Preparing my walls for en-suite

[chriselevate]

Hi guys,

I'm ready to start my en-suite and considering the length of time and problems I had doing the minor job in our master bathroom (some of you will have read all about that) I thought I'd ask for advice first before I drive in and make a hash of it! lol

Right... here's the plan. I've drawn a diagram to give you an idea of what I'm working with and the plan of action to stop the damp coming through our solid construted walls of our 65yr old house with no cavity.



The walls are cleared and back to brick by the way and the skirting boards are all off. The intention it to tile the whole shower enclosure area and fit a tray and shower screen we bought from bathstore. I'm only tiling this are plus some splash back areas beacuse the tiles are expensive and the ceiling in our old house are so high.... therefore costing a fortune! The intention for the floor is to tile it.

I'm go a big roll of Oldroyd P membrane (http://www.safeguardeurope.com/products/oldroyd_p.php) and have used it a few of our bedrooms. It works really well and has fixe many of our damp problems caused by having no cavity wall. I use it with the dot and dab technique and apply 10mm plasterboard to the membrane before skimming with multifinish.

In the areas where the showers going should I use a different board? Should I be skinning with multifinish the shower enclosure walls? People have mentioned tanking? I'm guessing that this shower enclosure area will need tanking in some way or another to create a good water tight finish?

Thanks

 

[dextrous]

Okey dokey, and off we go!

First, if this is a new use of a room, then it requires building control approval, and you should contact the local office for clarification of what is required.

Any wiring (including lights, extractor fans, and possible earth bonding) should be installed and tested by an electrician with the relevant qualifications. Etc etc. So, enough of the legal advice and back to the matter in hand!

Can't comment on the Olroyd, since have never used it. However, with regard to the plasterboard (this post should really be on the plastering forum), use moisture resistant board, which can be skimmed once it has been coated with an approved primer.



Within the shower area, there are two choices available. If you go for plasterboard, then this does not need to be skimmed prior to tiling (although there's no harm in doing so), but it will need to be tanked as you say - most people on here go for BAL tanking products which is primed and painted on and dries quickly.

The other alternative would be to use a cementious board such as Aquapanel. This is usually fixed into place by screwing into studwork or battens attached to the wall, or (more likely in your case) by dot and dabbing it, letting the adhesive set overnight, and using frame fixing plug/screws which are drilled through the places where the plasterboard adhesive d&dab have been positioned. This board should not be skimmed and can be tiled onto directly with no further preparation other than taping the joints and corners. Although the boards are dearer, the overall cost is about the same as for tanking.

As for your ceilings being so high, there is no reason why you should not lower this with a simple studwork frame, which would enable you to install a ceiling (in-line) extractor fan, and add insulation to the room.

With regard to any pipework that needs to be completed - personally I prefer copper with soldered fittings. However, plastic pipework is fine and will enable you to run complicated bends considerably more easily. However, joints need to be accessible, and I would advise you to buy a roll of pipework to minimise the number of them required.

You clearly have had experience with tiling, but again I'd advise the use of powdered adhesive appropriate for the tiles you intend to use - BAL is again a highly regarded product.

So, now you have a starting point, and I look forward to viewing your progress. It will be worth your while putting separate posts for individual issues on forums where specialist within these fields mostly "reside"

 

[chriselevate]

Hi Dextrous,

Thanks for your post, reply and thoughts.

Let me start by saying.... the room in question is one that we've gutted so everything is in place for the new en-suite. In other words.. planning permition and electrical stuff would already have been done some years ago. The reason we're re-doing the room is that it was dam, dirty and horrible beacuse the previous owner obviously did the job cheap and it was a bad job!

The shower connections, wiring and plumbing are all in place, there's an extractor cut into the wall already and the connection for all the other wiring and sink are all there in place.

I don't wishto reduce the height of the ceiling as I want to make it look as big, open and airy as possile. Reducing the height will make it look and feel small and pokey.

So all I need to know, for now, to get me started is.... can I simple do this.... dry line the room as I have done in other rooms using my membrane follwed by normal plasterboard? i.e. not having to change the type of board from plasterboard to another type for the shower area?

It looks like your saying the next step is then to apply the tanking to the shower area. How is this applied? Is it simple like gluing a membrane to the plasterboard?

I can the plaster every wall making sure I don't polish up the area that will be tiled?

That's probably enough questions for now.

Cheers

 

[gcol]

Within the shower area, there are two choices available. If you go for plasterboard, then this does not need to be skimmed prior to tiling (although there's no harm in doing so)...

