Pointing simply refers to the mortar in between the masonry of the building, whether it be stone or brick. More often than not it is the case of re-pointing, whereby a traditionally built house has been pointed in cement and has since been the cause of internal damp, it then becomes necessary to remove the cementitous materials and 're-point' using a lime mortar that will allow the building to breath more effectively.
Lime pointing is a sufficient finish to a building, especially if the building is sheltered from heavy weathering. However, a heavily pointed stone building looks beautiful if then given the added protection of a limewash.
- Stone built buildings; Stone has always been used to build as it offers huge benefits to the structural strength of a building, and were historically locally sourced. In its simplest form, a stone building will use quarried 'rubble' stone, this type of stone will be not be 'dressed' and may therefore not be overly aesthetic, it is in this case where the exterior will be given a coat of render or limewash to hide its simplistic vernacular nature. At the higher end of building with stone, top quality hard stone, often much larger than those used in vernacular design, would be 'dressed' to given a more attractive finish.
- Brick built buildings; Whilst brick is probably the most commonly visible building block in the modern world, it only became used widespread within the construction industry from the 18th century. They have been used to make some incredibly breathtaking structures, achieved by combining various coloured bricks as well as using highly aesthetic bonds or combinations of them. Some brick buildings also incorporate gauged brickwork to create highly decorative features, a common approach in the Georgian period. If a building is well sheltered or even just one aspect of the building, an appropriate approach would be to allow the building to breath as much as possible by not covering the walls with any additional extras such as renders or limewashes but leaving it tightly pointed. As part of our pointing service, we will endeavor to match the mortar of the building as best possible, replacing like-for-like ensures the least visible scar of intervention.
Limewash is used to protect our buildings from the elements by providing layers, in some cases several layers, of protective barriers that take the form of calcium carbonate. Limewash is simply a mix of pure lime putty and water. When required, a limewash can have a pigment added to provide colour, and in some cases a substance such as tallow to increase the waterproofing ability.
The strength of the limewash comes in layers, as its effectiveness at preventing water ingress becomes more evident as each layer carbonates and therefore increases the paints resistance to water penetration. A new lime render will require at least 4 coats of limewash.
Limewashing is a simple concept, but a crucial process to get right. Limewash offers very little opacity when first applied, giving the effect that it is more translucent that it will actually be once it has both dried and carbonated. Limewash must be applied thoroughly and efficiently to ensure adequate covering, as it is THE final step in protecting the surface from water penetration but also 'shadows' very easily if not applied properly.
In extreme circumstances the waterproofing ability of limewash can be 'strengthened' with the addition of Tallow, which is a form of animal fat. The Tallow is added to a 'hot mix' of limewash where it melts and thus becomes incorporated into the mix. Once the Tallow mix is applied to a surface it becomes significantly less permeable, however, bare in mind that any reduction in permeability is also a reduction in breathability.
It is possible to achieve a variety of limewash colours by adding pigments to the mix, these pigments are naturally occurring minerals and are clay based. They come in the form of Sienna, Ochre, and Umber. All three of these pigments offer a variety of colours when combined with each other, but all variations facilitate an 'earthy' palette. In order to achieve more lively colour variations, manufactured pigments are incorporated and offer a more extensive colour range. An important point to note with limewash is that it will discolour when wet! The tonal aspect of their colour will darken by around five times that of its dry version. This, at least in my opinion, is the beauty of a limewashed building, as it adds to its character. However, people are often surprised by the affect that water has on a limewash, as modern plastic paints provide that uniform finish we are all familiar with.