Hello PPUK,
I am planning on casting a window cill in situ to replace the very knackered cement cill that was installed at some point. As you can see from the photos the wall was in a pretty sorry state behind the render but this has been remediated with the help of several meters of helical bars and will be repointed in a matching lime mortar.
The dodgy cill was removed and the brick work repaired. Unfortunately the cement cill had been trapping moisture for decades and so part of the original box sash timber cill was completely rotten. We cut out the worst of the rotten timber and will plant an oak cill extension to replace the rotten timber.
Before doing this though I am thinking of casting a new cill in the space vacated by the cement cill and perished old bricks. The replacement oak cill extension can then be installed on top of the newly cast cill.
Much of the internet suggests using a mix of cement and ballast for the cast cill but I am wondering if it would be an advisable to cast one with NHL and sharp sand. I have some NHL 3.5 left over and thought about a 2:1 (sharp sand:lime) mix for the cill. This would be similar to the mix we used for the limecrete floor but only using NHL 3.5 in place of NHL 5.
Has anyone undertaken something like this?
Many thanks.
I am planning on casting a window cill in situ to replace the very knackered cement cill that was installed at some point. As you can see from the photos the wall was in a pretty sorry state behind the render but this has been remediated with the help of several meters of helical bars and will be repointed in a matching lime mortar.
The dodgy cill was removed and the brick work repaired. Unfortunately the cement cill had been trapping moisture for decades and so part of the original box sash timber cill was completely rotten. We cut out the worst of the rotten timber and will plant an oak cill extension to replace the rotten timber.
Before doing this though I am thinking of casting a new cill in the space vacated by the cement cill and perished old bricks. The replacement oak cill extension can then be installed on top of the newly cast cill.
Much of the internet suggests using a mix of cement and ballast for the cast cill but I am wondering if it would be an advisable to cast one with NHL and sharp sand. I have some NHL 3.5 left over and thought about a 2:1 (sharp sand:lime) mix for the cill. This would be similar to the mix we used for the limecrete floor but only using NHL 3.5 in place of NHL 5.
Has anyone undertaken something like this?
Many thanks.
