"Lobster" wrote in message
m...

I'm currently bricking up two doorways in a 4" party wall between two
terraced houses, as part of a project to reinstate the original
dwellings. I did the first one using medium density blocks, which I
lugged back from Wickes myself, nearly stuffing both my back and the
car suspension in the process... a joiner who later surveyed my
handiwork said I could/should have used the much lighter aerated type
instead. Is that right? If so I could at least use those for the
second doorway!

When we had an extension built a few years ago, with a cavity wall, I
remember the builder used heavy blocks for the outer wall and much
lighter ones for the inner - I assumed I'd need the heavier ones for
the doorway.

I've just noticed in the latest Wickes catalogue (page 36) both types
of block are described as "3.5N" - would that be their load rating?

If between two dwellings, use high density concrete blocks for sound
insulation. Houses normally have lightweight high insulated blocks on the
outer walls and the cheapest blocks available on the inner walls. It is
best to have dense concrete blocks on inner walls to give a higher thermals
amass.