French drain and lowering external ground levels

[Estane]

I have an update on this that I need some advice regarding.

I've been liasing with the local council to try and fix this issue after it became clear that some of it was caused by next doors broken drain. After sending them the info about the steps and soil against the wall from next door, they advised that they do not agree that the house doesnt need a damp course and that standard practice in hosues of this age is to install a chemical one and to tank the walls.

Based on what I've learnt about older properties over the last year this would be a very, very bad idea, but if possible I'd like a second opinion.

Thanks

 

[Lacan07]

I have an update on this that I need some advice regarding.

I've been liasing with the local council to try and fix this issue after it became clear that some of it was caused by next doors broken drain. After sending them the info about the steps and soil against the wall from next door, they advised that they do not agree that the house doesnt need a damp course and that standard practice in hosues of this age is to install a chemical one and to tank the walls.

Based on what I've learnt about older properties over the last year this would be a very, very bad idea, but if possible I'd like a second opinion.

Thanks

Yeah, they don't know what they're talking about, sadly the majority of people will still be wedded to the modern methods of dealing with damp in old houses. You're correct in your assumption that liquid DPC's and tanking are inappropriate unless no other options are available (like cellars, etc)

 

[Lacan07]

I have an update on this that I need some advice regarding.

I've been liasing with the local council to try and fix this issue after it became clear that some of it was caused by next doors broken drain. After sending them the info about the steps and soil against the wall from next door, they advised that they do not agree that the house doesnt need a damp course and that standard practice in hosues of this age is to install a chemical one and to tank the walls.

Based on what I've learnt about older properties over the last year this would be a very, very bad idea, but if possible I'd like a second opinion.

Thanks

why do they expect you get a liquid DPC, surely your house (1910) has a slate DPC already?

 

[Estane]

There doesnt appear to be one at all except in a small bricked section underneath the bay window at the front - this was built much later than the rest of the property and the patio as it was is essentially inline/slightly below it. The house used to have air bricks and suspended floors like the other ones on the street, but previous owners blocked/removed those, laid concrete slab all through the ground floor over a damp membrane and then threw cement render at the walls until it wasn't showing anymore. The external rendering also has cement.

 

[Lacan07]

There doesnt appear to be one at all except in a small bricked section underneath the bay window at the front - this was built much later than the rest of the property and the patio as it was is essentially inline/slightly below it. The house used to have air bricks and suspended floors like the other ones on the street, but previous owners blocked/removed those, laid concrete slab all through the ground floor over a damp membrane and then threw cement render at the walls until it wasn't showing anymore. The external rendering also has cement.

View attachment 14233

It should be just above the air brick, can you see a dpc in your neighbours walls?

Anyway I'm guessing the faulty drain is on public / council property?

 

[Estane]

Rendering on most of them, but the ones that still have air bricks there's nothing. A handyman lives 2 doors up. A couple of years back he excavated his entire front garden and extended his front room with a bay window. He couldn't see any sign of one in his property either. He also had damp problems which cleared up after he built his own french drain at the back.

There were 2 damaged drains, one at the rear of mine and one at the front of the neighbour to the right as you at the front. I fixed mine as soon as I noticed it, next door left his overflowing for years before the council told him he had to fix it.

 

[Lacan07]

No worries, no dpc is nothing to worry about as long as you keep water away from the walls as you're doing already. A high water table can sometimes cause problems too

 

[Estane]

The front is mostly done, just a few wall blocks and coping stones to place - weather dependent.

I also had a further damp survey carried out last weekend. The report highlighted 3 main issues : poor quallity work on the valley and lead flashing where the roof at the rear section of the property meets the walls below the main roof, high external ground levels in my own rear garden, and the steps and ground level in the adjacent property. Over the weekend I finished digging up the old patio at the back and gravel down to the original clay, removed rendering all around the base of the structure - this uncovered a slate dpc hidden in the mortar joints - and also dug a trench out of the concrete slab in the kitchen along the wall that abuts the neighbours patio to expose the ground and help with evaporation.