Skimming plasterboard reduces the weight that you can effectively support on it.

It looks like your saying the next step is then to apply the tanking to the shower area. How is this applied? Is it simple like gluing a membrane to the plasterboard?

It's painted on - dead easy to do.

 

[dextrous]

gcol has provided you with some details. The plasterboard in a bathroom should be Moisture Resistant, as advised in my previous post. The difference in cost between this and standard board is minimal, and it is best practice to use it in humid environments. If you decide not to, it's not the end of the world, and will make skimming over cheaper as you don't need to buy the special primer required for it.

If you are tiling over the whole surface or up to dado height, then skimming is not needed beneath the tiles, and gcol indicates that it would be disavantageous to do so.

Tanking and related information can be got here amongst othe places

 

[dextrous]

PS - personally I prefer to use 12.5mm board and not 9mm. Others may differ in opinion. One of the better posters on here regarding plastering (especially bathrooms) is RichardC. Hopefully he'll come on board here and offer more fully rationalised details.

 

[chriselevate]

So in other words I could use bog standar 10mm plasterboard and then skim all the areas except the area where it'll be tiled. Then in the area where I'm tiling I should be using the BAL WP1 Waterproof Shower Kit which is quick and a easy to paint on prior to tiling? Does it take long for this to go off before tiling?

Thanks again for your help chaps!

Added...

Just read your latest post suggesting 12.5 rather than 9mm.... be good to hear the rational behind this.

I was going to use the 9mm stuff as once I've used the membrane and boarded over it I'm quickly running out of width to fit the shower tray. I guess one solution would be to cut a hole in the plasterboard wall marked 'D' on the diagram above. That way I can slde in my stone resin tray I bought from bathstore if it doesn't fit? Or would you suggest not doing this from a water tight point of view?

Thanks

 

[dextrous]

So in other words I could use bog standar 10mm plasterboard and then skim all the areas except the area where it'll be tiled. Then in the area where I'm tiling I should be using the BAL WP1 Waterproof Shower Kit which is quick and a easy to paint on prior to tiling? Does it take long for this to go off before tiling?

Yep to the plasterboard, and a few hours or overnight for the tanking

Just read your latest post suggesting 12.5 rather than 9mm.... be good to hear the rational behind this.

Is just more substantial to work with and (in my opinion) doesn't tend to flex so much when you tap it flat onto the wall

I was going to use the 9mm stuff as once I've used the membrane and boarded over it I'm quickly running out of width to fit the shower tray. I guess one solution would be to cut a hole in the plasterboard wall marked 'D' on the diagram above. That way I can slde in my stone resin tray I bought from bathstore if it doesn't fit? Or would you suggest not doing this from a water tight point of view?

Nothing wrong with the board resting on the tray - just make sure you apply silicon between the tray and the edge of the board before you tile as well as after, since, should any water permeate behind the tiles via any hairline cracks that may appear the grouting in due course, you don't want this slipping down the back of the tray nor getting into the plasterboard behind the tanking, especially if it isn't MR

 

[chriselevate]

So does the tanking need to be applied from top to bottom of where the enclosure is going?

It doesn't matter if I cut a hole in the current plasterboard at the bottom of the wall 'D' and slide the tray into this hole? You would apply a good fix of silicone before tanking and the finally tiling down to the tray then.

The tray will be say on the floorboards.... do I need to do something to the floorboards before I sit the tray down on the floor? The floor boards will eventually be tiled in a different tile to the wall tiles. There's something I need to do before I tile on these isn't there?

Thanks

 

[dextrous]

Refer to the instructions for details of the tanking - use the link in my previous post to get you on your way.

As for the tray, it is usually a requirement to bed this on a wet mortar base to ensure maximum support over the entire base and provide a way of levelling it precisely (using a spirit level around the perimeter, and tapping it gently with a rubber mallet.) Prime the existing boards with PVA, and use a 3 or 4 parts sharp sand to 1 part cement by volume, quite wet (add a bit of plasticiser or even washing up liquid since it makes it easier to work with), and run ridge lines as with bricklaying to provide room for the mortar to spread out while you position and level the tray. Leave overnight before you stand on it.

The hardest part about the whole operation is getting the trap and wastepipe in place. Plan ahead and do a dry run before you lay the mortar

As for preparing the floor for tiling, in the ideal world you would remove the existing floorboards and replace then with 18mm or preferably 25mm wbp ply. If this isn't feasible, then screw 12mm ply over the whole surface to ensure that you have a level surface to work on, and which will also reduce to a minimum any flexing since tiles don't like this sort of behaviour one little bit!!

