Suspended floor joists and damp

[SandTuft]

I’ve noticed that the honeycomb wall between the dining room and the sitting room seems to have most of the holes filled in with some kind of white powder, like chalk(/lime?) - any idea what/why/how and if I should remove it? It is surely blocking the airflow but I don’t understand how or why it got there in the first place

 

[Mr Chibs]

I'd clear it out, you want a good air flow through the wall.

Make sure you put a DPC between any wood and the brick sleeper walls, before loading your new joists on there... If you can't you could slide some bits under the joists, not as good but better than leaving it blank.

Thanks for the update.

 

[SandTuft]

Yeah I was thinking to dig it out, just really weird and wondered if anyone had an idea if what it was.

I’ve got a roll of DPC, will do! That timber on the near sleeper wall is just balanced there to check my levels, I’ll be putting a layer down when the timbers go in tomorrow. Thanks

 

[JP_]

Yeah, I had to clear out bucket loads of the stuff. Over 80s years of dust and dirt accumulation. Much from plastering I think!