French drain help please?

johneym

hello Folks,

A few questions if anyone has time please.
A lot of water around my old recently bought cottage when there are heavy rains. Up to 14 inches.Very low site. Land much higher at back and one side of cottage, but sloping gently from front of cottage. There is a drain 30 metres in front of cottage and site slopes gently in this direction.This part of site is very rocky and compact and not easily drained.Has also had years of topping up with 803 and is rock hard.
I want to do a French drain around house and bring water through the compact section to the drain in front.

1)Is 3 inch yellow pipe ok for this?
2)What size stone?
3)Trench size? Depth?
4)The gutters run directly onto ground so can these be directed into French drain outlet?

Many thanks for your valued time.

148multi

johneym wrote: »

hello Folks,

A few questions if anyone has time please.
A lot of water around my old recently bought cottage when there are heavy rains. Up to 14 inches.Very low site. Land much higher at back and one side of cottage, but sloping gently from front of cottage. There is a drain 30 metres in front of cottage and site slopes gently in this direction.This part of site is very rocky and compact and not easily drained.Has also had years of topping up with 804 and is rock hard.
I want to do a French drain around house and bring water through the compact section to the drain in front.

1)Is 3 inch yellow pipe ok for this?
2)What size stone?
3)Trench size?
4)The gutters run directly onto ground so can these be directed into French drain outlet?

Many thanks for your valued time.

Use 6" perforated cori pipe, 3"to 4" drainage stone from a sandpit, fill to the top with stone. Let gutters into nearest point of French drain and put manhole there and at each corner. Cori pipes can be cleaned with power hose if they get blocked. Put a small bit of stone under the pipes with correct falls. 6" trench.

johneym

thanks Multi,

at the end you say a 6 inch drain? Is this not too narrow? Smallest digger bucket is wider than this? And how deep should it be approx. Thanks again.

_Brian

Lots of what your asking will be answered by hiring a good experienced digger driver when your ding the job.

They will have years of experience assessing sores and installing drainage including depth and falls required.

I agree with above that min 6’ corry pipe, we installed 9” at our house because I’m only doing it once.

Yes turn all down pipes into the drains, that’s why I’d go for 9” as it will take the water from down pipes and the ground area and whatever is coming in from behind you.

Don’t worry abkut the trench being wider than the pipe as it will be filled round with clean stone To help drainage.

Can’t stress how important getting the right man on the machine is. He will safe time and money.

johneym

Thanks Brian,

Whats the ideal size trench for a 6 inch pipe? A foot bucket?

I have a guy who wants to do it but he has a very big machine. Just not sure how close he can get to house walls with such a size. It's very tight too between walls and fence, I don't believe he will have any room to manouver on 2 sides of house, let alone do any work. Also the impact of the vibrations etc on the old walls and foundation. It's a 13 tonne machine.

johneym

thanks for the replies lads,
I'll be starting this in 2 days time.

minerleague

johneym wrote: »

hello Folks,

A few questions if anyone has time please.
A lot of water around my old recently bought cottage when there are heavy rains. Up to 14 inches.Very low site. Land much higher at back and one side of cottage, but sloping gently from front of cottage. There is a drain 30 metres in front of cottage and site slopes gently in this direction.This part of site is very rocky and compact and not easily drained.Has also had years of topping up with 803 and is rock hard.
I want to do a French drain around house and bring water through the compact section to the drain in front.

1)Is 3 inch yellow pipe ok for this?
2)What size stone?
3)Trench size? Depth?
4)The gutters run directly onto ground so can these be directed into French drain outlet?

Many thanks for your valued time.

Cousin of mine bought cottage just as you describe ( earth bank 1 foot down from window at back of house)
1 you'll have to remove all soil around house down 6 inches below floor level of inside house ( cousin put in new dpc insulation concrete screed inside)
2 i'd keep rainwater from gutters in separate solid pipes away from perforated pipe of French drain or the drainage stone will be always wet ( French drains work slowly draining ground even in dry periods)
3 if cottage has been rendered in cement ideally you'd remove it to bare stone or put on lime plaster
hopefully some ideas there but each has a cost