Mortar is the stuff that goes between bricks to hold them together: without it, the building you’re in now probably wouldn’t still be standing. Mortar dates back thousands of years, and has been made out of many different materials throughout history, from mud to modern cement. Lime mortar has been used since the 4th century BC, in many places all over the world. More recently, in the 19th century, cement mortar was introduced. This became commonplace in the 20th century, and is now the default choice for modern buildings.
Lime Mortar
Lime is one of the oldest types of mortar, having been used in ancient Rome and Greece. This kind of mortar is made from a mixture of lime and an aggregate, such as sand. Lime mortars can often be found in older houses in London, especially Victorian or Georgian period homes. If you have an old home with lime mortar, it’s important to take proper care of it and not allow any inappropriate building work which could increase your risk of damp or structural damage.
Cement Mortar
Portland cement mortar became popular in the late 19th and early 20th centuries, and is now commonly used to construct new buildings such as those currently rising up all over London. This kind of mortar is made from a combination of Portland cement, sand and water. It is used in preference to lime mortar because it’s far stronger and can set a lot faster, which means buildings can be constructed more efficiently.
Your Choice of Mortar Can Cause Damp
Older houses often develop damp when they are improperly restored. Houses that were originally built with lime mortar are sometimes repointed with cement mortar, which involves having cement put on top of the lime, or replacing the lime entirely. If cement has been added to walls that originally used lime, problems will almost always arise.
Lime mortar tends to let walls ‘breathe’: lime-pointed brickwork can take in, but also release moisture from the atmosphere. If a house was made with bricks that aren’t particularly porous or breathable, then lime mortar offers an important way for moisture to make its way out of the house. When this is replaced with cement, moisture becomes trapped in the house and hey presto: you have a brand new damp problem.
If you have an older home whose walls have been re-pointed with cement and you’re suffering from damp, the solution could be to get rid of the cement and replace it with lime mortar. Having said that, we believe that all damp needs to be examined by a reputable damp specialist in order to safeguard your property, your health and your finances. If you live in Central, West or South London, we’d be happy to do that for you.
Call London Damp Company on 0207 127 6886 to book your free damp and timber survey.
