Lime Render and Mortars have existed as a natural product for centuries, which have proved the test of time - in that they were the original materials used in the building of ancient and historic buildings that still exist today - such as Castles and Churches.
The reason Lime is such a good material is that it allows the building to 'breathe' - allowing moisture to move in and out without causing damage to the sub-structure, ie; with Stone and Cob constructions - especially important when no damp course exists.
The modern application of Cement however prevents this moisture movement which can then lead to damp build up, render seperation from walls, frost damage, cracking and general decay of the surface render and sub-structure. This is because moisture gets trapped behind the cement, (through condensation, capillary action from the ground or flaws in the original cement plaster or mortar etc). Once water is trapped it can cause damage by expansion due to freezing and saturation which can result in the decay of the sub-structure, ie; with Cob, Brick and Stone.
Stephen mixes all his Lime Mortars and Plasters by hand on site to the requirements of the particular medium. He uses Natural Hydraulic Lime for his fresh mixes, and Quick Lime products as required, eg; Lime skims and Lime Wash Paints. Different strengths of 'NHL' are used dependent on the material it is being applied to and for what purpose, eg; Stone, Cob, and Straw / Pointing, Plastering and Flooring.
Typical applications involving Lime are:
Listed buildings often require the traditional use of Lime products as part of their restoration and maintenance (and in compliance with conservation officers recommendations). Many building insurance policies also require the correct usage of mortar and render appropriate to the building. Where we are located in the heart of Devon, Cob buildings have stood the test of time for centuries (often in excess of 400 years) without damage until cement was widely adopted as a new method to renew or repair - over the past 50 or so years - without the understanding at the time of the potential for sub-structure damage.
These methods are the recognised Traditional Skills that most conservation bodies need in order to maintain the integrity of the local vernacular. Modern structural engineers experienced with such buildings recommend these traditional methods.
Much of our work now involves putting right and making good the damage caused by the use of cement, and the reinstatement of Lime as the correct plaster or mortar.