Levelling a wall - any help please! [pics]

[Kasheen]

Hello folks,

I'm wondering if anyone can point me in the right direction with levelling a wall that I'm about to tile.

I've completed the first wall which was fine, nice and level for the most part (or nothing that building up a small bit of adhesive wouldn't solve). However when I placed my wooden batten across my second wall I noticed that it bows into the middle.

It appears that most of the problem is from the very sides (left and right) of the wall where it slopes up quite sharply, while the middle might be a bit more flat with the odd lump or bump.

Here is the wall:


With the batten placed across the entire wall it is raised off of the wall:


With my spirit level placed in the middle of the wall the gap is much reduced so I think the sides are causing the batten to raise (1cm would be an extreme max for the gap, I think it's around 0.5):


A single tile produces hardly any gap:


So I'm not sure how I should go about solving this? Is it actually an issue, i.e. should I just be raising and lowering the tiles with adhesive so they match up but still have the wall overall bowed?

Or should I attempt to plaster the wall to level it off (my plan was to flatten the plaster up using my batten to make it level, it's behind tiles so I imagine it doesn't have to be too neat). Could someone help me with the method for doing this? (I'm plastering ONTO finishing plaster (urg) so how would I key it, what plaster should I use to build up the 2cm gap in the middle etc). I don't think I could use plasterboard because it would make the tiles jut out from the wall quite alot. Obviously I'm mostly concerned about the weight of the tiles pulling the new layer of plaster off of the wall.

Much appreciated for any advice, thanks will be added (and possibly pics of progress ).

[Scott]

You could skim it with adhesive, depending on the type of adhesive you are using. If its a cement based adhesive you can skim over the dipped areas and/or use a deeper notched trowel to over come the dips.

Or you could plaster it. Wouldnt be too hard either way as you are filling in dips as opposed to removing a high spot

[Ceramico tiling]

I would plaster it in the middle with rapidsett but no thicker than 12mm,(use a batton as a fether edge)then when its dry level as I go with the tiles if it still needs it,,But there might be better ways(materials)etc which these guys might know.

[Kasheen]

Thanks so far guys!

Ok so options seem to be skimming with adhesive (I'm currently using a 2 in 1 grout and adhesive tub by Unibond, I've been reading these forums and I'm guessing that this prolly isn't suitable to skim a wall and I'd need to buy some kind of bagged product) or skimming just a bit with rapidset plaster and then working the rest out with my tiles and adhesive as I go.

Is there any way that I should prepare the current finishing plaster for the extra skim? Should I sand it, or scratch lines into it with a stanley knife to make a key? Perhaps if I'm taking the plaster route then using PVA to seal the wall? (I know this is a hot topic for tiling, I've personally not used it with my tiling adhesive).

[GirlRacerRed]

If you're putting tiles on top of it, DON'T USE PVA

[Diamond Pool Finishers]

yes skim with addy ,and use your wood as a rule to take off excess

[mikethetile]

plasterers use pva to seal the wall before skimming over existing plaster

its probably your best bet but you will need to allow to dry out for a few days before priming and tiling

[Phil Hobson]

I would bin the Unibond, and use a good cement based adhesive. Prime with SBR, and follow the above advice. Good luck

[Phil Hobson]

Sorry about my print, I must have clicked italics by mistake

[tiling spread]

use pads of plasterboard cut say 4ins square dab them on with tile addy top and bottom say 14ins apart se a lond level too plum it up let the pads set then pva the wall then lay on some bonding rule off livel with the pads trowel it in let it pall in then devil float dry then tile sorted same as F&S gatting the wall plum

[whitebeam]

It's not recommended to tile directly onto thistle bonding

[Scott]

use pads of plasterboard cut say 4ins square dab them on with tile addy top and bottom say 14ins apart se a lond level too plum it up let the pads set then pva the wall then lay on some bonding rule off livel with the pads trowel it in let it pall in then devil float dry then tile sorted same as F&S gatting the wall plum

As previously mentioned bonding is not suitable to tile on

Read page 4 of the data sheet
http://www.british-gypsum.com/PDF/DS...ing%20Coat.pdf

[Scott]

Beat me to it Whitebeam

[Fred]

Get a good plasterer in and sort it out.

[Phil Hobson]

It's not recommended to tile directly onto thistle bonding

Not enough strength in it Btw. thanks for sorting my print Dave, Dan, Mods? whoever did it. Very impressive

[tiling spread]

then two coat skim it then next you cant tile on too finish

[whitebeam]

If you pva the wall it will only take about 20 kg

[Kasheen]

Wow!

