Hello all,

I'm about to buy the boards I need for the kitchen and bathroom tiling, but I'm not 100% which ones to opt for, any advice would be very gratefully received!

Firstly the bathroom. The wall tiles we're using are marble and too heavy to go directly onto the existing plaster skim. So, I need to get some tile backer boards. The room is 27mm wider than the shower bath we have. We've been debating which to get and how best to fix them.

A few questions...

1) Is it better to put the boards on before the bath is plumbed in so the bath fits snugly between the boards and there is no gap?

2) Would doing the above be impossible ,as getting an accurate thickness with the adhesive would be difficult?

3) Or is the best idea to put the bath in and then try to fit the tile backer boards closely to it?

4) The long side of the bath that will be against the wall has a vertical lip on it to reduce the chance of water getting through, does this make any difference?

5) If the boards go on first, is it better to fit them all the way to the floor so they have optimum support from below?

6) If boards first I assume the adhesive would mean the 27mm gap would be insufficient for 12mm boards at both ends of the bath. Would 6mm be enough on the end beneath the window where there is only about 18" height, so it wouldn't be taking as many tiles?

7) I was planning on 12mm hardiebacker, but I've just noticed the GTEC Aqua Board. Are there other suitable products? Which boards are best?

8) I think I need adhesive and screw fixings? Mapei seem to be highly recommended, is this best and if so which of their products do I need?

9) Any particular screw fixings? For the knauf aquapanels we used on the floor we eventually opted for galvanised screws and nylon washers as we couldn't find their fixings.

10) What thickness of adhesive should we be aiming for?

11) Is there any reason to use their own brand fibreglass tape between panels? We have another brand left over from the floor?

12) Should we leave gaps between panels and fill with adhesive or butt them up tightly to each other?

13) Whilst I'm shopping, what's the best sealant to use?

Sorry for the absolute barrage of questions. I'm a bit of a perfectionist and want to make sure I get this right first time. They're expensive tiles and I don't want to be pulling them down and starting again!


Going onto the kitchen... I thought it could make sense to buy everything at once, so...

It's a 1950s house. The floor is concrete and I think it's screeded - we've yet to pull up all the layers of grotty lino tiles. (Fingers crossed that the floor is good enough to not need further prep.) We're planning on having underfloor heating below 40cm2 calibrated slate tiles. We want it adequately insulated, with the minimal excess height. It The adjacent room will have a solid wood floor, which I think means 18mm boards glued down. I don't think we can avoid some difference in height, but the less the better.

1) Which adhesive is best below the insulation? And how thick?

2) Which insulation boards are most effective? Marmox? Celotex? EkoBOARD? Something else?

3) What thickness do we need to use? My guess is 10mm.

4) From reading on here it sounds like we lay the underfloor heating mat on the insulation, then use a self levelling compound. Am I right? Which SLC do you recommend?

5) Should I be using a DPM or decoupling membrane or anything else?

6) Lay tiles using a flexible adhesive? Again, which is best? And how thick should it be?

7) We're considering laying the tiles ourselves, we have no experience. Is this advisable, or are we likely to make a mess of it and regret it? I'm expecting this floor to have a long lifespan, so want it to look good, and be level enough to have furniture/units above. Would you advise using a professional despite the expense? (The total area is 20m2, so not cheap to say the least.)

8) What grout would you recommend?

9) How wide should the grout gaps be?

10) Do we need to use sealant? Pre-grouting? After? Both?


Thank you in advance or your help, it really is hugely appreciated.

Alice

dear me lol

i would go for wedi board,,,many thicknesses, higher weight rations than backer boards, better thermal values,
you can use their 50mm for weight bearing application ie steps, seating in wet areas etc. you can box in your bath and pipes with it too...its also nearly 100 perc water proof

thats the answer to some of your questions

ed

yes, insulation boards, then ufh, then self levelling compound...this is the best way to do it

Thanks for Your reply Ed, though I'm still confused.

The figures I've found indicate marmox and wedi have identical insulative properties. Since posting I've found 'Heatstore Tile Backer boards', not to mention 'Fastwarm', 'Blueboard', and 'Aquapanel TH', all of which claim to be even better in terms of insulation. As the primary purpose of the boards in the kitchen is insulation, why not one of these to use in there?

The boards in the bathrooom are needed primarily for their ability to hold the weight of the tiles, water resistance also being an important feature, so it sounds like wedi board could be the best option here. What thickness would I need to use? It's only a small bathroom, has virtually no exposed pipes and the bath came with a side panel, so I don't get to play with tiling it in. It will just be used under the wall tiles.

Cheers.

You're right, the blue boards (sometimes yellow) do have the SAME thermal and compression values as the marmox type boards. I'd use them myself due to their price. They need slightly more respect during the installation of the matting but once you've got your SLC down you're laughing all the way to the bank with your savings.

They're only suitable on concrete and screed.

Thanks for the huge post but I'd have considered the second question 1 to be question 14 to save any confusion.

Very good point! I'll edit them now.

Seems my essay has scared everyone away.

So, to make it simpler...

I think I'll order wedi or marmox 12mm for the walls, possibly including a small section of 6mm. (Uheat have marmox.)

Then get a cheaper insulating board for the kitchen floor. Maybe blueboard, or Uheat do one called Ekoboard which is only slightly less insulating. As they're a sponsor I might give them a call.

The other immediate question is whether to put up the boards or plumb in the bath first. If boards we need to do it asap, but we disagree on that point...

Any probs with what I plan to buy, and advice re:bath/boards would be very gratefully received.

Cheers all.