French Drain Advice

[Zebra]

It depends and may be very much a matter for judgement on site. If there are no foundations, obviously you don't want to undermine the wall and create a structural weakness. Getting the ground outside the wall to slope the other way to take water away from the house would seem like an obvious better solution before you start digging adjacent to the wall itself. I would think (although my experience is limited, but I did create a French drain that didn't work...) that if your foundations are as minimal as you say, then the further from the house the better. If you are only trying to redirect surface rainwater run-off, if it is normally OK except when there is exceptionally wet weather such as we have had recently, I would imagine that caution is on order rather than dig some drastic channel which might do structural damage to the house.
The rule, as I understand it, is not to dig within the zone under a 45 degree angle from the bottom of the foundations. That is, if you drew a line downwards and outwards from the lowest part of your foundations (does that make sense? perhaps I'm not explaining it very well) then you mustn't disturb that ground, so that your foundations are not undermined.
If you can get the ground close to the house to slope away from it, and dig a channel further away, and of a depth that it doesn't come close to the area in the 45 degree zone (I must try to find a way to explain this better....) and have the drain pipe in it actually drain to somewhere, ie a soakaway or drainage system, then it seems like it would be a good idea.
I started a thread on French drains some time ago, where people were kind enough to give me some very useful advice, so here's a link to it: http://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=12190

 

[LadyArowana]

Do the French refer to them as "French" drains or are they just "drains" there? Their building products certainly manage to sound interesting, even when the picture is a plastic pipe wrapped in something, it sounds better as "Accessoires récupérateurs eaux de pluie".

 

[Gervase]

For once the naming was't an attempt to smear the Froggies they were named after an engineer called French.

 

[LadyArowana]

For once the naming was't an attempt to smear the Froggies they were named after an engineer called French.

Thanks, that's interesting, I hadn't even thought of that possibility.

 

[Lime]

I would not be digging any trenches next to the house.
The problem as I see it is that the road/path surface has been added to over the years.
(This is a very, very common problem.)
As a consequence of the raised road/path and the wish not to bury the house (!) a gully has inevitable been created that channels water next to the house as it runs down the slope.

I suggest two things:
Lower the entire road/path surface so that water is taken down the slope and not directed towards the house.
Install a drain or extend the downpipe (shown in pic) to take the rain water well away from the house.

 

[Lime]

I would not be digging any trenches next to the house.
.........................................................
Lower the entire road/path surface so that water is taken down the slope and not directed towards the house.
Install a drain or extend the downpipe (shown in pic) to take the rain water well away from the house.

How can I install a drain if I don't create a trench (however small) next to the house?

Regards

Alex

?
A trench does not have to be dug if some form of piping is connected to the down pipe.
From the photo it appears the downpipe is at the lower end of the slope.

Any trench dug to fit underground piping or culvert would be from the corner and away from the house.
The trench would be next to the house wall in a very small area only and would then be backfilled with solid material, unlike a french drain.

The suggestions I made were not either/or, both need to be done.

 

[Lime]

I appreciate you do not think the water from the downpipe that important but I'm thinking of the general water content/water table in the soil around the house.
The more water you can prevent actually entering the soil the less of a damp problem you will have.
The water flowing on the surface is demonstrating to you that the immediate subsoil is likely to be saturated.

 

[worms]

For once the naming was't an attempt to smear the Froggies they were named after an engineer called French.

Thanks, that's interesting, I hadn't even thought of that possibility.

Interesting indeed! A "Period Property"* I visited recently appeared to have what I would have described as a French drain below its rubble construction wall, despite it pre-dating Mr French by a minimum of 300 years and possibly up to 2,000 years! But I see from Wikipedia that Henry French actually added a clay roofing tile to the construction which would be a big step forward.

*Probably iron age