PVA or not

[Webskater]

I need to render a fireplace which is going to have a log burner in it. The fireplace is formed with a mixture of concrete blocks and bricks.

Above the fireplace is a concrete throat. I have to render the fireplace itself and an area about 9" wide to the left, right and above the fireplace opening. The areas on the left and right are concrete block - the area above is the front of the concrete throat unit.

How do I get a sand/cement render to stick to the concrete throat unit - and, for that matter, to the concrete blocks/bricks?

Do i unibond first - and let it dry? And use unibond in the scratch coat?

Any advice much appreciated.

 

[johniosaif]

I would use an sbr scud over it all the day before.

 

[beader]

Don't use pva the heat from the fire will make it re emulsify.

 

[carlos]

SBR all the way its 100 time better than PVA.

 

[johniosaif]

Don't use pva the heat from the fire will make it re emulsify.

Sounds like a dance move,

 

[barryed]

Are you a spread?

 

[S a plastering]

hit it while its tacky sbr doesent work aswell when its dry it polymerises

 

[Arti]

Are you a spread?

is that question to asif.......................:RpS_laugh:

 

[johniosaif]

is that question to asif.......................:RpS_laugh:

Ask myself everyday...

 

[Webskater]

No - I'm a diy er quite happy to pay a plasterer - but I can't find anyone local bothered to do the job or confident they can do the job.

 

[Webskater]

Folks - thanks for all the replies. What is SBR?

I understand you have to apply a slurry and I have read 1 part sand to I part cement to I part 'SBR'. What is SBR?

 

[Webskater]

Okay, would have edited last post but cannot. I have found out what SBR is .. an additive from Cementone.

So, how to apply the Scud coat?

I part sand to 1 part cement to 1 part SBR? No water. Just pure SBR?

Wet the wall first ... let the excess dry out and apply it while the wall is damp?

How thick to apply it? Can I apply it with, say, something like a 6" paintbrush that you might use for masonry and slap it on / dab it on?

Does it have to then have a scratch coat on it the next day?

Should the scratch coat have SBR in it?

What's best to finish over the render with? The fireplace itself will just be render but the area outside, to the top, left and right will be visible and painted. Years ago we used Sirapite over render, but I guess that is no longer around. I'm told you shouldn't use a gypsum based plaster around a fireplace ... so how to get a paintable finish on the render?

 

[Gazza1987]

Theres a new product called rendagrip ideal for situations like this

 

[Rigsby]

Theres a new product called rendagrip ideal for situations like this

Or Sovereigns PlastprimeX.

Order direct from Sovereign