Rendering a wall

[Terry-La-Tiler]

I take it you mean the finish came off leaving sand and cement backing, Is it old and soft or quite strong, If tapped does it sound hollow or firm...?

First of all, thanks guys! The replies have been extremely informative and the level of response really encouraging.
Whitebeam, you ask if the render appears hard, soft or hollow. Well it feels hard but when tapped sounds hollow in places. I really am a novice at this game and didn't want to start removing render and adding new plasterboard. If that's my only option, then so be it.

Oh, and a spirit level does indicate that the wall are at least square. Suppose that's one consolation.

I like the sound of this quickset render by BAL. do you suppose I might get away with using this stuff? Even if I have to spread thinly over the whole area, admittedly with additional cost, it seems like the easiest and quickest fix.

I would add an image but not sure yet how to do that.

Anyway, thanks again guys.
Terry.

 

[White Room]

I would remove the hollow areas and patch, No major work involved

 

[doug boardley]

terry, been thinking of your quandry during course of day, when you said all the plaster had come off with the tiles its crossed my mind that maybe you meant the skim coat, was this about 2-3mm thick? In my neck of the woods we don't refer to it as plaster just skim, if it is this coat that has come off with the tiles please accept my apologies for going overboard, as it would be ok to patch the tennis ball size area,sbr and tile onto sand and cement.
good luck,
doug

 

[Terry-La-Tiler]

Hi Doug,

Yes, that's exactly what I meant. Almost all of the pinkish skim has come of with the tiles and I am left with a sandy cement like finish, a few area's of this surface then also contain holes the size of tennis balls. It's a very rough surface but having put a spirit level to it have found it at least to be square.
Can I remove the remainder of ths pinkish coloured skim and apply a thin coating of the BAL render that was mentioned earlier?

To be honest, this whole first project is feeling like a bit of a nightmare right now but I'll definately get there in the end.

Thanks again for your help mate.

Terry.

 

[doug boardley]

yeah Terry, scrape off the skim, fill in the holes with the bal stuff, wouldn't be concerned about the sand and cement being rough texture (as long as its flat with no humps and dips) scrape off loose dust etc with back of plastering trowel, sbr, and then you should be good to go! incidentally sand/cement render is my favourite substrate to tile onto. Don't let it get to you I'm sure you'll get there in the end!
good luck
doug

 

[DHTiling]

yeah Terry, scrape off the skim, fill in the holes with the bal stuff, wouldn't be concerned about the sand and cement being rough texture (as long as its flat with no humps and dips) scrape off loose dust etc with back of plastering trowel, sbr, and then you should be good to go! incidentally sand/cement render is my favourite substrate to tile onto. Don't let it get to you I'm sure you'll get there in the end!
good luck
doug

So.. if you have a sand cement base coat and you then apply a skim coat...(gypsum i presume)..this is ok is it...

 

[White Room]

If you can try and scrape the rest of the finish off but don't worry if it won't come off, Leave it. Remove all the loose areas of render and fill. I would prime walls with Bal apd or sbr (sbr thinned down to 3-1). I would use powdered adhesive, You don't mention what tiles you are fixing

 

[doug boardley]

sand and cement preferably with hydrated lime is the perfect base coat to skim onto Dave, ok its thermal insulation properties are not as good as insulated plasterboards, and if tiling onto I prefer no skim on sand and cement especially with large format/ high density tiles

 

[Corky]

So.. if you have a sand cement base coat and you then apply a skim coat...(gypsum i presume)..this is ok is it...

yes Dave sand and cement is a perfect base coat for a skim finish.If the s/c is fresh no bother at all to skim over as the plasterer usually key it with a devil float or if an older basecoat check the wall is sound (no hollow sound when tapped with hammer ) if not and the wall is blown repair or remove.If base coat is solid kill the suction with pva @5 or 6/1 the day before and give it another run of same before skimming while pva is still tacky.

 

[DHTiling]

So..pva will stop ettringnite reaction/failure between the cement base coat and the gypsum skim/top coat..?...