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So what's the big deal about lime?
In the past buildings were rendered and plastered using lime mixed with other ingredients.
The progress to using cement based renders and gypsum based plasters proved to be a bad move for people with traditional solid masonry walls (Stone, brick or cob). These non-porous products inadvertently resulted in the moisture which naturally exists in such walls being trapped. The moisture can evaporate from the surfaces of lime-based products.
It is incredible to see how wet walls can be when the moisture is trapped by cement and gypsum and so is how effectively they dry out as soon as they are replaced.
Secondary benefits are that the flexibility of lime can more easily cope with movement which often occurs in the walls of older buildings, which can lead to less cracking.
Renders are used to protect and/or improve the aesthetics of exterior walls.
Render options:
Renders can be applied in a range of styles. Stucco, scraped and bagged, grinning stone, rough-cast tyrolean and hand-thrown styles. This is an important aspect as the greater the surface area, the better the render will function because more evaporation will be possible. The rougher the better.
The constituents of renders can be varied to give colours to suit the natural tones of the locality. Aggregates of a particular size or colour may be included. We can analyse the component parts and produce a match. In the past we have even used washed local river gravel and have dug the exact colour-match sand from the local ground to create a perfect match of existing renders on special buildings. Existing renders can be patched and/or repaired to conserve them. Historic renders could be stitched back to the building or consolidated in special cases where it is preferable to save them.
Limewashes:
It's essential to use porous decorations to work with the lime. The limewash can be used to add colour and protection to lime renders. A range of natural binders can be added including casein from milk or tallow from animal fat.
An alternative to limewash initially is to use a self-coloured render. Ask us for more detail.
Limewashes can be applied inside and out although commonly a distemper is used internally as they do not have a dusty surface although they are lime-based so still porous, but well bound.
A full range of natural colours is possible. We can advise on what colours are traditional and would have been used to decorate historic properties in your locality. We can mix a lime-wash for you to match existing colours.
Laths:
Plasters can be applied to brick, stone and cob and where walls are not solid wooden or stainless steel laths can be supplied. Timber laths are often supplied at sawn oak, but can be sawn softwood or riven (naturally split) oak or chestnut .
Arrises around windows and external corners such as chimney breasts can be formed with traditional wooden dowels or can be free-formed to a radius.
Plaster can be smooth finished or have a rustic grainy finish.
Existing lime plasters can usually be saved and ignoring what many may have advised you, it is usually worth asking a conservation company specialising in lime BEFORE the supposedly failed existing plaster is hacked-off or ceilings are pulled-down. You are likely to save thousands of pounds. Frequently plaster can be saved or is perfectly serviceable. Costs and project time can be saved.
Decorative Plasters:
Some historic buildings have fine decorative plaster features both inside and out. These can be repaired or created new. Photos show some examples. This could be a decorative ceiling, cornice, window mouldings, ceiling roses, pilasters, capital mouldings on columns or other features. We can often repair the features in-situ, but on occasions it is necessary to take mould impressions and cast new items off-site and fit them later.
Clay and mud plasters:
We can supply and apply compatible materials which were often used in earlier and artisans buildings.
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