damp course???

[Gill Smith]

my 1950's ex-council house is damp at the gable end

a previous occupant extended the garden right up to the end wall

the soil being 3 inches below the top of the original bituminous-coated brickwork

on digging I found the bituminous brickwork encased in a cement coat

from the bottom of which protruded a black plastic liner

which extended UNDER THE GARDEN!!!!!

resulting in a 12 in-wide 18 inch-deep plastic lined trench along the end wall

at the bottom of which were puddles of water

this *cannot* be right, surely???

--

[John Williamson]

Sounds like a good way to make a cheap pond. ;-)

But that'll be what's causing your rising damp, by the sound of it. Let's hope your electrics are as cheap and easy to sort out. It is possible that the cement coating and plastic were a previous DIY attempt to bodge round a previous damp problem, though.

The minimum recommended distance of the DPC above local ground level is

6 inches (150mm for the non-imperialists.)

[Gill Smith]

what is really troubling is that the cement casing is *very* well done

obviously by someone who knew what they were doing

- when it came to cement casings!

--

[Tabby]

The plastic trench sounds very weird. A simple option is to dig out a trench next to the wall and fill with gravel. That lets air get in there to dry things out.

NT

[Gill Smith]

no more filled trenches for me!!! :(

I want to get back the original bitumen-coated brickwork

(i.e behind the cement casing and its embedded plastic liner)

and put down some hard paved or concrete surface where there's presently 'soil'

which isn't soil

it's the impenetrable clay muck you see 10 yards down when they excavate motorways

--

[Tabby]

Sounds like subsoil. If you concrete over it though, I'm not sure how much you will have gained, in dryness terms.

NT

[Gill Smith]

I misunderstood you

you mean get down to the original soil level and dig a trench into that and fill with gravel

(I thought you meant backfill gravel into the trench I've just dug into the raised bed)

yes, a gravel-filled trench is a good idea

will investigate

--

[Gill Smith]

sounds drastic!!! but if it has to be done, so be it

the surveyor's report mentioned possible cleaning/clearing the cavity wall

but didn't explain how

maybe I could tie it in with replacing the downstairs single-glazed windows

--

[Tabby]

Its unlikely you'd need to do that. Just start with the basics and sort out the external soil conditions and remove the impermeable coat on the wall so it can dry off.

NT