Limewash as a primer?

[inwood]

I used some limewash to stabilise a dusty wall the other day before plastering a skim coat over the top. I noticed that there was significantly less suction from the wall after doing this to the extent that I was only able to trowel the plaster off the next morning. The set seems much slower and the finish much better.

Has anyone else experienced this slowing of suction when using limewash before the final coat? Since there are so many variables involved I can't tell whether it was a different background/humidity/time of day/temperature/colour of shirt I was wearing.

 

[Gervase]

Aye, I often use dilute limewash as a tack coat, particularly on walls with a mix of impermeable stone and mud/lime mortar. It can also help if you need to skim over an overly-trowelled finish coat and it hasn't got much of a key. If I'm mixing plaster using tubs of putty I tend to sluice out the tubs with a bit of water and and a churn brush and save it for wetting down the walls, or if the sand is damp I'll pour off the surface liquor and dilute it down a bit and use that - the wash can be pretty weak but still give significant advantages.

 

[Mark]

Yep. I've also used it as a primer on a patch of plasterboard. I had to replace a bit under the stairs and tried it to see what would happen - expecting it to fall off because I kept reading that I needed a special primer - now I just have untidy lime plaster. One day I'm going to have to skim it so it doesnt look such a mess.