Can you plaster onto breeze blocks? and ventilation help!

[puddleduck36]

Hi all,

I'm taking some horrendous boarding off my hallway walls, and have discovered that there's just breeze blocks behind them, with a rather draughty gap between the board and the blocks.

My questions are:

Can you plaster straight onto breeze blocks? I'm not too keen on plasterboards as this would feel like doing things twice, but will do if it's strictly necessary?

and

Would there be any reason why there's a draught between the tw- i.e. are there any ventilation regulations I need to be aware of that plastering straight over the breeze blocks would contravene?

Any advice gratefully received!

 

[roughcaster]

I think the gap would have been a natural gap between the breeze blocks and the "horrendous boarding" you have removed. Was the boarding attached to battens?
Anyway, you can plaster directly onto breeze blocks. You'll need to float and set, (undercoat/top coat plaster). Use either Hardwall, Browning or sand and cement render for the backing/undercoat,, then finish with Multi Finish.. If you go down the Hardwall/Browning route, you can finish the same day, but if you go down the sand and cement render route, you will need to leave the finishing for a day or two. Either way, give the blocks a soak before you coat them.

 

[puddleduck36]

That's great info, thanks very much

When you say 'a good soaking' - what do you mean with? I know you need to PVA (or equivalent) the surface, but is this what you mean or am I missing something essential?

Thanks again

 

[roughcaster]

When i said soak the blocks, i really meant, give them a wet down with a brush, spray or similar,,, brush/flick the water on. It's always better to apply plaster onto a wet/damp surface rather than a dry one, especially a surface with suction. As you mentioned, diluted PVA can also be brushed onto an absorbent surface to cut down the suction.

 

[puddleduck36]

Ah gotcha That's been really helpful, thanks so much!

 

[roughcaster]

Will you be attempting the plastering yourself, or will you be getting someone in to do it?

 

[puddleduck36]

I've done plastering before with good results, but I wasn't the one buying the materials at the time so I'm just refreshing my memory and checking the jargon, so to speak.