Trigs12 t1_je1i1dy wrote on March 28, 2023 at 7:00 PM

Reply to comment by NightElf193 in Rising damp from chimney? by NightElf193

Too many variables/possibles to really say over the internet. It might never dry out if the issue causing the damp isnt sorted, or you might be able to dry it out in good weather, but the next wet weather you get dampness again.

Could be high ground levels outside,causing damp to travel across especially if solid walls. If the specialist has recommended injected dpcs, high ground levels are the first thing id be checking.

But really, the specialist you've had out should be able to identify anything like that, and if you have any doubt, it may be worth a second opinion.

The injected damp course is something that splits opinions greatly. Some people say its great/bad. Others say rising damp is a myth entirely.

But at the end of the day, there is likely a reason for the damp in the first place, and that should be identified first, if the chimney fix hasnt been sucessfull.

NightElf193 OP t1_je1qr2z wrote on March 28, 2023 at 7:54 PM

We had another guy out today and he said similar, but believes the damp course is worn out and needs replacing. Upstairs and top half of the downstairs walls are bone dry so I guess rising damp is the answer.

When you say high ground levels, I may be sounding dumb here...but we live on a hill, is that what you were referring to?

Interestingly too, our garden is slightly uphill so rain rolls down towards the house, not sure if that could be a problem but I'd hope what that was taken into consideration when the house was built...it is a 1960s ex council house (I'm in England), I believe they were built well 🤞🏻

Trigs12 t1_je1v0sm wrote on March 28, 2023 at 8:20 PM

That should have been taken into consideration, when built. But thats what i mean about high ground levels.

Over the years, people tend to add new layers of gravel/soil etc on top of the old stuff, and now the ground levels are higher than what they should be against the building.

The dpc is generally 150mm above external ground levels. External ground level, depending on floor makeup, being 150mm at least below your finished floor height.

Assuming its cavity walls due to council house,cavity going down 225mm from your dpc (depending on floor makeup), the cavity should stop anything crossing over , but again, sometimes (usually when initially built) the cavity gets filled slightly with mortar/rubbish from the brickwork above being built, and you dont have a cavity, you have a damp bridge letting water soak across.

Combine that with your garden running water towards the house, and its a potential problem. Ground might not be high though, and just the dpc work alone, possible also some drainage along the house at the bottom of the slope might fix it.

I dont know enough about the old damp courses to comment on it being worn out. I think plastic dpc started to get used in the 1970's, so its possible yours is slate or some other material.