Difference between revisions of "Lime Plaster"
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==Internal Lime Plaster== | ==Internal Lime Plaster== | ||
| − | Typically three coats of varying consistencies of lime mortar and plaster but can be four if a harling coat is also used and even five if the wall is uneven enough to require dubbing out. | + | Typically three coats of varying consistencies of lime mortar and plaster but can be four if a harling coat is also used and even five if the wall is uneven enough to require dubbing out. All coats are a mix of sharp sand and lime putty (i.e. 3:1 is three parts sharp sand and one part mature lime putty) |
| − | A thin 'harling' (or thrown) coat to provide a key and control suction (particularly on cob or brick) - optional (3:1 made sloppy with extra water) | + | * A thin ''''harling' (or thrown) coat''' to provide a key and control suction (particularly on cob or brick) - ''optional'' (3:1 made sloppy with extra water) |
| − | A dubbing out coat to fill any deep depressions where a flat final finish is required - optional (3:1 haired) | + | * A '''dubbing out coat''' to fill any deep depressions where a flat final finish is required - ''optional'' (3:1 haired) |
| − | A scratch coat, the body of the plaster, about 10-15 mm thick to roughly flatten the surface, keyed by scratching with a comb to provide a grip for the float coat. (3:1 haired) | + | * A '''scratch coat''', the body of the plaster, about 10-15 mm thick to roughly flatten the surface, keyed by scratching with a comb to provide a grip for the float coat. (3:1 haired) |
| − | A float coat to form a flat base, lightly scratched, for the final finish or top coat (3:1 unhaired). | + | * A '''float coat''' to form a flat base, lightly scratched, for the final finish or top coat (3:1 unhaired). |
| − | The top coat or finishing skim, much finer mix applied in two layers (2:1, 3:2 or 1:1 depending how fine finish is required using finer sand) | + | * The '''top coat or finishing skim''', much finer mix applied in two layers (2:1, 3:2 or 1:1 depending how fine finish is required using finer sand) |
YouTube Videos | YouTube Videos | ||
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==External Lime Plaster or Render== | ==External Lime Plaster or Render== | ||
| − | Similar to above, tends to be less fine finish and depending on weather resistance/water control may include a pozzolan in the scratch coat to give an earlier (chemical) set and also reduce water absorbtion/transmission. | + | Similar to above, tends to be less fine finish and depending on weather resistance/water control may include a pozzolan in the scratch coat and float coat to give an earlier (chemical) set and also reduce water absorbtion/transmission. |
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| + | ==Tools required== | ||
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| + | * '''Bucket''' - if required to carry harling coat slurry | ||
| + | * '''Hawk''' - wood or plastic to carry plaster to the wall and keep it 'fat' | ||
| + | * '''Plasterers Trowel''' - venetian trowels are easier to use on uneven surfaces as it has a thin blade and the corners are rounded and edges beveled so it does not catch as much as a standard trowel | ||
| + | * '''Wood Float''' - to smooth the surface and remove any tooling mark, also raised the texture slightly | ||
| + | * '''Devil Float''' - a float with a couple of lath nails driven through so they just protrude to provide a fine key | ||
| + | * '''Firm Sponge''' - used on the skim to finish the surface | ||
| + | |||
[[Category:Lime]][[Category:Plaster]] | [[Category:Lime]][[Category:Plaster]] | ||
Revision as of 02:45, 30 December 2015
Internal Lime Plaster
Typically three coats of varying consistencies of lime mortar and plaster but can be four if a harling coat is also used and even five if the wall is uneven enough to require dubbing out. All coats are a mix of sharp sand and lime putty (i.e. 3:1 is three parts sharp sand and one part mature lime putty)
- A thin 'harling' (or thrown) coat to provide a key and control suction (particularly on cob or brick) - optional (3:1 made sloppy with extra water)
- A dubbing out coat to fill any deep depressions where a flat final finish is required - optional (3:1 haired)
- A scratch coat, the body of the plaster, about 10-15 mm thick to roughly flatten the surface, keyed by scratching with a comb to provide a grip for the float coat. (3:1 haired)
- A float coat to form a flat base, lightly scratched, for the final finish or top coat (3:1 unhaired).
- The top coat or finishing skim, much finer mix applied in two layers (2:1, 3:2 or 1:1 depending how fine finish is required using finer sand)
YouTube Videos
How to lime plaster an internal solid wall by Artisan Fine Architectural Plasterwork
External Lime Plaster or Render
Similar to above, tends to be less fine finish and depending on weather resistance/water control may include a pozzolan in the scratch coat and float coat to give an earlier (chemical) set and also reduce water absorbtion/transmission.
Tools required
- Bucket - if required to carry harling coat slurry
- Hawk - wood or plastic to carry plaster to the wall and keep it 'fat'
- Plasterers Trowel - venetian trowels are easier to use on uneven surfaces as it has a thin blade and the corners are rounded and edges beveled so it does not catch as much as a standard trowel
- Wood Float - to smooth the surface and remove any tooling mark, also raised the texture slightly
- Devil Float - a float with a couple of lath nails driven through so they just protrude to provide a fine key
- Firm Sponge - used on the skim to finish the surface
