Drainage - French drain query along low dpc wall

[Joey39]

Seriously need some advice from drainage experts. I've got a 8 m long external brick wall with very low DPC. Neighbours path runs along whole length. I have cavity wall insulation. Path is at DPC height with 4-6inch gap all along between their path and my wall. I need to infill with drainage material ?pea shingle. How deep do I dig? Do I line bottom of trench with permeable fabric to keep soil away from shingle? Is there recommended shingle size? Neighbours want to top with decorative cobbles larger than my preferred choice but am concerned re splash effect. What size max can I let my neighbours top with? Should I be concerned re splash effect can you explain? I will dig with a slight gradient, over 8 m length how much fall should there be? Do I need to bother with drain pipe with holes or will just trench with pea gravel suffice. This wall is quite sheltered about 90-100 cm from neighbours house so not too exposed though it is a north wall. I plan to do this myself obviously labour intensive but otherwise cheap enough. Just need help. Single lady in a predicament as neighbours renewed path and didn't create suitable drainage along my wall but luckily there is a 4-6 inch gap for me to deal with. Hopefully easy enough if someone explains how? Many thanks - hopeful Joey. (I am sure my neighbours will help me too!!!)

[seanandruby]

have a read of this Joey

[Tony McC]

Have I understood this correctly? The neighbour has had a path installed against your external wall, and the path has been laid at a level flush with your DPC?

If so, then they are wholly responsible. They cannot breach Part C of Building Regs in relation to a propertry they do not own.

[Joey39]

Thanks tony mcC - yes actually two courses higher than my dpc. Original path was along same level as dpc but they built new path on top so it's now 2 courses higher. But we've cleared a gap 4/5 inches wide all along and need to sort drainage solution out. I don't suppose I can send you images ? can you quote me actual phrase in building regs part c that relates but to be honest I don't think I can force neighbours unless legally through solicitors which I don't want to do as I know it can get nasty and costly.

[Joey39]

Tony mcC sorry to be ignorant and thanks for your advice. How or who enforces building regs part c on my neighbours who have totally disregarded building regs when building path and block pave drive adjoining my external wall. Is it local authority? I rang them and they didn't want to know. The construction didn't need planning permission so is it correct that no one can enforce it. The construction was done 6/7 years ago am I too late to enforce anyway? Also is there a section in building regs that relates to adequate drainage when it affects a neighbouring property? It would be useful to know the exact sections as I am finding it a mine field! If I quote these (print outs) for neighbours they may actually sit up and take notice. So far they tell me it doesn't rain that much and when it does it drains and only 1 course below dpc is adequate and that splash effect doesn't exist and large cobbles are better than pea shingle for drainage so I am fighting a losing battle and had confrontations again today. Help!!! :😡

[Tony McC]

If you have a mortage, your mortgage provider may well be very much inclined to take action against any third party threatening the structural integrity of what the mortagage co regards as *their* property.

Local authorities are screwed to buggery and back by central govt slashing public spending to pay for their chums, the greedy bankers and hedge fund managers, who can't possibly be expected to cover the cost for their own cock-ups, and so LA's just don't have the funds to police retro-breaches of Building Regs. Instead, it is down to you, the property owner.

You could fund your own legal action, which would involve getting a professional assessment of the situation and it's likely impact on your property. Any competent building surveyor (you'd be surprised at how many incompetent ones there are out there!) should be able to do this.

Presenting the report to the neighbour *may* induce thjem to rtake remnedial action but it may harden their resolve and need you to involve the courts, again at your own expense. However, were you to win, costs are very likely to be awarded to you.

The alternative, as already mentioned, is to see if your mortgage provider and/or buildings insurance provider would be willing to take action on your behalf. After all, any damage to the property threatens their own investment so it is in their own interest to ensure the property is not compromised.

[Joey39]

Ok thanks but alas I don't have a mortgage (lucky for some I suppose) and have had loss adjuster out already and my buildings insurance won't cover. Basically the house originally must have been built with a low dpc, which at the time I am assuming if building regs have always recommended 2 bricks above ground for dpc, must have been over looked at the time by building inspector. It was built mid 1970's. Can I complain to anyone now all these years later. Nhbc or equivalent ? My neighbours only have to pressure wash their path once a year to saturate my wall above dpc and I suppose the damage will have then begun. I may just complain to local authority in writing and see where it gets me. Maybe they would at least visit the property to take a look and give us both free advice! ( neighbours are on benefits and don't want to pay for anything and I presume may get legal aid if I went down route with solicitors) I am beginning to think I am the poor innocent victim here who may suffer losses when I try to sell in years ahead or deal with potential future rising damp. A company called Peter Cox have been out and trying to sell me injectable substance to raise dpc by 2 or 3 bricks and say this expands into cavity and along mortar lines to provide another raised dpc. A surveyor I spoke to said keep away from that. Apparently it is done through chemical reaction - sounds far fetched but will it work - if you have any experience of this or have any views please let me no !!! Many many thanks nice to share this problem with someone.

[Tony McC]

The 'two below DPC' principle was well-established in the 70s - that's when I started in this trade!

NHBC only cover new builds, and then only for 10 years, and less if they can get away with it.

LA can't and won't intervene - it's a private property and, technically, none of their business.

Keep away from any retro-fitted DPC solution: they rarely work anywhere near as well as they promise.

Get a building surveyor to confirm the cause of the problem and then you can decide what to do.