Bonding Compound on Sandtex?

[JonFox]

Hi.. I want to Dot and Dab over an old external now internal wall thats covered in pebble dash painted with Sandtex Paint. British Gypsum technical department cannot confirm this would not fail. Sandtex say there paint is water resistant but designed to take layers etc. Appreciate battens is probably the ideal but any thoughts?

 

[Builderboi]

Put mechanical fixings and a pregrit

 

[zombie]

Personally I'd just dabb it...however I think batton is probably the correct answer.

 

[duke163]

Pre-grit and dab it

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[raggles]

As zombie says and if paranoia crept in I'd put a couple extra mech fixings per board.

 

[flynnyman]

Put a tight coat of dab adhesive onto where your gonna put your dabs first.

 

[essexandy]

Hi.. I want to Dot and Dab over an old external now internal wall thats covered in pebble dash painted with Sandtex Paint. British Gypsum technical department cannot confirm this would not fail. Sandtex say there paint is water resistant but designed to take layers etc. Appreciate battens is probably the ideal but any thoughts?

Why not stick a small piece of board straight onto the wall and once fully set do a pull test?
No one can really say what is suitable without at the very least being there to physically check the wall.