to more problems!
Rapidset if I were you.

 

[tilerbarry]

Sand the chipboard, make sure chipboard is screwed to joists, primer g, stick boards with kera quick and mechanically fix with marmox screws and washers. encase the ufh wires with ultraplan renovation screed.

 

[Qwerty]

I'm out!