Repointing

Repointing Services in Essex

REPOINTING HISTORIC LIME BUILDINGS

Traditional Re-pointing Contractors specialise in Lime Mortar pointing and re-pointing, there is nothing better than seeing an aged, old building being reformed to its natural appearance and brought back to life.

Historic houses should be pointed in a flush profile.

Using the correct mortar… A builder may say you do not need to use lime, this is not true you must use preferable 3:1 ratio of sharp sand: hydraulic lime or a minimum 6:1:1 ratio of cement:sand:lime this is due to the way the building behaves.

Building behaviour… The building was designed to allow a certain amount of movement. It is malleable, letting moisture come in and then allowing it to be evaporated out naturally. The movement occurs with temperature and moisture changes in the environment. Lime mortar acts like a protection pad in the core of the wall.

Using the wrong mortar… If you allow someone to use only cement and sand on a historic house there are several things that will go wrong 

Firstly… the moisture which is allowed in through bricks or stone naturally will not be allowed to escape through the mortar because it is too rigid. So the moisture will have to escape through the brick or stone. This will cause severe damage to the brick or stone and with the frost, wind and rain the deterioration will happen a lot quicker. Following such damage, restoration is significantly harder and more expensive to repair and subsequently re-point again.

Secondly… if the re-pointing has been done without the use of lime and the pointing is harder than the bricks or stone it will create stress in the wall. This will in turn cause damage to the edge and faces of the bricks or stone due to the movement which it was designed to have, it will cause the mortar to crack and sometimes if serious these are referred to as death cracks .

REPOINTING NEW BUILDINGS

By the 1950’s most builders had given up using lime in buildings, they decided cement was quicker to use and more affordable.

New buildings are made to be strong and rigid, this however does not allow natural movement which makes the cement erode over time, they also have damp-proof courses, water resistant paint or cavity walls which acts like a barrier for a while against the elements.

These materials do not help when a small crack appears and then damp comes inside as it will not allow natural evaporation, which in turn creates more damp. Therefore re-pointing is needed to restore the structure and appearance of the building this would be done using a 4:1 ratio of sand and cement.