plastering

[Tim Smith]

Hi

Moved house last year and the new place needed loads of plastering done. Rather than pay a plasterer to do it all, I went on a course.

On the course we were taught using a sand/cement undercoat onto bricks followed by a skim coat. Most of the plaster at home had to come off becuase it was all breaking away anyway, so I redid using sand/cement and then a skim coat.

I recently had a plasterer in to do some ceilings which didnt want to do and he suggested that bonding coat would have been an alternative.

Was it wrong to use sand/cement or is this just a different way of doing it ? Im sure the sand/cement would be very difficult to remove from the walls now !

Tim

[Andrew Gabriel]

Bonding coat is much easier. You would normally only use sand and cement to provide a waterproof undercoat (if you add a waterproofer to the fix). A plasterer is even less likely to use it as he has to wait 24 hours before doing the finish coat which turns a job into at least 2 days -- with bonding coat, you can do the finish coat with 2-3 hours.

You would have learned sand and cement on the course because it doubles up as training for rendering, and because they actually use something called 'student mix' which is sand and lime. It handles like sand and cement, but you can pull it all off after a couple of days so the classroom doesn't keep getting smaller;-) It can be recycled by baking it too, but I don't think anyone bothers with that nowadays. You will find that if you know how to handle the sand and cement, you should have no trouble using bonding coat instead -- it just goes off faster.

[Tim Smith]

Thanks Andrew,

I wont try and remove all the sand/cement that I did then !

Tim

[Rob Morley]

Normally browning for sound unpainted brick or block, bonding for everything else. Cement will be more resistant to damp, but probably not an advantage in most applications.