CHIPBOARD directly onto concrete?

[mikeey84]

Hi All, we are about to start the renovation of our kitchen, and at the moment its is rotten lino on top of what look like terracotta tiles onto cement.

What I would like to do is:
Remove tiles
Ensure floor is flat
Install DPM (either liquid or sheet)
Install Chipboard
Then lino or laminate.

My question is, can i screw the chipboard directly onto the flat concrete slab (with dpm) or do I have to use joists? Its just i dont want to remove too much of the floor. If i have to use joists could i cut trenches into the concrete to bed the joists in as I cant increase the height of the floor by more than 10mm.

thanks in advance.....

 

[xr4x4]

i wouldnt use chipboard, it soaks up water like bloting paper.

marnie ply is quite cheap, if you get the rough stuff.

not sure about the fixing question, if you create a DPM, last thing you want to do is drill holes in it.

 

[mikeey84]

The attachement is the key point, as i dont want to spend time and money putting a dpm down only to put great big holes in it when I attach the ply.

Maybe I could drill the holes in the floor and fill with silicone, that way when I put the fixings in it remains watertight?

Any suggestions would be greatly appriciated!

 

[JohnD]

you might consider using a paint-on DPM like Synthaprufe or Aquaprufe or whatever is on the market now. It is a sort of black rubber solution, rather than plastic sheet. If you drill into it you could fill the holes with silicone before pushing plasplugs into it for your screws. (I have not tried this myself)

 

[mikeey84]

I have seen such paint on dpms in wickes, and it mentions on the label that they should be covered by screed (i think 50mm). Would 12mm marine ply be a suitable replacement???

 

[JohnD]

sorry, I don't know. The screed is so you don't walk on it in your heavy boots and wear holes in it, but it is often used when building, on the oversite concrete as it is less easily damaged than polythene by the builders. Maybe phone the makers. I have seen it used on old solid floors and vinyl flooring laid on top. Possibly you could use a combined DPM underlay and put down a floating floor which needs no screws or nails. If you have room you can include foam insulation boards which will make the kitchen warmer.

 

[Richard C]

Have you considered using something like this;
http://www.insulationexpress.co.uk/Tile-Backer-Board/Marmox-Waterproof-Insulation-Boards.htm
This will give you a waterproof barrier, insulation & you (or someone else) can tile onto it in the future if needed.

If you decide on the membrane/ply route (not ideal IMO), you don’t need to go to the expense of Marine ply; WBP uses similar waterproof adhesive for the laminates, just doesn’t have expensive finish veneers of Marine ply.

 

[mikeey84]

marmox sounds like a plan, however is it suitable if I am not planning on tiling?

 

[Richard C]

It's a reinforced cement fibre insulation board primarily for use when tiling but I don’t see any problem, as long as you cover it up with something as it’s not a wearing surface. Ifin doubt check with the supplier.

 

[Deluks]

You still need a dpm under marmox. If you have solid concrete beneath you should use self levelling screed and a liquid dpm, not just the black stuff. See mattysupra's stickies at the top of this forum:

//www.diynot.com/forums/viewforum.php?f=16

Insulation is strongly recommended in any case.

A word of warning to the OP, did exactly the same last year, but when I pulled the quarry tiles up I found they were laid on an inch of sand/cement over bare earth. Which explained why the floor was always damp and cold.

Ended up digging out a foot, repairing rotten joists in the next room which were up against the soil. Hardcore, dpm, insulation and concrete, added about £450, lots of digging and disruption. So be prepared if you want to do this right.

Plus side, have added a circuit of PEX pipework for future underfloor heating, and have a dry, warm, leak resistant and long lasting floor.

Still haven't gotten round to tiling it

 

[Richard C]

did exactly the same last year, but when I pulled the quarry tiles up I found they were laid on an inch of sand/cement over bare earth. Which explained why the floor was always damp and cold.

 

[Deluks]

First tile to be lifted, up pops a massive ragworm

I think the floor was redone in the seventies, found some 1972 newspaper stuffed in some cracks, and rotten bits of timber in the soil, indicating that there may have been a rotten suspended timber floor that was ripped out and filled in with earth.

 

[big-all]

synthaproof or similar membranes are very fragile like a balloon/thin plastic and need to be fully covered with a permanent non moving surface as the they have no wear/rubbing resistance at all

 

[mac391]

All of this sounds expensive !! a simple 3mm screed on top of the tiles is all you need. Lay a laminate as opposed to vinyl and use DPM underlay... Easy !!