I'm about to tile a shower alcove. However, I put a straight edge against the walls and the rear wall bows out very badly. The wall is 950mm wide and putting a straight edge across shows a gap about 8mm at it's max in the centre – i.e. big enough to get my finger through! I'm using 500mm wide tiles (by 250mm high) in a brick pattern. I did have a go at tiling it as is and just putting the tile adhesive on quite thick in the centre of the wall to try and fill out the gap a bit, but it looked awful so I've taken the tiles off.
The wall itself is a plastered external brick wall. The house is 1930s. I live in the UK.
Please could you advise what would be best to fix the issue to give a flat surface to tile on to? I was thinking of getting some ready mix plaster and spreading it on to level the gap – i.e. I'd spread it about 8mm deep in the centre and feather it out to 0mm at the edges, using a straight edge to check as I go. I wouldn't attempt this myself if the plaster would be the finished surface, but I think I can do a decent enough job given it will just be tiled over. Does that sound sensible and if so:
- what type of plaster should I use?
- do I need to prep the wall in any way before plastering? I've already painted on the primer the tile shop sold me that was to prep it in advance of applying the tile adhesive (I think this is just some sort of glorified PVA).
If the gap when split is less than an 1/8" it's probably acceptable to caulk it and then tile around it if you so choose. If the gap is bigger than 1/4" (between an 1/8 and a 1/4 is debatable) you can consider scribing the c-top into place but it will require a diamond grinding wheel and nerves of steel. You may want to consult a professional stone mason on that one. The biggest problem is you're adding scribe to the cabinet and loosing depth and width on your top which is subtracting from your overhang so you'll have to be judicious. Anything less than say a 1/2" of overhang will look odd. It should be noted that this kind of problem would require your wall to be out of square by 1/2" over 30"-36"? depending on your vanity. That's a lot. If that's the case, you might want to consider fixing your walls before you begin setting cabinets. If the problem is just an acute build up of compound in the corner, you may be able to scrape off the mud where needed but if you have to start cutting in to the drywall below the paper, its not worth it. Best of luck!
Best Answer
Just in case this helps anyone, I spoke to the people at the tile shop and they recommended building the wall out using cement based tile adhesive (the type you buy as powder and mix). I did this and it worked well. You have to work fast though, that stuff dries very quickly!