Wet room Preparation

[Ziggy1979]

Hi

We want to prep our bathroom for tiling - we will be making it into a wet room - and I have a few questions. Please bear with me and please please help. :)

For the flooring, can aquapanels be screwed directly onto timber joists or do they need to go on the existing wooden flooring (or a new ply/MR chipboard sub floor)? The reason is that we are having electric UFH and want the insulation benefits of the aquapanels but want to keep the floor level as low as possible to not have a massive step into the landing. As we understand it we need:
1. An insulated board (eg aquapanels)
2. UFH cable
3. Self levelling compound
4. Schluter Ditra matting with thin set
5. Tile (with thin set)

If we can get away with only aquapanels, how thick should they be and should they be level with the wet room shower former (or can we level this off with the self levelling compound)?

Also, I've read some posts saying that the walls should never be made of ply or plasterboard (of any variety) - which makes sense. But the I read other posts saying that with tanking membranes (eg Schluter Kerdi) it no longer matters what the walls are made of. Because of the cost saving of PB/ply vs cement boards/tile backers is this true or is it best to pay a little more and stick with the safest option?

Thanks again for all your help!

Zigs

[royaloakcarpentry]

That is a lot of uncertainty and questions for a person who is going to do a wet room.

You can use every gucci material and tool on this project but if you are inexperienced, it will end in failure. Just to warn you.

I commend you on doing the research. A lot of what you have discovered is mainly down to opinion, big manufacturers sponsoring trade organisations etc and internet waffle (and like all subjects on the internet from cars to health, there is a load of complete 5hit which some people digest and believe).

The type of material needs to be considered in an entirely different way for a wet room than a shower/bathroom.

The type of material needs to be considered in an entirely different way for a wet room than a "wet room" with a shower screen.

What will the set up be?

[Ziggy1979]

Hi Royaloakcarpentry...

...and thanks for taking the time to answer.

In terms of setup, I'm guessing you mean the finished bathroom layout?

The shower area will be in a corner of the room with a glass screen on one side. We're still not sure whether or not to have a door. If we can make it 1200mm+ long then we might not. Otherwise we probably will as we are thinking of a pumped power shower and don't want the bathroom getting wet.

For the shower area I'll be using a wet room former with a linear drain (the ones that drain in one angle and make tiling easier by avoiding mitring, etc.). I'm confident that I can fit this with noggins and plywood underneath as I've built new floors and replaced joists before. However, the price seems to vary massively between known and random brands. Is there any advice you can give when choosing a former? It's not always the case that the most expensive is best. I will certainly not be trying to make my own run off to a drain without a former at this stage as I think I've got enough to learn on my plate! :)

The rest of the bathroom will include a wall hung unit with drawers and sink (I've made and hung these successfully for a few years now at home and friends, etc), standard bath with tiled side and end and a wall hung toilet (probably on a grohe concealed frame and cistern as I fitted one in our existing bathroom 7+yrs ago with no problems so far) (let's hope I didn't just curse it!). :)

The bathroom will be fully tiled (ie floors and all walls to ceiling).

Thank you for the heads up re inexperience. I have done a lot of carpentry and building work before so far without any real, certainly major problems (we all make mistakes but none have been irreparable problems), but I do hold my hand up that this is the first wet room and tanking work I will do. Tbh, it's the reason for the extensive questions, etc. I have a good idea of what to do but would rather ask and stand corrected than go in there thinking I know it all just fine. Also, there's a lot to be said for experience eg some products are easier to install than others even though they seem similar to another brands products, some seem similar but aren't quite as good (eg my opinion with Blum v Hettich soft close drawer runners), some products have shortcomings which become very apparent with continued use, etc. and those are insights that experienced guys like yourself can provide.

So again, thanks so much for your response. If you can please make any suggestions that would help me not fail I would be very very grateful! At this stage I am still researching products, techniques, procedures, etc so I'm still a couple of months before being satisfied that I can go in there and get started. I like to plan, then plan again, etc. (although this might make me a regular pest on the forum!) ;)

Thanks again!

Zigs

[darrenba]

Any reason for why you want to have a wet room former and not go for a low profile shower tray? Is this ground floor or 1st floor?

[Ziggy1979]

Hi Darrenba

We want to tile the floor and shower area in the same tile rather than have a shower tray. We'd also like to have it at the same level ie no step dividing the shower and the bathroom floor.

The bathroom is on a first floor (timber joists).

Thanks for posting!

