External water feature queries

[Brad]

Morning all

Start a new job on mon. Tiling an outside water feature. Just have a few questions. Builder tells me the bricked wall was rendered about two weeks ago and is approx 12mm thick on average. Same applies to the horizontal/base bit. From what i have been taught i need to leave at least four weeks for the render to dry before tiling. Have told the builder this but he assures me the render is bone dry due to good weather and wants me to go ahead. Going with the builder on mon morning to buy materials. The brand will more than likely be Mapei. Any suggestions on adhesive type? Have been told to be careful when choosing adhesive so as to prevent watermarks from seeping through to the front of the tile. Also, what about sealing the render? Should i use P51? Does Mapei have an equivalent?

Tiles are 600x600x12mm. They are black granite. Have been told that they need to be sealed. Any suggestions here?

Lastly, there is a bit of external floor tiling to do next to the water feature. A slab has been laid and a 50mm screed was put down two days ago. Builder says that the he is having to hose the screed down as it is drying too quickly with the good weather. My instincts tell me not to rush this one. Any advice?

Thanks in advance for your input!

[365drills]

Not advice but just a tip that if you need to cut holes in the granite for service pipes then dont forget us!





Perfect holes in granite block (this sample = 20mm thick)

[grumpygrouter]

Morning all

Start a new job on mon. Tiling an outside water feature. Just have a few questions. Builder tells me the bricked wall was rendered about two weeks ago and is approx 12mm thick on average. Same applies to the horizontal/base bit. From what i have been taught i need to leave at least four weeks for the render to dry before tiling. Have told the builder this but he assures me the render is bone dry due to good weather and wants me to go ahead. Going with the builder on mon morning to buy materials. The brand will more than likely be Mapei. Any suggestions on adhesive type? Have been told to be careful when choosing adhesive so as to prevent watermarks from seeping through to the front of the tile. Also, what about sealing the render? Should i use P51? Does Mapei have an equivalent?

Tiles are 600x600x12mm. They are black granite. Have been told that they need to be sealed. Any suggestions here?

Lastly, there is a bit of external floor tiling to do next to the water feature. A slab has been laid and a 50mm screed was put down two days ago. Builder says that the he is having to hose the screed down as it is drying too quickly with the good weather. My instincts tell me not to rush this one. Any advice?

Thanks in advance for your input!

It is normal to allow 1 day per mm of render thickness for drying time, therefore your 12mm render should be fine. The 50mm one won't though. Render doesn't need to be primed before tiling (though check with the actual adhesive manufacturers instructions first) and you won't get any bleed of adhesive through black granite! I can't comment on Mapei adhesives as I haven't used them yet but BAL rapidset or flexy would be fine, or if you want something that gives you more time try Goldstar or SPF if you want to use flexy stuff.

If the tiles are polished, then it can be a good idea to seal with an impregnating sealer just to fill the open pores from the polishing, but granite is very dense and won't absorb much if any moisture or the like. I use Lithofin Stainstop MN for granite.

Good luck, let us know how you get on and don't forget to post some pics.

[DEtileD]

Couldn't have said it better myself Grumpy.
D

[grumpygrouter]

I forgot to mention in my previous post. If you need to tile the 50mm screed fairly soon, have a look at BAL Green Screed adhesive. This is designed for fast track tiling in situations like yours. Quite expensive stuff though, I believe.

[DEtileD]

I forgot to mention in my previous post. If you need to tile the 50mm screed fairly soon, have a look at BAL Green Screed adhesive. This is designed for fast track tiling in situations like yours. Quite expensive stuff though, I believe.

Probably looking at around £23 +Vat per 15kg bag in most shops (with your Discount that is).
D

[MICK the Tiler]

As grumpy has said the 12mm screed will be fine but the thicker screed will need more time as for the extra cost of a green screed addy then at 23 quid for a bag that would be good value if your pushed for time.

If you have not laid the screed yourself make sure you tap it with a hammer to make sure there are no "Drummy" spots as these will need to be removed and repaired before tiling work starts.

A quick test for dryness of the screed is to lay a tile down on the screed and leave it overnight and when you lift it in the morning if there is a moist spot the screed is still too wet if there is little or no moisture then it is dry enough to commence fixing.

Personally I'd seal the granite with an impregnator sealer especially in the water feature as this will help reduce any water line scum in the future.

[whitebeam]

You don't want sand and cement drying out to quick either

[Brad]

It is normal to allow 1 day per mm of render thickness for drying time, therefore your 12mm render should be fine. The 50mm one won't though. Render doesn't need to be primed before tiling (though check with the actual adhesive manufacturers instructions first) and you won't get any bleed of adhesive through black granite! I can't comment on Mapei adhesives as I haven't used them yet but BAL rapidset or flexy would be fine, or if you want something that gives you more time try Goldstar or SPF if you want to use flexy stuff.

If the tiles are polished, then it can be a good idea to seal with an impregnating sealer just to fill the open pores from the polishing, but granite is very dense and won't absorb much if any moisture or the like. I use Lithofin Stainstop MN for granite.

Good luck, let us know how you get on and don't forget to post some pics.

Thanks for the advice grumpy. Just one thing, you say there is no danger of adhesive bleeding thru black granite. Does that mean I don't need to worry about water bleeding thru. Was told by a mate that if i don't use the right adhesive i will run the risk of water bleeding thru and causing water marks on the front of the tile.

Also, when sealing the tiles prior to installation, should i seal the back or just front face and sides?

[Brad]

Thanks for that Mick. Will keep your advice in mind.

[Brad]

Hi Grumpy.

One further question. You say that render doesn't necessarily need to be primed. Are you saying that cement needs to be but plaster doesn't?

I'm still very green. Thanks for tolerating us newies!!

[devonmark]

Hi Grumpy.

One further question. You say that render doesn't necessarily need to be primed. Are you saying that cement needs to be but plaster doesn't?

I'm still very green. Thanks for tolerating us newies!!

plaster does need to be primed, s&c render doesn't..Mark