Monday, July 26, 2010

Questions about Lime plastering

I'd love to help those of you who find yourselves here looking for some basic information about lime plastering. First of all I'd advise that a course where you actually see and feel the material is much better. A good supplier is a must. They can often help with advice and run courses too. Material on line can be confusing as I've found each country has different names for things, particularly in referring to which layer. I stick to first and second coat, but you may of course apply more. The first coat usually has plenty of coarse sand, or other material such as hair or hemp, to stop the (top) second layer from cracking, and to even out the wall a little. It is applied to a damp- wetted down wall. You could use a ready mixed "coarse stuff" for this. See other entries for information about Hydraulic lime or lime putty. The drying time is slowed down by misting or creating a humid atmosphere close to the wall by hanging dampened hessian cloth a few inches away form the plaster in such a way that it won't blow and bump your work. This is removed! The second coat, some may call skim, will have a more finished look. This is achieved by the work, but also the mix may be heavier on lime, and the sand finer. Ready mix "fine stuff" is lovely to work with. This layer will be fairly thin. Watch out for cracks by the same methods of misting and damp cloth. Don't forget to use lime wash or lime based paint or the whole thing will be a waste of time. Lime plaster mixes are typically 1 part lime or to 2 or more parts sand.

1 comment:

toffelnigar said...

The typical homeowner will try to fix concrete crack repair with caulk. But this is only a superficial crack repair. Water will fill the inside of the crack and cause efflorescence, which will eventually loosen the caulk. In couple years, the caulk will start peeling. An alternative foundation crack repair method is to excavate and patch the crack on the exterior. This may not be permanent because all surface crack repairs will eventually get loose or crack.