Getting Upstands Right In Alcove

[gmt1981]

Hello all,

Right...the Wife and I have just bought a right old project so funds are low, so I am trying to do what I can wherever possible to save costs. I will get the pro's in to do the tiling and plumbing but would appreciate some help to ensure the job is prepped properly prior to getting them in.

The room in question is an ensuite which was retrofitted using a stud wall set-up. As per the photo below I have installed 6mm backerboard to the floor and 12mm backerboard to part of the alcove where the shower will be situated.

As you can see space is pretty critical even using a 760mm square tray. Much to my frustration, as this is not highlighted anywhere on plumb center or Coram's website, the tray is in fact 775mm wide which has all but removed any chance of dot and dabbing the backerboard onto the solid brick wall.

This leads to my first question - what would be the best way to fix the board to the wall? Perhaps using some marmox washer type fixings or would standard hammer fixings suffice?

Next issue is the upstands...

As the bottom of the coram tray is ever so slightly wider at the bottom than the top, the upstands sit proud of the wall by ca. 6-7mm, meaning at least an adhesive bed of 10mm would be needed for the tiles to lead correctly down onto the upstand. I now know that upstands can (or is that 'should') be recessed into the wall but this is not an option as the backboard is firmly glued at the joins, so can't really be removed without making a right mess.

Looking at the photos below, would you say a tray with upstands is not going to work? Should I take it back and go for a normal style tray, even thought I thought the upstands would offer a belt and braces solution?

Apologies for the epic, but any advise/tips would be gratefully received!

Many thanks in advance
Graham

 

[Dave]

The upstands on the tray should normally be recessed into the wall.

 

[CJ]

Cut the backer board at the back and on the left, & recess the tray......which should give you enough room to baton out the right hand wall to fix the Hardibacker too.

Or just change the tray.

 

[gmt1981]

Cut the backer board at the back and on the left, & recess the tray......which should give you enough room to baton out the right hand wall to fix the Hardibacker too.

Or just change the tray.

Thanks for the advice. However, cutting the backboard would only give me an extra 12mm which wouldn't be enough to batten, but it possibly might be enough to dab it to the wall and secure with a few mechanical fixings...

Are there any disadvantages to going with a "normal" tray? i.e. is using upstands the preferred method these days?

 

[Just Rizzle]

put in a normal tray and get some aqua straps which u stick to the out side of the tray and create a up stand that can be adheared to the tray AquaStrap Aquastrap Shower Seal UK & Ireland | Seal a Shower | Bath Seal

 

[p4ulo]

Wow, never seen "upstands" before, but it seems a great way to eliminate any "leak worries" at the crucial tray to tile edge??
Personally, I would fix the tray as you have it there, then build the walls that are already boarded with a further layer of 6mm Hardiebacker to bring it level with the upstand.
The brick wall....batten out with some thin (8 - 10mm) wood battens, and drill and rawl plug fix through these into the brick. Don't need to use washers, but I would countersink the screw holes so that the screw heads are then level with the Hardiebacker.
Don't use "bash fixings" as the board is fairly brittle and they will go through it.
Tank it all afterwards with a BAL Shower-waterproofing kit and jobs-a-goodun.

 

[Dan]

I was just about to say as Dave said. The extra width you've found out it has, is meant to be there and part of the wall. So moisture always runs into the tray.

It is a 760 tray. The rest is for the wall. So you might be okay dot and dabbing as you wanted to maybe?

 

[Just Rizzle]

if you get some aquastrap tape take the tray out and apply then you could tile down to the upstand lip no need to bed out or dot and dab

 

[Dave]

Just to add to my previous post , if you tile down to the upstanding top and your tile is thicker than the upstanding , then the shower screen will have an unsightly void and how will you get a seal to tile/upstanding , this is the reason you tile down to the tray , to keep it watertight as possible , hope this helps.

My advice is you recess the tray and dry line the other wall , use a tanking paste to offer protection if using plasterboard. If using a cement board , then follow manufacturers guidelines.

 

[Just Rizzle]

just looked at your main photo again
cut in the tray to the backer board so the tray lip is recessed then double board and tank so all lips are resessed the tanking I would use is shulter membrain and over lap it onto the trays lip to form a seal gl

 

[gmt1981]

Thanks for all the advice. I think I will cut a section of the backerboard so that the tray can be suitably recessed. However, is it ok that the back and left side of the tray will be butted-up against the stud work?

I suppose any water that gets through the tiles/grout should just run down the front of the backer board and onto the the upstand, so in theory it shouldn't matter if there is no waterproof/resistant material behind the sides of the tray.

Where the board meets the lip of the upstand, would it be a good idea to put a bead of silicone along the joint, just in case water tries to find its way in between?

Dan - good point on the right hand wall. As you say, if the board needs to be flush with the inner edge of the upstand then I should be able to batten or stick the board without too much trouble.

 

[Dave]

I think you have it sussed .

 

[Dan]

Maybe tank the wall that it only butts up to so it still becomes part of the tray.

 

[gmt1981]

Does that not defeat the point of using water resistant backerboard? If having to tank, I may have well used plasterboard - does it depend on what you are recessing into when determining if tanking is required?

I want to do a proper job but dont want to fork out for tanking kit when it will only be used for a strip of about 2 inches!

 

[Dan]

I was just thinking of that lip. When you tank it becomes part of the shower tray.

That said I've just found a thread that says not to tank it. It affects adhesion.

Have a look at the recent threads. They've just been replied to. Specifically the last couple of posts in the 'hardibacker - any questions?' Thread.

 

[gmt1981]

Thanks again for all the replies.

As you can see from the photograph below, I've cut away a slim section of the backerboard to allow the tray to be recessed into the rear and left sections of the backerboard.

Before i fix the tray in place and attempt to sort the solid wall on the right, does the upstand need to be flush with the outside edge of the backerboard? As it is, the edge of the board overhangs the upstand by ca.3-4mm, which would cause a void behind the tiles.

I can bring the tray out a bit so that it would be flush, but this would require me to build out the studs with a thin piece of wood which is just added hassle.

Also, what is the best way to fix the tray? Getting to the rear and central legs are a no no, and even driving a screw into the front legs looks very tricky.
Many thanks

 

[p4ulo]

It shouldn't matter that its set into the wall further than the board, the tile will be stuck to both surfaces, when you put your adhesive on (either wall or back-buttering) make sure you bring it flush then.
As for fixing, I presume the legs will be solid etc, fairly sure a plumber / installer would smear a tube of silicone over all sides that make contact and push it firmly into place. Once sealant goes off, its deffo in there.
Other option if legs have screw holes - I've got a nifty 90 degree screw-driving attachment for my driver which would be perfect?