So our ceiling fell down...

[MatthewC]

Thanks for the replies everyone. I think I'll use a hair and lime putty mix to repair the ceiling.

Hi Damon

If you are doing it yourself, I hope you have strong arms! I found it really tiring as you push the first coat of mortar through the laths. NB Make sure that the gaps are clear as that nib is crucial to the strength of the finished ceiling. Also, you don't want to go walking about up above for some weeks until it has dried. The first coat (I used Mike Wye 3:1 haired mortar) is about one cm thick and is scratched to make the base for the subsequent coats - it all hangs on the nibs. The second coat (also 3:1) is without hair and gets a going over with a wooden float to smooth it (hence "float coat") and to make a rougher finish for the third coat (only a few mm) for which I used 2:1 plaster from Mike Wye. My final coat was Regency plaster as I wanted a fine finish, but you could stop after the third coat.

NB I used ready mixed plaster in order to take one variable out of the mix!

As regards dampness generally, it can take literally years for the place to dry out entirely - it's liveable after a few months but the process continues for ages

Matthew

 

[Chris-Burgess]

Repairing a ceiling like this is quite straightforward, your first coat should be haired with a good strong hair like horse or ox hair, looking at the picture your laths look like sawn lath with tend to be more flexible than riven lath. Wet the lath work down with a water spray bottle and keep the edges wet, scratch this first coat with a single sharpened lath in a diagonal pattern, try not to scratch the mortar across the lath interstices as this will cause the mortar to become weak, don't scratch too deep either. I use wood lath scratchers for lath work as I find a steel scratcher can cut the hair again causing weakness in the plaster, let this coat go white dry,Second coat can be haired but with a little less than the first. Wet down the scratch again, Use a straight edge and rule off the existing plaster, when this is ready a wood or poly float should be used in a circular motion to bind the mortar together then should be keyed with a devil float. Cut the edges back with the toe of the trowel to allow for finish coat. Allow to go white dry. Finish with lime putty finish either smooth troweled or float finish.Clean your edges with a sponge hopefully you should have a seem less patch