should cavity wall be empty?

[bof]

I'm just trying to deal with a damp problem and have taken a few bricks out of the cavity and removed a half brick that was bridging the cavity above the dpc.

There doesn't appear to be a damp problem other than the one which was where the half brick bridged above the DPC.

However here is more debris in the cavity below the DPC and AFAICS all of the cavity below the DPC is to be filled with a loose sand mix, and general lumps of mortar, so I guess this is from the original house build.

I don't know if the inner course of the cavity wall has a DPC or not, I can't see one.

So my question . . . is it normal or abnormal for the cavity to be filled below the DPC?

The house dates from the 1880s

MTIA, if replying by email please use address in sig

[Set Square]

I'd say it was pretty unusual for an 1880's house to have a cavity wall of any sort - I would expect the walls to be 2 (9") or 3 (13.5") bricks solid. If there *is* a cavity and dpc (slate?) then hopefully both leaves have a dpc. In this case, bridging the cavity below dpc level is not really a problem.

Have you considered cavity wall insulation? You can probably get a grant to help towards the cost - and it could have a significant effect on comfort levels and heating bills.

[PJ]

I'd say normel because on my "new build" the cavity below DPC is filled.

[bof]

In message , PJ writes

Thanks for that, puts my mind at rest and saves me a hell of a lot work.

Any other feedback on this?

[bof]

In message , Set Square writes

Nope definitely a cavity, caused the surveyor some puzzlement when we bought the house as the outer leaf is laid using alternate half and full bricks, so that the brick pattern looks like a solid wall, however there was also cracking characteristic of wall tie corrosion (which has since been resolved)

[Christian McArdle]

Jammy git. The Victorians didn't normally build cavities, but did sometimes, particularly when a particular damp issue was predicted (i.e. very exposed location, or built into a hillside). I can imagine that certain local builders might have had a penchant for them, as well.

Christian.

[bof]

In message , Christian McArdle writes

In this case it was probably due to the fact that the local builder was building his own home, all done with nicely tucked pointing too, which unfortunately some 20th century monkey ruined three walls of when they repointed.

[N. Thornton]

hi

Whether the sand etc is a problem depends on where the DPC is on the inner leaf, and whether there is one. In short it may well be a problem, but I couldnt say for sure without inspection. Ie clearing the junk seems like a sensible move if its practical to do.

Cavity wall Vic houses are no rarity, contrary to popular myth. Although the majority were solid wall, lots of Vic cavity walls were built. In fact ratbond only comes in the cavity variety. It is odd indeed that so many people that ought to know think Vic walls are automatically solid.

Most popular cavity constructions were half inch cavity, designed to stop damp ingress, not for insulation, and ratbond which is a bridged

4" cavity construction.

Regards, NT

[Jerry Built]

WTF is "ratbond" ?

Erm...

NT, if you are suggesting that any significant fraction of Victorian buildings were purposely built with cavity wall construction, have you any on or off line support for this extraordinary theory? I should be interested to see any.

[Christian McArdle]

I don't think they were common, but they were certainly used when required. My parent's house (~1888) has cavities, although only on the lower ground floor and for obvious damp proofing reasons. A number of posters on this newsgroup have reported finding Victorian cavity walls. It appears that they are more likely found on higher quality properties and those with expected water penetration issues.

Christian.

[N. Thornton]

Its a type of brickwork. See if I can sketch it, birds eye view of:

_______ |_______| | | | | | | | | |_|___|_| |_______| | | | | | | | | |_|___|_| |_______|

there we go. The bricks are all used on their sides, so less bricks per area are used, and theyre assembled in this interlocking cavity wall pattern. It gives a 4" cavity and is probably the most economic double skinned brickwork available, except for rubble walls.

I think Christian beat me to that one. I have also seen them myself, and the books I have on the subject talk about half inch cavities being an extra option for improved dryness. While the majority were solid, cavities are by no means rare.

Regards, NT