Some Advice For Tiling Kitchen

[Swindiff]

Hi
1st time post, newbie tiler after some advise.

I am planning on tiling the whole of the downstairs in a 3 storey townhouse, total area is around 30 square meters, have ordered 33 square meters of this porcelain tile. The room is kitchen / diner / family room, with a cloakroom and hallway.

Surface White

There has clearly been some water issues in the kitchen area in the past, as far as I can tell the floor is a concrete base (assumed as I cant see it) there is then a layer of insulation (polystyrene sheet), a DPM (blue plastic sheeting), then 18mm T+G Chipboard and then plywood (maybe 6mm thick).

I am assuming where there has been a leak in the past the plywood was compromised as it has been cut away (actually looks like it has been gnawed by a beaver) where it could be accessed in the kitchen area, however the ply still remains underneath the kitchen cabinets and in the dining area. The chipboard is also rotten around the sink area.

My plan is to remove the remaining plywood from the dining area, and where the cabinets once were (the kitchen has been removed). I then need to cut out the rotten chipboard with a circular saw and replace it.

I am then planning on laying 6mm Hardie Backerboard, this seems to be the best price I can find.

HardieBacker EZ GRID 6mm for Floors (HardieBacker 250) | Dry Lining | Plasterboard | Specialist Board | | Insulation Express

I have read that this should be laid on non-flexible tile adhesive and screwed to the chipboard. As the chipboard is 18mm and the backerboard is 6mm, the standard Hardie Backerboard screws at 32mm will be too long and puncture the DPM and Insulation so I was planning on using these screws which are 20mm

http://www.screwfix.com/p/turbogold-woodscrews-double-self-countersunk-4-x-20mm-200-pack/11191

The joints then need to be taped and skimmed with the same non flexible adhesive

http://www.diy.com/departments/ceme...6414!&ef_id=U853pAAABQH6jUcU:20160607105713:s

The porcelain tiles are then laid with flexible adhesive.

Have I got anything spectacularly wrong here?

Are those screws suitable, they seem to make a big deal about using the right screws, but then I guess they want to sell their product.

What adhesives should I be using, flexible and non-flexible.

Many thanks for any advise you can give.

Cheers

 

[Ian]

What is the chipboard fixed to? Sounds like a floating floor from what you've described.

 

[Swindiff]

Hi Bri, yes as far as I can tell its just sat on the DPM and Insulation. I will know better when I come to cut the rotten portion of the chipboard out.

 

[Ian]

Have a search on the forum for, floating floors, it's a heavily discussed subject and 95% wouldn't even entertain tiling onto one without some serious prep work.

 

[Swindiff]

Oh crap

Whats the solution, get it screeded?

 

[Ian]

Oh crap

Whats the solution, get it screeded?

In a word. Yes. Using a 12mm cement board might work but, it's difficult to know without seeing just exactly how much deflection is in the chip board. Not something I'd be doing, once bitten and all that.

 

[Swindiff]

How thick would the screed need to be, just simple cement sand screed or something else? If I take the Chipboard and Ply up I am estimating that would be about 25-30mm. There are a couple of areas where there are partition walls e.g. cloakroom, is it ok to cut the chipboard out around them and screed upto them?

 

[Old Mod]

If u have a cross hair laser, put it on floor and walk around it, u'll soon see the amount of deflection u have and its a good visual aid to show customer the problem.
Failing that a brim full glass of water can have same visual effect.

 

[Swindiff]

OK I have been and had a better look, there is a concrete base, on top of that is 50mm of bog standard polystyrene sheet, layer of thin blue plastic (think this is to stop the chipboard squeaking on the polystyrene more than anything else), then 18mm T+G Chipboard then 9mm plywood.

So total of around 77mm. Could I replace the 50mm polystyrene with 25mm Celotex, than add a screed of around 50mm, this will bring me to the same level. I understand recommendation for screed is 70mm, but I am assuming 25mm celotex wont flex as much as 50mm polystyrene, also would it help if I had screed with fibres added?

