Damp victorian issues

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Damp victorian issues

Post by Sue2022 » Wed 18th May, 2022 2:52 pm

Hi everyone. New to the group and looking for much needed advice please. Feeling a bit out of our depth.
It's our first time owning an old house.
We have damp that has ingressed from high ground levels.
I've done quite a bit of research into damp and have the Haynes manual for Victorian properties which is very useful and we have a plan. Which I hope is the right way to go.
We moved into our 1893 victorian mid terrace three years ago. Our living room floor suddenly dropped an inch by the front door 2 weeks ago and we took it up to investigate. To our horror, all the joists along the external wall are soaked and rotten. It looks as if they had a previous damp problem and the joosts been replaced a few years ago but were put in touching the exterior brick wall and they hadnt lowered the external grounds.The soil and bricks under the sub floor are wet and there are gaps in the bricks where the mortar has completely gone. We have now lowered the exterior ground level, compacted soil, this week to 150mm below what appears to be a crumbly slate DPC or mud and 150mm below the joists. We have very high foundations and this depth has reached the horizontal brick which i presume is the start of the footings. The ground level was originally just above the slate DPC level.
The problem we have is that when the houses were built there wasn't a foot path in the road and over time the street and footpath outside have got higher than the footings of the house. We are intending to put in a gravel ditch along the wall and line with non woven geotextile fabric. However, our front yard is very small and there is only 3 foot between the house wall and the small wall next to the path. Our ground now that it's been lowered is 1 foot deep from the front pavement wall and we cannot angle a slope away from the house. If we keep the entire level to the right height , it would mean stepping down about a foot from the street, walking 2 spaces, then stepping up a foot into the house.
Does anyone have any advice please?
Can we build the level up beyond the gravel trench to the height of the public path?
We have cleared out the rubbish that was in the subfloor and checked the air brick( we have one) is not blocked. The airbrick is 2 bricks above floor level externally but comes out internally below floor level. Our wall is 12 foot long . We intend to put in 2 more air bricks, clear out all the crumbling soaked mortar and repoint with lime mortar.
Would this be NHL3.5?
Cut out the rotten joists and replace the joists.
Is this the right way to proceed?
We had the usual quotes for injecting a useless damp proof course. As you can see from the pictures it has previously had one wrongly installed above the DPC .
But, unless we fix the source of the moisture, external ground levels, then we won't solve the damp and I'm not sure how to proceed.

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Re: Damp victorian issues

Post by 88v8 » Sun 22nd May, 2022 10:07 am

Hello and welcome to the Damp and Other Things forum.

Jolly good plan. Bash on!!

I doubt the slate dpc has crumbled... more likely the mortar.

NHL3.5 yes... with sharp sand, not soft sand. I expect you knew that.

More airbricks, good. And are there sufficient airbricks at the back of the house?

The step down step up outside the door.... make a little bridge the width of the front door. Concrete lintels would be a cheap solution, or a chunk of stone from a salvage yard.

One question... the gravel ditch... where will it drain to? Or might it become a linear duck pond?


PS no pictures, alas. I think one has to have posted a minimum number of times...

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Re: Damp victorian issues

Post by paulc » Sun 22nd May, 2022 1:21 pm

The path from the gate to front door could be built up so that it is just below the level of the DPC sloping away from the house. Leave a small gap (say 2 inches) between the building and the path. The door sill will mask the gap to some extent and should reduce the amount of crud that builds up - Done something very similar with the paving around my house.

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