Can't believe the amount of replies. Ok so it seems most are suggesting just to build up a skim layer of tile adhesive. I see that alot of people rate BAL products, can anyone suggest one of their bagged products that is easy to use and has decent mileage (covering 1.5msq with addy is more expensive than using plaster). Russ has suggested rapidset, will this go off too quickly for a beginner taking their time?

Also is there anywhere that sells BAL on the cheap, Topps seem to want £26.99 (not bad considering the unibond cost the same) for grey and £36 for white (can I go with grey even though I'm going to use white grout?). The flexible stuff costs even more at £45.99 (do I need this, the wall is going to be around a rolltop bath, shouldn't be too wet since it's not a built in bath).

So any help on which adhesive would be great, then hopefully I'm onwards to success

[macten]

yes skim with addy ,and use your wood as a rule to take off excess

Fnarr Fnarr!!

[macten]

Use rapid set and mix it quite thick, if you're anything like me I get impatient and try to put too much on and it can slump.
Try to source the cheapest rapid set (usually grey) when skimming walls or it could cost you a small fortune. BAL is good but BAL is dear.

[Kasheen]

Use rapid set and mix it quite thick, if you're anything like me I get impatient and try to put too much on and it can slump.
Try to source the cheapest rapid set (usually grey) when skimming walls or it could cost you a small fortune. BAL is good but BAL is dear.

Can I also use the grey to apply the tiles, should I buy the biggest bag possible? I've also got a further 3msq of tiling to go after this small 1.5msq section of wall, so I think I may have to buy a big bag and a smaller bag but I'll just buy as I go I guess.

[macten]

You can use grey but you will have to work very clean, particularly with the grout joints.

[Kasheen]

You can use grey but you will have to work very clean, particularly with the grout joints.

Yeah it was the grout joints that I'm worried about. With the white unibond stuff I'm using any of it that is coming out I'm not so bothered because I know the grout is going to be white so it'll definitely just merge in.

I may buy a small bag of grey to skim and a big bag of white to finish the rest of the walls in that case.

[Bolter]

Yeah it was the grout joints that I'm worried about. With the white unibond stuff I'm using any of it that is coming out I'm not so bothered because I know the grout is going to be white so it'll definitely just merge in.

I may buy a small bag of grey to skim and a big bag of white to finish the rest of the walls in that case.

The Unibond can merge with the bin!

Also dont try to "pack out" with ready mixed stuff. In fact, if you are "packing out", your wall/floor is not flat enough.

[cuttintiles]

Dont use timber as a guide, use a straight edge or level!!!

i must admit i am surprised that as your dip is 10mm or less no one has suggested that you use a floor trowel (20x10mm round notch) and serrate the wall and the tile,
if you do this once your first course is on the wall you can use a long level and push the tiles flat!

therefore no need to "plaster" the wall with adhesive!

both ways will work but, as your dip is 10mm and less, i would use a good quality flexi and follow my tip!

[Ceramico tiling]

I suppose a feather edge would be ideal although a straight timber is better than getting adhesive all over my level.When I find there is a gap(filled with adhesive)btw tiles and wall(around 10mm) they all move differently as the adhesive dries which leaves you with lippage that drives me mad personally.So i find it better to maintain a minimal consistent gap by plastering the dips first and allowing them to dry.

[cuttintiles]

i know what you mean about getting adhesive on the level,
but as for shrinkage not true, keraflex maxi provided mixed correctly will handle 15mm (according to mapei's little black book) not to mention i have done it personally, so not just quoting stats!

[Ceramico tiling]

Well kerraquick maxi is one I will definatelly pay more attention to because that would be cool.But I am certain the more the gap of adhesive behind the tiles the more they move by themselves as they dry with most other adhesives anyway.And i doubt this guy is using kerraquick maxi!.I would be interested in some other opinions on adhesive shrinkage?.,

[Bolter]

Well kerraquick maxi is one I will definatelly pay more attention to because that would be cool.But I am certain the more the gap of adhesive behind the tiles the more they move by themselves as they dry with most other adhesives anyway.And i doubt this guy is using kerraquick maxi!.I would be interested in some other opinions on adhesive shrinkage?.,

if using tubbed ready mix stuff yes there is shrinkage. But you should NOT be packing out with that.

I dont know any powdered adhesives that shrink badly.

[Scott]

Dont use timber as a guide, use a straight edge or level!!!

i must admit i am surprised that as your dip is 10mm or less no one has suggested that you use a floor trowel (20x10mm round notch) and serrate the wall and the tile,
if you do this once your first course is on the wall you can use a long level and push the tiles flat!

therefore no need to "plaster" the wall with adhesive!

both ways will work but, as your dip is 10mm and less, i would use a good quality flexi and follow my tip!

A deeper notch trowel was suggested in the first reply