Hi Guys

Does anyone have allowable compressive stress values for bricks and blocks
used in 1970s construction please?
The blocks I have heard described as slag blocks - a bit like aero in
construction, but with black bits and solid chunks here and there.
Bit nasty to drill, but more solid/heavy that the modern thermalite jobbies.
The bricks I have heard described as Fletton (sp). Not sure if this is the
correct name, but these are bog standard 1970 house bricks.

Reason:

I am looking at an RSJ for ceiling joist support with one end landing on an
internal block leaf and the other landing on a
"previously-external-now-internal" brick leaf.
Need to assess end load support and any load spreading required.

TIA

Phil