Lime is a beautiful product to work with, and is lovely to use if you follow the correct steps. Most of our work is using lime putty, this is more flexible than NHL, we use various firms for our lime supplies. The most important factor to ensure a successful lime plastering project is to ensure the wall has dried down to lower the risk of hygroscopic salt staining. We excel at this as a qualified drying Company that use state of the art desiccant drying equipment, along laboratory analysis to measure moisture by quantitative means. We often see some firms applying lime plaster to salt contaminated soaking wet walls that give the appearance on the surface the wall is dry , this is when we find a higher rate of failure. Using our tried and tested methods we have a huge success rate, and also the walls dry down quicker ensuring decoration can be carried out quicker.
The general rule is to apply 4 coats internally and 3 coats externally.
The first coat is a scat coat, which is a soupy consistency of 3/1 unhaired lime mortar, this is harled onto the walls for a key. You allow this to dry and go white, before starting the next coat.
Second coat is the scratch coat or otherwise known as the dub coat, this is the 3/1 horse or goat hair coat, this can be applied up to 20mm thick at any one time. This coat is scratched then scratched up. Once you are happy with this coat you allow to dry/ cure.
Third coat & final if external, is the 3/1 unhaired float coat. Applied at a depth of 6 – 10mm depending on what’s required. This coat after being troweled on and worked well is then floated with a polyurethane float or a wooden one, now this is the important part…… at no time can you rush lime, it’s a traditional product which carbonates to cure.
Fourth and final coat for internal use…. is a lime putty 3/2 lime skim which is applied wet on wet and each layer no more than 1.5mm so an overall depth of 3mm. This can be a tricky one to do as it dry’s fast, but you keep misting with water to keep the skim as workable as possible and try to have a cool room, ideally.
All external work lime rendering is to be protected with hessian and dampened down as necessary.
If you fancy a warmer wall we also offer hemp lime plaster, this can be used on any traditional building, timber frame buildings as a replacement for wattle and daub, or ecological new builds. The reason only half of the wall has been replaced with hemp lime plaster is because of a significant dry rot problem. Above this is hemp lime plaster finished with a lime wash.
All decoration should be using lime wash or clay paints, these will allow greater evaporation than vinyl paints.
We offer free advice when it comes to lime plaster. If you require internal or external lime plastering give us a tinkle 🙂