Andrew Gabriel wrote:
In article ,
macon writes:

hello, I am planning to cut a larger opening in an outside wall made of
blocks. There is a large window at the moment and I want to install a
double french window.
I have permission from the building controls. I would like to know what
tools to use and how to proceed appart from supporting the load bearing
wall, which I know how to do. thank you.


If these are thermal blocks, a masonary hand saw goes through
them like a hot knife through butter, even if plastered (looks
like a regular timber saw, but with about 4 teeth/inch).
Actually, even a timber saw will work, but it will be wrecked
in the process and might not last for all your cuts.


Yeah second that.

Also, my builder mate claims to have cut the light thermalite type ones
with a handheld jigsaw as well ... but be prepared to buy a new blade!

However if its the external skin you are cutting then they are probably
medium density.

Almost backtracking a little ... I cut some medium density ones last
summer by scoring the surface with a small 4" grinder and then using a
bolster and club hammer to split them ... the difference was that I only
cut to a depth of less 1cm with the (small and easy to handle) grinder
and was I able to score all *around* the block for a clean break.

You might be able to get away with a scoring the blocks carefully in
situ, then drilling through the block on the scored line & using a
bolster and club hammer to split them out ... seems like a lot of effort
and will still kick out a surpising amount of dust.