Specialists in Period, Listed and Historic Buildings

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Lime render

Renders were always originally lime based, keeping the stone, cob and timber dry beneath and allowing the walls to 'breathe.  Unfortunately, in recent years it has become common practice to use impervious cement rich renders. Because such renders are inflexible and non-porous unlike the traditional walling materials they cover, cracking occurs in the rendered surface, allowing water to penetrate and become trapped, causing stone, timber, cob and brickwork to remain damp and begin to decay. Any moisture rising up through the wall from ground level will also become trapped as most traditional buildings not only do not have a damp proof course but also have no cavities as modern constructions do today, this causes major problems, thus breathability is a must in any old building  to keep it at its best for many more decaces or centuries.

For these reasons never apply a cement rich render to old walls.

Lime Plaster

Similarly to the exterior of your old property, the interior of it also needs to be able to breathe for the same reasons, and again, with the emergence of gypsum plaster many properties are now found to have modern day  plasters and  emulsion paints  used to decorate.

These plasters cause the same problems as the exterior render and can often be spotted by areas of damp, cracking or where the emulsion will just flake and fall off.

The proper method of repair for such buildings,  most importantly on the ground and exterior walls is to use lime plaster. This is normally applied in a 3 coat method (although it does vary  depending on the background (wether it is wooden lathes, cob, or stone construction) but commonly the first coat is a haired coat of lime mortar which has horse hair in the mix, this helps to bond the background together, then there is a second coat of unhaired mortar followed by a fine finish coat  which can be trowelled or floated to  the required finish.
This should then be limewashed, distempered or an earth paint used to finish.

 

Sublime Renovations  Main Office:  9 Tip Hill, Ottery St. Mary, Devon EX11 1BE

Telephone:  01404 549065.  Mobile 07710 057954 or 07787 113466.  Email: info@sublimerenovations.co.uk