Chipboard flooring under tiles

[Master of None]

I am halfway through refurbishing my kitchen and bathroom and have just finished laying the floor with 22mm green MR TG caberboard chipboard (as advised by a builder colleague of mine). Now after reading this forum i have seen many threads saying no no no.
1. Is there a product i can paint onto the chipboard to seal it and so protect it against water ingress which tiles will still adhere (i was going to tile straight to it due to a height restriction, i have glued the joints and fitted nogins to all edges of all boards to prevent movement).
2. If i have to overlay it with some thing, what? max 6mm.
3. Should i tile under Kitchen units and bath to protect it? it will double the cost of my tiles.

 

[mattysupra]

you need to re-post this in the tiling forum. The guys and girls over there will have your answer. The mods will tell you off for making double posts tho.

 

[gcol]

Ok welcome to the tiling forum!
Right, as we don't ever tile onto chipboard of any type, (unless you're a gambler - see below) you need to overboard. Normally this would be 12mm WBP ply or in your case, 9mm ply sounds like it would be fine. However, if you are sure that you cannot go any thicker than 6mm then instead of screwing down the ply you'll need to glue it down over the face of the sheet. Use something like this http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=A336110&ts=66643&id=72054

Right, if you feel like gambling, get yourself some Bal fastflex and you may be able to lay directly onto the chipboard. Now I strongly recommend not doing this and you should overboard as mentioned. Fastflex is very expensive and to me, you're better spending the money in preparing the floor properly.
Let us know how you get on and good luck.

 

[JohnD]

or you might consider ripping the chipboard up and re-doing it with WBP

 

[gcol]

That would be the ideal scenario John, but as he's glued it all down...

 

[wap]

you could use a product called no more ply. its only 6mm thick and equivalent to 12mm ply

 

[Master of None]

sorry i have not responded i have been away. Thank you all for your help.
But please just a little more.
I have realised that if I don’t put the plywood or tiles under the cabinet legs in the kitchen, height build up is not really a problem. However i would still like to protect the chipboard in the event of a spillage. Any ideas?
also the no more ply product sounds good, but is it water resistant or water proof i.e. will water penetrate to the chipboard?
No more ply equivalent to 12mm ply? in stiffness? will it add any stiffness to my floor (22mm chip on 600crs joists) however i have added noggins at every edge so effectively 600 squares. In essence 9 or 12mm WBP or 6mm no more ply?

I now hate chipboard........

PS. i have another thread regarding my walls which know one seems to answer. i can only presume every one thinks i am to lazy to search previouse threads. i have read the wiki and hundreds of other threads and the solution seams to be tanking (what is this?) thanks in advance.

 

[gcol]

sorry i have not responded i have been away. Thank you all for your help.
But please just a little more.
I have realised that if I don’t put the plywood or tiles under the cabinet legs in the kitchen, height build up is not really a problem. However i would still like to protect the chipboard in the event of a spillage. Any ideas?
also the no more ply product sounds good, but is it water resistant or water proof i.e. will water penetrate to the chipboard?

http://www.nomoreply.com/index.htm
Quotes from their website:
Dimensionally stable, unaffected by moisture absorption.
Which means that it will not break down if it gets wet but it will absorb moisture and allow it to pass through to your chipboard.

The perfect substrate for all tiles in bathrooms & kitchens. Ideal for wet rooms. For total waterproofing use SBR Primer.
Dammit, you mean I've been wasting my time tanking when a coat of SBR would waterproof totally! Yeah right...

No more ply equivalent to 12mm ply? in stiffness? will it add any stiffness to my floor (22mm chip on 600crs joists) however i have added noggins at every edge so effectively 600 squares. In essence 9 or 12mm WBP or 6mm no more ply?.

Sure it'll stiffen things up. Would a 6mm board, glued down and held in place with a few screws be as rigid as 12mm ply screwed every 200mm? I'm not so sure. For your floor with 600 ctrs, I'd be looking to use 12mm minimum.

PS. i have another thread regarding my walls which know one seems to answer. i can only presume every one thinks i am to lazy to search previouse threads. i have read the wiki and hundreds of other threads and the solution seams to be tanking (what is this?) thanks in advance.

I missed your other post, tanking is a a paintable waterproof product that will provide you with a watertight surface on which to tile. It adds no strength to your wall. I have replied to your other post.

 

[Master of None]

Looks like 12mm WBP then. however i will not be able to have this under my kitchen unit legs but i will put this and the tiles under the plinth. does any one see any problems with this setup? it will leave the chipboard under the units vulnerable to water ingress in the event of a leak. is this a real problem it is MR caberboard. should i paint it with something?
thanks for all your help.

 

[JohnD]

do you have wind-up legs on the units? If so, it is often possible (with the help of a bit of wedging) to raise the legs enough to slip flooring underneath.

It is particularly useful to have the floor under your appliances level with the rest of the floor, so that you can pull them out

 

[gcol]

... it will leave the chipboard under the units vulnerable to water ingress in the event of a leak. is this a real problem it is MR caberboard. should i paint it with something?

It'll only be a problem if you spill something. Though the chances of that are quite high in a kitchen.
You could paint it with some exterior woodstain and varnish in one. Also, along the edges of the tiles (under the units) you could silicone down a length of timber to make a small barrier to any water that runs underneath.

 

[Master of None]

yes JohnD it is adjustable legs, and a new kitchen, however i am already close to there lower tolerance. The problem is modern house V units to the ceiling. Less cleaning (single man, pos rent out.) However its a good point. After checking again, i may be able to live with the ply but not the tiles under the unit legs. They are ikea units (no service space) so all pipework is exposed inside unit. so the only time i would need to pull them out is a stripout. Unless you can think of another scenario?

yes Gcol i agree. However the chance of me spilling any thing in my kitchen other than a can of larger is remote to say the least. i was thinking more along the lines of one of my pipes joints weeping which would be behind the unit anyway.

PS. I am a building services draughtsman. But fitting pipes, bricks, partitions, tiles etc is a lot more skillful than simply drawing them.......... i now really appreciate what the builders / decorators / plumbers accomplish on site now i have tried it for my self.