 

[Richard C]

Don’t tile onto the floorboards, it’ll almost certainly be doomed to failure. My preference is to always take them up & replace with 18mm or 25mm WBP, depending on individual circumstances as this keep the original threshold either the same or within reasonable height limits when tiled. If you overboard, use min. 12mm minimum as advised but screw it through INTO the joists below & not just onto the surface of the boards & position any major board joints down the centre of a joist; make sure you know the location of any pipes or screws first . The problem is that over boarding, IMO, gives an unacceptable height difference at the threshold.

I always use 12.5mm PB on walls not 10mm & always MR in bathrooms. I would say it’s even more important in your case with the damp issues even though you have the membrane fitted. You must tank the wet areas & use only high quality trade products for the tiling not the cheaper DIY stuff.

 

[chriselevate]

Hi Richard,

Thanks for adding your comments.

With the room having already been split off from the main bedroom (as in... it was one big room but the previous people partitioned it off) the floor boards run the whole length of the room. I think this will be very difficult and time consuming to pull up all the existing floorboards in order to prepare for tiling. I know it's not idea but I think I'll have to use the 12mm WBP exteior ply and srew it down as you described earlier. I know the treshold will be 2-3cm higher but it's something that can't be helped in this instance.

So should I be looking to fit ply all the way accross the floor.... i.e. even where the shower tray is fitting? And then simply cutting out a whole in the ply where the waste trap comes up to attach to the bottom of the tray? The floor boards in this part have been hacked around quite a lot as obviously the person who fitted the last tray had several of them up to fit the waste pipes etc.

You go on to talk about 12.5mm PB on the walls and say you use MR in bathrooms. You're talking about using this on ALL of the walls rather than changing plasterboard type for just the shower enclosure? What borad is this? Is it the Vapourshield PB that wickes sell here.... http://www.wickes.co.uk/Vapourshield-Plasterboard/invt/220230 if so is there a 12.5mm version of the one I've just posted?

One last thing... the shower tray we've bought is a bathstore one. It's flipping heavy! Do they ALL need to be set on a concrete base? Or is it only the cheap and nasty flimsy ones that do?

Thanks again for your help.

 

[dextrous]

Nope - MR board is like this
There are several manufacturers (including Knauf). B&Q and Wickes don't stock this the last time I looked, but building centres do. Although it is wiser to use this on all the walls, around the wet area of the tray would be considered a desirable minimum.

With regard to the tray - the mortar is there to ensure maximum support and to assist in levelling it, as I indicated previously, and is used on both heavy and light trays. The instructions that come with the tray normally provide details.

There will be no need to use ply under the shower, and doing so will make it harder to fit the trap since there isn't a very long neck beneath the trap and the ply will set it high above the space between the joists, plus actually getting your hand under there to tighten the pipe onto the outlet will be nigh on impossible.

Also, the extra 12mm of ply on the outside will make an even smaller step up and over into the tray - which is a good thing, whilst also adding additional cover over the mortar bed which will raise the tray up due to it's thickness (about 10mm by the time it's compressed)!

 

[Richard C]

Given the option I always use a cement based tile backer board such as Aqapanel in wet areas but the MR will be OK as long as you tank before tiling. Many of the larger B&Q trade outlets now stock a wider range of PB including MR & Soundblock so it’s worth checking.

Stone resin trays are relatively brittle & the main role of the weak mix base is to ensure the tray is fully supported without any stress points that could cause it to crack. It’s a requirement of many manufacturers’ warranty conditions; acrylic or fibre glass trays can be supported on a bed of silicone. Use a soft sand/cement mortar mix not concrete & the bed only needs to be thick enough to provide support, it should only raise the tray 5mm or so, well below the thickness of the floor tiles.

Personally I would run the ply under the tray as it will provide a nice firm, flat base to bed the tray onto. I would still consider taking those boards up; it’s not that much hassle even when the boards dive under the wall, it will make a significant difference to the rigidity of the floor & the ultimate longevity of your tiled floor.

 

[chriselevate]

Brialliat... thanks for your replies guys.

Really appreciate them.

I'm still digesting all you've said and am getting my head around your tips and tricks. One question would be.... If I take up all my floorboards.... how would I be able to do this? I mean what tool would I use to get right into the wall sections? And wouldn't it be a weak point if I can't get the new board to fit exactly on the joist for the last bit that I put in?

Cheers