Lime Pointing
Lime Pointing Edinburgh
Why should I use lime on traditionally built buildings?
Lime pointing has certain characteristics which makes it the most appropriate material for repairing buildings constructed or finished with lime. Lime mortars allow ‘traditionally constructed’ (mass wall) buildings to ‘breathe’, unlike modern OPC mortars which can be virtually impermeable to moisture, trapping it within the walls and leading to dampness and decay internal.
Why cement pointing bad vs lime pointing
Cement pointing traps the moisture, which through the action of frost and the concentration of salts accelerate the decay of the stone.
Cement-rich mortars, like these, will set harder than the stone. Cement mortar is less porous than stone, so moisture gets trapped in the stone and evaporates at the stone face, causing it the weather rapidly and over time leaves the pointing standing proud of the stone. Cement-rich mortar prevents the stone and bricks from expanding when warmed by the sun, causing the stone to break up more quickly.
In addition to damaging the stonework, cement-rich mortar looks out of place as it is often a grey or off-white colour which does not complement the colour of the stone and is in most cases too strong for the masonry units. For more information on our Lime Pointing services, please contact us.
Lime Pointing FAQ
Lime mortars allow ‘traditionally constructed (mass wall) buildings to ‘breathe’.
Things to look for on your building lime pointing vs. cement pointing
- Stone erosion around hard cement pointing
- Missing or loose pointing on the stonework
Likely cause of damage to the building
- Old decayed lime or cement pointing
- Cement pointing prevents evaporation and causes saturated stonework
Suggested repair works
- Selective repointing of masonry units using traditional lime pointing Edinburgh
- Carefully remove cement pointing and repoint with lime
Key Points for lime pointing vs. cement
- Lime mortar is more porous than cement mortars
- Lime is breathable cement is not
- Historic buildings are frequently constructed with relatively soft masonry units and many types of stone and minor movement in such buildings is quite common. This movement breaks the weakest part of the wall, and with cement mortar, this is usually the masonry unit. When lime mortar is used, the lime is the weaker element and the mortar cracks in preference to the masonry.
- Non-hydraulic lime takes longer to set and should not be allowed to freeze before it is well set. Although the setting process can be slow, the drying time of a lime mortar must be regulated at a slow rate to ensure a good final set.
- A rapidly dried lime mortar will result in a low-strength, poor-quality displaying shrinkage cracks. In practice, lime mortars are often protected from direct sunlight and wind with damp hessian sprayed with water to control the drying rates.
Can we carry out lime pointing in the winter ?
WHAT IS THE PROCESS
Our Edinburgh team will check your stone wall or stone and brick wall to have a closer inspection of the existing mortar
Then we can send your edinburgh lime to the Scottish Lime Centre for a closer inspection to try and find the based mortars type for a additional fee of £980+vat, this allows you to tray and match the existing as close as possible
Then we can use traditional methods to replace your mortar with new lime