Or I could possibly go to 70mm screed which would raise the floor level by about 20mm?

Opinions on the best way to go

Cheers

 

[Spare Tool]

I'd be looking at lifting floating floor and either getting it screeded to desired height, or fitting marmox boards, available from 6-60mm, to concrete base.
Most cost effective is screeding for sure but you'll then have to wait for at least two months before its dry enough to tile on.
Marmox boards can be tiled on straight away..

 

[Swindiff]

2 month wait is ok. Just want to check that this floor construction is adequate

Concrete base - 25mm Celotex - 50mm screed with fibres

Should there be a plastic sheet separating the Celotex and screed, or does the screed just go straight onto the Celotex, does it need to be prepped in any way?

 

[Swindiff]

I'd like to throw something else into the mix now, underfloor electric heating 🙂

I guess this would go on top of the screed and tiled directly onto?

 

[Tile Shop]

I'd be looking at lifting floating floor and either getting it screeded to desired height, or fitting marmox boards, available from 6-60mm, to concrete base.
Most cost effective is screeding for sure but you'll then have to wait for at least two months before its dry enough to tile on.
Marmox boards can be tiled on straight away..

I'd like to throw something else into the mix now, underfloor electric heating 🙂

I guess this would go on top of the screed and tiled directly onto?

BAL Quickset cement can be added in place of normal cement if you wanna fast-track it. Going onto a polythene layer then Celotex to build up the level, would mean the heat transferring down 65mm of screed (minimum thickness of screed on a floating layer) before bouncing off the insulation so it will use extra power on the initial heat up.

So my opinion would be, Polythene layer, 65mm cement/sand screed (1:4 mix), 10mm Marmox, UFH, SLC, Flexy adhesive, tile, grout, finish!

But there are guys on here with more experience than me, that may blow my theory out the water and have a more suitable suggestion 🙂

 

[J Sid]

I'd like to throw something else into the mix now, underfloor electric heating 🙂

I guess this would go on top of the screed and tiled directly onto?

underfloor heating in the screed

 

[Swindiff]

Either in the screed or on top, open to opinions. Is there a need for a SLC if on top of the screed, I can see how it would probably make laying the tiles easier.

If I screed first then put insulation on top, rather than the other way round, would it be better to have a thinner screed, say 50mm and a thicker insulation layer, 25mm as doing it this way the screed is laid directly onto the concrete, not on insulation.

 

[Tile Shop]

The SLC is to go over the electric heating cables, not the screed (unless its really wonky). It a) protects the cables while tiling, b) encases the cables to get full heat transfer, c) gives you a perfectly flat surface to tile onto and d) easier to lift the tiles if you fudge up or have to replace any in the future........ This will differ if you use a system like Ditra Heat as they recommend tiling it directly without SLC providing you hit 100% coverage. But double check with the heating manufacturer for their recommendations.

If its a new screed it should be pretty level to begin with. Any minor imperfections can be overcome with adhesive when laying the insulation boards (as an example, Tilemaster Rapid Setaflex can overcome 12mm) , but again ensuring you have a 100% solid bed and no voids. If your floor is out by more than what it says on your bag about maximum depth, then yes you will need to level it first, before laying your insulation. Or you could consider switching to a PTB adhesive.

 

[Swindiff]

OK so thinking as I will be getting a new screed laid, an in screed system will probably work out a lot cheaper. I have about 75-80mm to play with. So 25mm of Celotex laid on the concrete subfloor. Heating cable attached to the Celotex. I have found this kit online which seems reasonable.
In-screed Underfloor Heating System
Screed with a 50mm thick fibre screed. Tile directly onto the screed. Would this be a legitimate method?
Does the Celotex need fixing in any way to the concrete subfloor?

 

[J Sid]

water fed in screed heating not electric

 

[Swindiff]

I have ruled water fed out, the electric will be much easier and cheaper to install.

