Over time, wind and rain weaken the mortar between bricks…
letting in water to the joints…
which then damages walls. To stop this happening, walls need to be repointed periodically by removing
the damaged mortar and replacing it with …. … a good all-round general purpose mortar, like our natural hydraulic lime mortar. This not only looks good but lets walls ‘breathe’ so moisture can escape. It is also flexible so it is less likely to crack as walls gently move and settle. The first stage of repointing is ‘raking out’ … in other words, removing old unsound mortar from between the bricks to a depth of about 25mm … … or double the width of the mortar joint, if this is greater. You can do this using a hammer and chisel as here … taking care not to chip the brickwork… To avoid unnecessary damage, it’s often a good idea to leave sound mortar in place As lime mortar is generally soft … there should be no need to use machine tools, which could make unsightly cuts in surrounding bricks … or leave them needing to be replaced. When you’ve finished raking out the area to be repointed, create a clean surface for the mortar by using a stiff brush to remove any dust and loose materials from between the joints. Then thoroughly dampen the joints using water from a spray bottle. This helps the mortar stick to the brickwork and stops it from drying out too quickly. You are now ready to mix your lime mortar. For Lime Green Natural Lime Mortar you will need about a 7 kilogram bag per square meter of brickwork, and about 20 kilogrammes for stonework Each 25 kilograms then needs to be mixed with about 4-5 liters of water and, for between 3 and 10 minutes using a powered mixer. When mixed correctly lime mortar should not be wet, but ‘sticky’ so that it will cling to the underside of an upturned hawk. You are now ready to start repointing. For this you need a narrow pointing tool to press the mortar firmly into the joints between the bricks. Choose one that’s just a little narrower than the width of the joint so the lime mortar isn’t being left on the face of the brick. To finish the mortar you can use a stiff bristled brush to beat the mortar into the joints this gives a more open textured surface that helps the lime mortar
cure or harden faster Lime mortar doesn’t cure as quickly as cement mortars so normally it will take several months to reach maximum strength and durability. For the first few days lime mortar needs to be given extra protection from the elements. Gently spray it with water and cover it
with damp hessian sheeting in hot weather, so the lime doesn’t dry out. And covering it with protective sheeting in cold weather to prevent damage from frost To find out more about our natural hydraulic lime mortars, or any of our other lime products go to the Lime Green website at… lime-green.co.uk and click on the knowledge base tab, or if you would like to speak to someone about using lime mortar on your building
project, just call us on 01952 728611.