Mixing grout with SBR

[Unregistered]

Hi

I have a flat roof to tile with slate tiles and I'd like to make a grout to be waterproof. I've never used epoxy grout and don't want to (not sure if you can use it on slate anyway). I was thinking to mix grout with SBR - what are your thoughts?

 

[widler]

Don't think it would harm it, but when you have sealed the stone and grout it will be waterproof anyway .

 

[Dave]

SBR won't make it waterproof..

 

[Unregistered]

I have sealed the slate on previous work and it proofed to be watertight for a year or so. Let me explain the situation I'm in.
Few years ago this terrace was tiled with asbestos tiles sicked on layer of bitumen. Under the bitumen was few layers of felt and concrete deck. All of this was stripped down to bare concrete and new deck installed. New deck was covered with GRP - some fibreglass and resin. Slate tiles went on top. Now we've found out that there is a problem with GRP deck as it's leaking. Now I thought of two options:
1. find watertight grout and re-grout the whole terrace
2. lift the tiles, put another layer of 6mm plywood directly on existing deck and apply Mapelastic Aquadefense Liquid Rubber Waterproofer then re-tile.

Option 2 seems to be the best way but a bit pricey too.
Do you have any suggestions?

 

[Tile seller]

I wouldn't try chemical mixes unless specified ok by the manufactures. You can seal grout but I cant see it lasting as a long term solution.
Epoxy's good but not cheap and any movement in the tiles means gaps and waters through again.

Option two seems the only way sadly. I cant offer any advice on how best to complete this option though as I'm no roofer.

 

[Unregistered]

I thought epoxy would be flexible so it would allow for a slight movement but as I said, never used it before so not 100% sure. Have you tried epoxy on slate? Does it leave a glaze on tiles? The terrace is approx 40m2.

 

[Lithofin BOB]

Grout protectors or impregnator across the stone or grout , as TS said will not protect for to long, breathable, water may still poss bleed as maintenance products not tanking, ardex do a hybrid epoxy which we tested on very anti slip tiles came of a treat, not sure for naturals, this would give you chem and water resistance but un sure on application on slate , could you do a test board with spare slates to test for release and finish.Would ring them also to discuss suitabilty with slate and movement . Perhaps the guys could comment on here on hybrid product. Can't recall name

 

[Stef]

Unless this is stripped back & done right then it will leak.
I wouldn't even dream of fitting 6mm ply then tiling on top of aquadefence.
Glue & screw an appropriate board suitable for outdoor use then aquadefence it.

 

[Unregistered]

I have some spare slate tiles. I think you're talking about Ardex EG8. I'll try to get some info from manufacturer and I can test it on spare tiles.

 

[White Room]

Don't mix sbr with your grout because it will be a nightmare to clean off, I tried it just the once never again...that'll teach me to try and be clever.

 

[DP Tiling]

A cement based backer board and a proper tanking agent is the only answer here, the mapeilastic aqua defense is great stuff, be sure to use the mapeband around the internals too.

Slate will need to sealed with an impregnator regardless, however, due to acidity/alkalinity of rain water it needs quite a bit of maintenance in that it wears a lot quicker.

Regarding the adhesive and grout, I personally would go for Keraquick and latex plus it is very well suited to external use and it's low water content and rapid hydration makes it ideal for porous stone also it is the same manufacturer as the tanking agent and eliminates risk of chemical incompatibility. Probably wouldn't go to an epoxy grout as I can see it being difficult to fully remove haze from slates textured surface.

 

[nybor62]

EG8, is a great grout easy to use imo

 

[Unregistered]

Don't mix sbr with your grout because it will be a nightmare to clean off, I tried it just the once never again...that'll teach me to try and be clever.

Thanks for that advise.

DP - I know that tanking would be ideal but now when I compare the costs of re-grouting (2 tubs of Ardex EG8 - approx £70 + good grout cutter for multi tool £40) and 2 days of work vs tanking and re-tiling will cost me approx £500 that's if I don't brake any tiles + I estimate 7-8 days of work. Re-grouting may be worth trying but only if there is a good chance of success.

 

[DP Tiling]

I hear you, but it might be a false economy.
Water damage is a costly problem.

That said, we do not live in an ideal world and sometimes needs must.

 

[WetSaw]

How big is the roof? EPDM membrane an option?

 

[Unregistered]

How big is the roof? EPDM membrane an option?

EPDM is not an option. It's a terrace that is being used as a little garden in summer. I know EPDM is a good solution but in my opinion for roofs that are not being used.

 

[widler]

SBR won't make it waterproof..

SBR is used a s a water proofer in external render and internal DPM dave.
But your right, it won't make it waterproof.
Now the whole story has come out, RIP it up, re do it, waterproof the substrate and re tile, regrouting is not gonna waterproof it .

 

[Tile seller]

I had a sample of Mapei mape elastic through today and thought of this post.

 

[Dave]

SBR is used a s a water proofer in external render and internal DPM dave.
But your right, it won't make it waterproof.
Now the whole story has come out, RIP it up, re do it, waterproof the substrate and re tile, regrouting is not gonna waterproof it .

more of a water repeller than proofer. ..

 

[Diamond Pool Finishers]

i would say it depends on the ratio of sbr in the render as to the percentage of waterproofing !

 

[Stef]

i would say it depends on the ratio of sbr in the render as to the percentage of waterproofing !

To me though Dave, it would only be a quick fix & it will eventually fail.
You know as well as I do that water that will find it's way in through any little hole.
Do it right the 1st time & problem is solved.

 

[Diamond Pool Finishers]

Certainly stef ! sorry i was thinking about making a waterproof render with SBR :lol: and not really thinking about the question originally asked ..........

 

[Stef]

Certainly stef ! sorry i was thinking about making a waterproof render with SBR :lol: and not really thinking about the question originally asked ..........

No worries Dave, you know better than me on this subject.

 

[Old Mod]

 

[Concrete guy]

EPDM is not an option. It's a terrace that is being used as a little garden in summer. I know EPDM is a good solution but in my opinion for roofs that are not being used.

Couldn't an EPDM be fitted as a tanking system and then a surface finish applied?

It would guarantee a leak free roof.

We got a kit from these people for our garden office http://www.rubber4roofs.co.uk/

All it is is a tanking membrane, just substantially thicker than a regular tiling tanking system.