Has anyone any experience of installing a drain de herrisson routier inside their house? We've excavated 30cm down to reinforce the foundations of our house on the north wall and discovered water!! Lovely surprise - not! It appears the earth behind the internal wall was hiding this delightful natural source...now besides bottling it and calling it Eau Fitzgerald the best solution seems to be a drain de herrisson and to evacuate the stuff. I've had the Geometre round today who did the sondage last year (where we dug down 5.4m and found no sign of water last August - yes ok it was Summer but we've hardly had any rain at all here in Herault this year). He has recommended a Drain Herisson Routier beneath the new dalle with a geotextile layer. I'm waiting for his report to send to the structural engineer to redo his drawings taking this into account as he also wants to amend the foundation depth as a result of this discovery.
Just wondered if anyone else has installed one or has one in their house and how well does it work? Would you have done anything differently?
Cheers
ok photo above of drain going in…it’s a drain routier so flat at the bottom - then it has grains de riz (very small gravel) on top. Immediately after the trench was dug and the drain went in the water drained and today the soil was drying out nicely, helped by the lovely weather this weekend. It looks like it might not be a spring because the water increased with a very high downpour last week and has now slowed and is drying out.
Here's a diagram.. of how it might look when finished. Supposed to be excellent at keeping out humidity in future.
We’ve investigated the other side of the wall which is a hidden passageway under next doors kitchen (originally the 2 houses were independent but in exchange for our right of access by vehicle to our garden at the back via a chemin the previous owners gave up the passageway and they built above it to extend their upper living floor but left the beneath like it was frozen in time). That was a surprise to see a while back when we did our party wall visit with the huissier but it did mean when we saw the little water trickle I asked if we could have a look on the other side of our wall.
What we found was totally dry wall, totally dry earth at surface level so we were then looking for a leak somewhere...turns out neighbour has a well in his front garden. We investigated but the water level is 6m40 down and our foundations with water trickle is only half that so it can't be the well. Also when we did our sondage last year the water level was 5m40 below our floor. We've only dug out 50cm so we should be nowhere near the nappe - water level.
Only other thing we can think of is hidden water pocket or vein which has been released as we've removed the compacted earth or possibly rainwater from road which is sinking into soil below the road level and then finding its way down to our RDC ground level. As I say next door was completely dry so the problem is 3m below the road level but at least 3m above the level of the water in our neighbours well (which was beautifully built in circular stone fashion - scary as hell to look down as its in the floor and once he removed the grid was basically a long long way down!)
At least we know its there though and can use it to keep an eye on the water level. I'm also now investigating more into the history of the houses to try to find out more about them...it is really interesting to see why they were built the way they are.
Although one man told me that the ruisseau just down the end of our garden once used to go up to the height of the bridge 50 years ago...now that is not news I wanted to hear!
Not heard of it Suzanne but it will be something you need to bare in mind when you consider having a pool in the future.
Well it is quite weird as it was completely dry before, the geo expert says it could be that there are pockets of water escaping and that it could easily dry up but better to put the drain in. Its not pouring more gently trickling. Hopefully the hedgehog drain will sort it out. We have a couple of months before we close it up to sort it out...fingers crossed.
A useful guide here.
http://www.alliance4.fr/uploads/fiches/documents/herisson_de_pierre...
I don't have one but reading this I'm not sure how well it would cope with flowing water as opposed to a high humidity content. I know that in the UK similar arrangements were not uncommon in buildilngs built before the introduction of the damp proof course of impermeable Staffordshire brick.
If there's a lot of water you might have to consider a sump and pump.
An intercepting drain built round the property would also help the situation.
PS Has the water company got a leaking main?