Zigs :)

[darrenba]

Well generally I would talk any customer of mine out of creating a wet room on a timber floor - there is to much opportunity for things to fail. I'd go for a low profile tray and then with your requirements for underfloor heating that would be up to the level of a tray anyway, so no step at all

[Ziggy1979]

Hi Darrenba

Thanks again for your advice.

How come you advise against wet rooms on timber floors? I understand that a poor choice of materials and workmanship will cause big problems but to a greater or lesser extent this is always the case. I thought that if installed properly (and I'm not saying that despite my best efforts I won't screw it up!) it should be just as watertight as using a shower tray?

I thought the formers are basically shower trays that you tile on. IF that's the case is there any real difference in the risk of leaks over the tray you suggest? Basically what I'm assuming is that the leaks are most likely to happen around the edges of the former, but wouldn't this also be the same with a tray which has tiles up to the same level? Or does the lip/step around the tray provide a substantial improvement in the risk of leaking?

Also I'm not trying to be arsy or ungrateful, i just want to fully understand the risks/benefits of shower tray v wet room (when both are properly installed). It seems that pluses for the tray are that they seem to be easier to fit, have less margin for error and are cheaper (but its not the look we'd like a arghh d@mn aesthetics!) :)

Thanks again

Zigs :)

[Colour Republic]

Hi Ziggy,

just a few questions... What type of tiles are you thinking of using on this project (in the main area and on the shower former)? and what is your reason for using ditra? is it as a waterproof membrane or as a decoupling membrane?

[Ziggy1979]

Hi Colour Republic

We haven't decided on the actual tiles but are leaning towards largish marble (possibly Marfil with a dark brown marble in some areas to break it up or, alternatively limestone). That said, we might well go with ceramic if we find one we like.

Whichever way we go we'd like to use the same floor tiles throughout, including over the shower former.

I'd thought to use the Ditra as a decoupling membrane over the SLC with the former, backer boards and waterproof tape providing the tanking (and insulation) under the UFH.

Just realised...how risky/dangerous is it to have the UFH wires under the SLC and decoupling membrane without tanking (ie should I also tank the Ditra)?

Thanks for your help!

Zigs :)

[royaloakcarpentry]

You need to make sure that the flex is taken out of the joists.

If using ply to cover the joists, ideally you want 25mm ply. Seal both sides and all edges. Secured at 300mm intervals (personally, but I think the standard is 400mm).

Tile backer board then goes down.

Underfloor heating (make sure it is on an RCD protected circuit and you may need an electrician to make alterations and certificate to ensure this happens).

SLC can then go down. Make sure the underfloor heating wires are well secured down or they will float to the surface of the SLC.

I have ommitted fitting the shower former, as you know when you are doing this in relation to the above stages.

I would tank the floor complete and lap it up the walls. Tank the shower area walls and extend it out 600mm past any glass screen or to where the shower will reach, when in use.

There are tanking kits which are DIY and not so confident orientated. personally we use Impey products which are a fap to work with and come in sheet form.

Make sure than any doorway is sealed against water encroaching under the door to another room, if applicable.

[Ziggy1979]

HiRoyalOakcarpentry

Thanks again for posting and many thanks for your advice!

I'm especially grateful re the floating UFH wires - that's something only an experienced person can make you aware of and certainly hadn't crossed my mind.

Is it worth adding more noggins to the floor joists to make them more rigid or will the ply (WBP?) take care of that?

Do you recommend screwing or using tile adhesive to fix the tile backer boards down especially if using them for decoupling. Also, is 6mm thickness sufficient?

The impey self adhesive tanking kit seems the easiest to fit of the ones I've looked at so that's one decision made! :)

On tanking, I will be dry lining the walls with tile backer board for the whole bathroom (no PB). Is it ok for tanking purposes to seal the joints and corners of the backer boards or is it best to fully tank over them all with the Waterguard (ie overkill to do both or necessary/advisable).

Thanks again for all your help!!!

Zigs :)

[haveagohero]

A lot of what you do will depend on how thick the former is you will be using.

In general: noggin out the joists, 25mm WBP glued and screwed to the joists, backerboards, UFH, SLC (although you don't always need to SLC), membrane (make sure its lapped up the walls by 300mm minimum and for god sake don't cut the corners to fold them), prime then tile.

With the walls you will be better off with a cement board but follow manufacturer instructions for installation, most cannot be dot and dabbed and require a framework for the boards to be screwed to, tape the joints and coat this with rapid setting tile adhesive.

I would strongly urge you to re consider doing this job yourself, a small tear in the membrane, especially in a corner and you will have spent a lot of money to have to rip it out to find the leak, it doesn't sound like you have done much if any tiling and tiling with marble is difficult enough without laying it in a wet room you have constructed yourself over UFH.

