French drain?

[jacko555]

House is on a slope.

North side higher.

I've dug out the weeds and found, what I think, is a French drain running along the north side.

Previous owners had planters on stands here, so not growing in the drain. However, house has been empty for a few years (and the owners too infirm to manage for a few years before)

It looks to be filled with pea shingle and compost natuarally formed. It took a few hours to pull out the naturally seeded weeds and flowers there.

I have no experience with french drains, if indeed it is one.

Is it?

If so, should I dig out the mud and pea single and replace with larger stones? (I've read that advice on this forum)

Any tips?

 

[KenGMac]

jacko555, good evening.

Can I suggest some investigations? this is the only way you will find out if this is a french drain.

if you can? do a careful vertical excavation into this gravel area, what you are looking for are depth of gravel, or indeed stones, pebbles Etc, any small diameter "rock"

At the same time a judgment call needs to be made? that is an appreciation of the volume of mud / muck that has permeated into the gravel layers.

Generally, but not all the time?? there may be a perforated drain or [old school] clay sections of "D" shaped pipes in short lengths, of about 300.mm [one Foot] these clay sections are not connected the gaps between the sections allow any water gathered in the gravel to get into a pipe or a section of pipe.

As noted above the clay "D" section clay ware is laid with the flat of the "D" laid on the base of the trench, or better still on to a gradient of gravel.

Can I also suggest you have a look in any manhole close to this area, either front or rear for a connection that may??? be a drain outlet to this "French Drain??"

Finally, what type of soil do you have in your area?

Ken.

 

[jacko555]

Hi Ken,

Thank you for your advice.

On the western side the sewer runs north/south, and passes about 2ft from the end of the trench / french drain. Its possible it drains into that.

The corner on the far eastern side is the dining room, has signs of blown plaster and a damp musty smell internally. If indeed it drains into the sewer, the eastern corner is fartherst away from the sewer. It could explain things. However, the house has been vacant for several years, and, downstairs was not inhabited for seveal years before that (when previous occupant was too infirm) so it could just be a musty smell.

The external wall also has green algea after I removed the mass of plants growing against it / behind the planters.

I shall endeavour to excavate a few areas and report back findings. As it stands, its just a gravel rich flowerbed resting against the foundations, which cannot be good. House is 100yr old, with a very narrow gap cavity wall, with original lime plaster / fairly original internally.

In terms of clay D sections, I have found 8 large D sections neatly stacked in a corner of an overgrown headge. I assumed they were roof ridge tiles. They are v.old but unbroken. The roof is original, and, intact / has all the ridge tiles present. Perhaps they are leftovers from the drain?

I'm on the south coast so very chalky soil.