There's one course of bricks immediately below floor level, foundation then clay soil. Next doors patio reaches about half up that first course and everything below that was soaked, so much so that the whole house stank of damp when I got up this morning. Seems to be drying quickly though. I've been monitoring it throughout the day and there is a constant source of moisture seeping through the bricks and the soil under the foundation, as suspected when I realised the ground height was a problem. The only logical explanation I can come up with is that ground water coming down the hill is getting trapped under his patio and then soaking into the side of my bricks - essentially the same as a hose pipe spraying the wall continuously.

Their patio is actually the same level as their internal floor, visible through glass in their rear door that I can see if I pop my head over the wall. However, convincing him it needs to be fixed is another matter. In my interactions so far he's been less than truthful, talking the talk to placate the council and making excuses but not taking action unless they force his hand.

I've emailed the report to both local building control and environmental health and am currently waiting for a callback from my legal adviser about next steps.

The surveyor also mentioned that having his patio so close to his internal floor levels would be a breach of building regs, but I'm having trouble navigating that particular maze.

In conclusion, this is probably going to get a bit messy.

 

[a twig]

Result finding the slate DPC! If the render / patio was bridging it that certainly wouldn’t have helped.

Had a similar problem in our current place - travails and my efforts to resolve here:

Hotel Dampifornia

You can check out but you’ll never leave! So, sadly had to sell our forever home in Somerset - moved to a newer house supposedly with no problems. Didn’t bother with a survey as have got bored of paying for ever more inventive works of fiction and so moved in to inevitably find daaaamp in the...

www.periodproperty.co.uk

Brushing back the bricks below it and repointing in NHL2 might also help.

Water seeping out might just be a lot that was trapped there rather than a source, fingers crossed! Smells should reduce as it dries out, fans blowing across the face of the damp areas will help speed things along.

 

[a twig]

Any way you can divert the water coming from the neighbour?

 

[Estane]

Any way you can divert the water coming from the neighbour?

Nope, already got a vertical dpc at the back of the house where the garden wall separating the properties meets the back of the house. Everything beyond that is his land.

 

[a twig]

Apologies, just re-read the thread you had already mentioned that, and you already have fans going, I’ll stop now

 

[Estane]

I had given serious consideration to jumping over the wall and smashing the patio up myself - deal with the consequences later - but new students moved in last weekend. Whilst I have no goodwill left for the landlord, I'm not prepared to inflict the distress that would cause on innocent kids just trying to get through their education.

 

[a twig]

Ha, this I can help with. Unless students have completely changed, offer several large packs of beer and a couple of sledgehammers to them to “help you fix the shared patio”

Then when landlord descends with vengeance upon hearing of his smashed patio you can say it was all a misunderstanding, they were meant to do your patio, not theirs, but in the spirit of neighbourliness you’ll make good on the confusion and get it all sorted out

 

[Estane]

I did not know how much I needed this until you posted it. Thank you for bringing a smile to my face

 

[Estane]

Sent the report to environmental health and they cited common enemy defense, which pertains to flood water not natural drainage, but they don't seem to care. They've refused to take any further action. Trying to involve my local assembly member, and if that fails it looks like game over.

 

[Estane]

Whilst I wait for the outcome of this I've decided to soldier on and try and tidy up the back garden instead.

At the moment the clay substrate is exposed and levelled to give it a slope towards the gully. There's been some movement of sediment with heavier rainfall which I plan to stop using a geotextile membrane and a type 1 base followed by gravel on top with a few paving stones for a walkway to finish, but I'm getting hung up about the height of the finished sub base relative to the gully.

If I drop the sub base on top of the current level then any water that gets through to the clay will still make its way into the drain natural - which will bring the ground level up a few centimetres. However, if I dig some of the clay out and lay the type 1 so that finishes just above the gully then any water that does permeate the type 1 will just sit on the clay with nowhere to go, potentially keeping the clay saturated indefinitely during wetter, colder parts of the year.

I appreciate I may be overthinking this and that evaporation should play a part, but considering the effort to implement I'd rather make sure I do this optimally first time.