Lime Pointing ~ Summer 2008 – part 3

Whilst not wanting to become a lime-pointing-bore (I bet there aren’t too many of those in the world) I feel another update is in order.

The tools that I ordered to help in raking out the mortar joints have disappointingly not arrived yet but the repointing tools have. I managed to break the mortar hawk as soon as I took it out of the box so it didn’t score highly for resilience, but it’s nothing a drilled hole and suitably sized bolt can’t fix. More on the pointing gun below…

I’ve tried some innovations to my repointing technique with good and bad outcomes…

Whilst despised by many as water wasting and noisy, I found using a pressure washer to clean out the joints and dislodge loose mortar before hacking out, then tidying up again with the pressure washer saves time and leaves clean, well-prepared joints ready for re-mortaring. (Sorry about the noise and wasted water).

Don’t use a cement mixer to mix lime putty and sand – it doesn’t work, you just get blobs of putty encased in sand rumbling round-and-round in the mixer. I know everyone who knows anything about lime mortar knows this one – I just had to prove it for myself.

A mix of 3-1 sand to lime putty doesn’t work in a pointing gun (an over-sized version of the sealants guns that we all know) it just compresses the mortar and squeezes out the water. I think the problem is a combination of not using a plasticiser and / or the ‘wrong type’ of sand – I just used standard building sand. As the plasticiser supplied was not to be used with lime and the instructions for the gun say not to use sharp sand I’ve hit a bit of a (stone) wall with this one. I might try messing around with the mix (less sand or a finer one). Anyone know if there is a plasticiser suitable for use with lime?

The saga continues…






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