 

[J Sid]

but not to run 🙁

 

[Swindiff]

I know it would be cheaper to run, but for my situation just to much of a pita to install 🙁

 

[Old Mod]

Look into this Schluter system, it radically reduces height of required screed, it's a wet system as opposed to electric. So although initially more expensive, far more economical running costs.
Sounds ideal for your situation.

Underfloor Heating System | Schlüter-Systems

 

[Swindiff]

That does look interesting, cheers. I have emailed them to find out prices, am dreading what they will come up with lol

 

[Swindiff]

Electric it is then lol. Over 4 grand for that system. About 10 times the price of in screed electric heating. No way I could justify spending that sort of money on it. Cheers anyway.

 

[Swindiff]

So all the flooring is now up. I can manage to get in 50mm of insulation and 60mm of screed. Just wanted to check my plans with guys in the know that may have done this before. Floor is block and beam construction rather than a poured concrete base, see image.

20160610_160600.jpg

Lay a DPM over the block and beam concrete floor, leave plenty up the walls
http://www.screwfix.com/p/dmp-damp-proof-membrane-blue-1200ga-4-x-15m/98181

Lay Celotex 50mm insulation. Which should I use? The most common seems to be Ga4000, but I have also read that Celotex tuff-R GA3000 is suited to underfloor heating (fibres to give extra strength) is this necessary?

Tape all the joints in the Celotex, should I use the proper celotex tape, or are you just paying for the name, will general aluminium tape do?
http://www.screwfix.com/p/aluminium-foil-tape-silver-aluminium-50mm-x-45m/35529?kpid=35529&cm_mmc=Google-_-Product Listing Ads-_-Sales Tracking-_-sales tracking url&cm_mmc=Google-_-Shopping - Sealants and Adhesives (New)-_-Shopping - Sealants and Adhesives-_-all\sealants & adhesives\building tape\other_0b0f1183-7209-23c9-8a5c-00002313f16a&gclid=CjwKEAjwkPS6BRD2ioKR7K245jASJAD1ZqHOwglYCwBthe_QmnNWDnuyPa-DmMD9uiwBIE3sBtEq0xoCblTw_wcB

Should I have another sheet of plastic here. I have read a 500ga seperation later on top of the insulation is a good idea?

Install the in screed heating system. I have come across a few (3 links here), which is best, or are they all much the same?
In Screed Underfloor Heating | Underfloor Heating
Warmup Inscreed Heating
In Screed Underfloor heating Cable Kits

Install expansion foam around the walls to allow the screed to expand when heated
http://www.screwfix.com/p/jg-speedfit-jgufhedge-edge-insulation-roll-25-x-0-15m/87019?kpid=KINASEKPID&cm_mmc=GoogleLocal-_-Datafeed-_-Heating and Plumbing&cm_mmc=Google-_-Shopping - Heating and Plumbing-_-Shopping - Heating and Plumbing-_-all\heating & plumbing\underfloor heating\jg speedfit_0b0f1183-7209-23c9-8a5c-00002313f16a&gclid=CjwKEAjwkPS6BRD2ioKR7K245jASJAD1ZqHOpfLRoCrQPy8A9imbo_FBMaDvSlz_--hDk3nuQ1euJRoCyw_w_wcB

Screed over up to a level of 60mm. I will be installing a fiber screed for added strength for expansion and contraction of the heated floor.

Am I missing anything, any tips?

Cheers

 

[Swindiff]

Don't know why my photo links are not working. Tried one from google drive and facebook

Edit: Posted as a link rather than an image seems to work

 

[Swindiff]

Also considering something like this, really depends on what the guy who is changing my boiler says. Wondering if the pump will fit in same cupboard as the boiler and if it will how quiet it is.

ProWarm™ Standard Output Water Underfloor Heating Kit - Standard Output Kits - Water Underfloor Heating

Polypipe standard output single zone kit

 

[Swindiff]

This is what I have come up with for the Polypipe system. Any obvious errors?

Kitchen Area (Screed and UFH Radius).jpg

 

[Swindiff]

Should I post this in a different forum, its more underfloor heating at the minute rather than tiling?