Floor prep

[Mouldy]

Hi fella's
Looked at a job today, around 25m2 of floor tiling, 400mm square 12mm thick polished granite tiles. The floor as it stands is carp in the extreme, some butcher has been in with a couple of bags of latex and spread it aroundarbitrarily.

I ran an 1800mm level around and there are two or three low spots of around 12-15mm and one high spot of around 20mm in different areas of the floor.

Is it just a case of latexing as required or would it be better to grind out the high spot as best as possible first and then level? Fixing the tiles isnt an issue but I know the main part of the job is in the prep and havent come across a floor as bad as this before!

 

[mz30]

If it was me i would make them sort it until your happy,i try not too get involved on really bad floors,small problems can be got over but big ones i tend to swerve.

 

[Mouldy]

Already said they could have a go at sorting it but they were not interested. If I dont do it then Ill lose the job and I'm not in a position to turn it away at the moment!! Its all gone a bit quiet.....

 

[Gazzer]

I would be wondering how secure this levelling was. Doesnt sound as if they know what they were doing. So have they used the correct stuff?

 

[mz30]

Is the 20mm high spot over the floor level so that the low point is 35mm lower than the the flat part of the floor?

 

[Martyn Leeds]

What's under the latex?
ply, concrete, 6mm hardboard?
priming and all that?

Sounds like you're gonna have to sort the levels out.
So if it were me, I'd be finding everything out and then deciding and quoting for the best solution, I think.

 

[Mouldy]

Sorry, OP should have said that its a solid concrete floor. Latex thats been put down was a two part powder/polymer liquid type.

Highs and lows were much further apart then the 1800mm straight edge I had to hand so didn't get direct difference's.

 

[mz30]

Can you get the floor flat mate? Thats what i would be asking my self,not all floors are going to be great, its a catch 22 you need the work but you want to do the job right,if you need the work chop out the high point and screed the low points not ideal but sometimes needs must.

 

[Mouldy]

Looking into hiring a floor grinder to take out the high spots. Will then fill the hollows with SLC and then give the whole floor a going over with SLC. I suspect the price will put the customer off but the room is about six meter's in length with a French door at one end, so a point light source right to the floor. If the tiles they have chosen are not flat then it will scream!!

 

[charlie1]

If the high spots where just localised areas then I'd certainly consider grinding down. A the end of the day mouldy, if you feel you have the expertise to do this job then go for it, sometimes we need to push the boundaries though, you live and learn! Go for it man, if you don't then someone else will!

 

[Mouldy]

Loving the attitude fella, Go get 'em Tiger!!!

Have no issues with doing the job, its just that Ive never tiled a floor that's this bad. Ive tiled loads of floors but all in bathrooms and generally suspended, occasionally I have tiled concrete floors in bathrooms of bungalow's. However as stated non have been of this area and non as bad.

Obviously I know that the finished surface is only as good as whats below it, so the substrate has to be decent to start with.

Its around 25m2. I need to take out the two high spots and fill the low spots, then probably give the whole floor a couple of coats of SLC to get it to a decent state. I estimate around a day grinding and filling, then more time for the further coats of SLC. Probably around 6-8 bags of the stuff.

As a guide what sort of price would others be looking at for this? Ball park is good enough!!

 

[Mouldy]

OK, need to re address this as I won the job!

Have carved up the existing SLC as in places it hadnt adhered and mostly it was in the wrong places. Had also found out that the guy who laid it had added water into the mix. Idiot. Ran a grinder over the high spots.

Having got the floor back to the original slab I SBR'd it all and wound in six bags of Weber SLC, (damned good stuff it is too, can bucket it in up to 50mm!) Three and a half bags went in yesterday and the rest went in to day just to float over and get a nice surface.

Now this room was in fact three rooms at one point, so there are three floor slabs. Because of this Ive decided to fix a de-coupling membrane. So to the question. Can I fix this tomorrow? Or will the SLC need to be completely cured? I've never fitted this stuff before but have done a fair bit of research. Will use a 6mm trowel with standard set SPF addy, unless I'm advised not to..... Would it be best to let this dry before tiling or can I start tiling straight away?

Anything else I should know?

 

[Mouldy]

Decided not to fix today. Will fix Durabase tomorrow. Can I tile straight away or is it best to let the adhesive dry first?

 

[Peter]

Lay the decoupler with quite wet rapidset and a 3-4mm trowel and bed in with a bit of 4x2, then it will be ready for tiling next day.

 

[Mouldy]

Thanks Pete