Why use Lime?

Lime as a building material has been around for thousands of years. Until the 20th century almost all construction was done with lime mortar. When cement became widely available it meant that building work could take place much faster as cement cures much quicker than lime

So why is it important to use lime mortar for older buildings?

Lime as a binding material for mortar is hygroscopic ( it can hold water), and it can accomodate for movement within the building. As the building fabric absorbs and releases moisture throughout the seasons, the lime mortar can move with the stone/timber/cob etc.

Cement on the other hand is hydrophobic (it cannot hold water), it is rigid, and so as the building expands and contracts throughout the seasons, cement mortar will crack, trap moisture and will lead to decay, a downward spiral.

So what can we do?

The most common things we find are cement pointing , cement render (externally) and gypsum based plaster (internally). These need to be removed and replaced with lime based mortars. The building can then start to regulate its moisture again. Not only will this stop building fabric decay, it will also combat heat loss as a wet building is a cold building.

If you’re unsure if you have lime or cement in your building you can use this quick and easy method to find out. Take some of the mortar and put it in vinegar. If you see fizzing and bubbles it is lime, if not it’s cement.

Why not contact us, we’re happy to have a look and make a plan of action.