Bed the backerboards into a solid bed of adhesive and screw it down as well, cement boards are not designed for uncoupling
In the UK we use tile adhesive not thinset

[darrenba]

Here's a link to some info on wet rooms that you may want to have a read of too

http://www.islandbathrooms.co.uk/blog/t ... -wet-rooms

[Ziggy1979]

Haveagohero and darrenba

Thank you both for your posts. Haveago thanks for the info even tho you feel I'd be better served by not trying to do it myself. I've seen many posters refuse to give info purely because they don't feel the op can do the work and either refuse to give any info or (worse) joke or insult the op.

I am grateful for your concerns. Tbh I do think I can do it and I'm really not just saying that. Like I've said this is not something I've done before but I have done a lot in the past which many advised against doing. I am competent and confident so as long as I am well informed and careful I know I can do it - so thanks again for everyone's help so far. I don't like to assume so if I ask many questions (even seemingly obvious ones) it's because I'd rather second guess myself or be put right that assume I am right (can't be too careful)! :)

Impey certainly seems to be the way forward - although by far not the cheapest. Their products seem reliable, offer v gd warranty and seem among the most straight forward to work with. I think planning, care and patience will pay dividends too which is why I'm still a couple of months out from starting.

You mentioned the membranes getting damaged - are they very delicate? I will be anally cautious about handling, installing, cleaning/prepping, etc (I am with everything - everyone tells me I'm major OCD which other than making me go a little slower shouldn't be a bad thing - right?).

I would have rather tiled over the UFH without the SLC for step/height into the hallway but given my inexperience tiling i think it will make tiling easier if I use an SLC. It also means less chance of me or anyone else damaging the UFH wires.

I've heard others say marble can be hard to tile. Is that because of its weight or are there other things I should be aware of? I'd heard some ppl recommended "buttering" tile adhesive on the back of (smooth) stone tiles like marble as well as on the wall/floor - do you guys recommend doing this?

Lastly, if using ply (screws 300mm) +backer boards (adhesive & screws) + SLC +tiles do I not need to use a decoupling membrane - that was the reason I had looked at the Schluter Ditra.

Thanks again!!!

Zigs

[royaloakcarpentry]

Impey certainly seems to be the way forward - although by far not the cheapest. Their products seem reliable, offer v gd warranty and seem among the most straight forward to work with. I think planning, care and patience will pay dividends too which is why I'm still a couple of months out from starting.

You mentioned the membranes getting damaged - are they very delicate? I will be anally cautious about handling, installing, cleaning/prepping, etc (I am with everything - everyone tells me I'm major OCD which other than making me go a little slower shouldn't be a bad thing - right?).

I would have rather tiled over the UFH without the SLC for step/height into the hallway but given my inexperience tiling i think it will make tiling easier if I use an SLC. It also means less chance of me or anyone else damaging the UFH wires.

I've heard others say marble can be hard to tile. Is that because of its weight or are there other things I should be aware of? I'd heard some ppl recommended "buttering" tile adhesive on the back of (smooth) stone tiles like marble as well as on the wall/floor - do you guys recommend doing this?

Lastly, if using ply (screws 300mm) +backer boards (adhesive & screws) + SLC +tiles do I not need to use a decoupling membrane - that was the reason I had looked at the Schluter Ditra.

Thanks again!!!

Zigs

Impey is a good product. There are many paint on membranes which are better suited to DIY. I can't comment on these because I use Impey.

Nine of the membranes are delicate. If you have a problem and have to remove a/some tiles, that is when the trouble will start. This will wreck it and this also applies to backer boards.

You can tile direct onto UFH, but thgis is not recommended. The reason why most will use and SLC first is because there is lots of opportunity to damage the UFH wires with a tiling trowel.

Marble is more hassle to cut than ceramic or porcelain. It needs cutting on an electric cutter. You need a good quality marble from around the £100/M2 mark. Don't get fooled by the 5hit that B&Q push out. Topps do a prestige marble which is £50/M2 but it varies in thickness and plenty of extra needs ordering to compensate for the tiles that break when bedding in or cutting.

Back buttering is something that is common to all tiles once a certain size is being used. The back of the tile if it is deeply ribbed will require it to be back buttered. I normally back butter all stone and porcelain tiles. Tiles that are 'bowed' will also need to be back buttered over part of the surface to compensate for this.

You won't need a decoupling membrane. They are for expansion. If the floor is not stiff enough, you will not have expansion but instead have deflection. There are no products for deflection, apart from possibly using the American method of incorporating chicken wire.