Hello guys PLEASE HELP

[Dimmy]

HELLO GUYS.

We have put a new timber extension on the house and on the exterior we have used cement render boards (white ones like aqua panel boards)

My plasterer has sbr'd these boards and plastered them with sand and cement......

Needless to say it hasn't adhered to the boards and all fallen off

What can we use/do to put it right?????

Thanks

 

[Dimmy]

 

[Dimmy]

 

[Dimmy]

After and before

 

[stuart23]

Hi dimmy, these boards are not meant to be used with sand and cement as it's heavy. You'll need to strip it all off and get someone in to put something lightweight on it. The guys who know more than me will be along soon @Runswithscissors @Rigsby

 

[flynnyman]

HELLO GUYS.

We have put a new timber extension on the house and on the exterior we have used cement render boards (white ones like aqua panel boards)

My plasterer has sbr'd these boards and plastered them with sand and cement......

Needless to say it hasn't adhered to the boards and all fallen off

What can we use/do to put it right?????

Thanks

Another plasterer?

 

[Olican]

What was he thinking [emoji15]

 

[malc]

it is a no no to apply sbr to cement boards. you could well have lost the key for the thin coat render. i would overboard the extension with knauf cement board and employ someone you knows how to apply a thin coat system.

 

[Rigsby]

As Malc above has said. You will need a spec of a manufacturer such as Weber, Parex, K Rend, SAS Europe, SPS Envirowall.

Weber is in Flintwick, Beds there technical will advise.

 

[Runswithscissors]

Hello mate

Comments above are all correct.....

You do not want to prime or SBR boards prior to rendering, you want the render to fully bond to the board

You need a modern thin coat basecoat and mesh application to the boards first, this binds all the boards together using a flexible base to restrict cracking, it is then best to use a think coat finish coat onto a timber frame, 2 reasons:
S&C is heavy and will cause extra shrinkage in the TF frame
S&C is brittle and will crack as the timber frame settles (all timber frames settle anyway)

Pick a system supplier and get a spec for the boards and render, then get a Renderer who has done this before (as to see previous work, visit if you can)

Sorry, probably not what you wanted to hear....

Good luck
Richard