I’ve a wall in an 1800 house, semi basement 9” brick, at some point in the past the original wood floor was removed and filled with concrete and the walls “tanked” externally the pointing has been redone in sand and cement. The wall is pretty much saturated and damp penetrates around the windows and points where the tanking has failed / was done poorly.
Pulling up the floor and redoing it, removing the tanking are neither economical or practical.
Its been suggested a french drain along the wall will at least prevent the wall getting any wetter and repointing with lime will help the wall dry out a little over time.

Plan is for a 600mm wide trench along the wall to 100mm below the concrete floor level, a studded dpm against the wall , a geotextile in the trench then backfilled , suggestion is to use cockle shells ( available locally) as this will give plenty of air space and quick drainage.

The wall will then be repointed in lime.

The homeowner understands that this will not make any immediate improvement , but that it should prevent further water being sucked into the wall and over time allow the wall to dry out a bit.

Is this a sensible way forward? Being a diy project its not overly expensive . Any suggestions to improve or new ideas?

TIA

For me 150 wise 300 deep bottom 75mm filled with beech pebbles repoint in lime

Posted By: Artigliothe rear the kitchen opens onto the garden

sounds like you have a walk-out basement, then.

(like me)

gg

https://youtu.be/bEVBOEIktr4
Usefully better than many other resources I've frittered time away on
Recommended for French drain detailing

@artiglio what did you do in the end and was it successful?

I am looking at a similar sort of situation and trying to work out the options.

I've seen some advice that it can be a bad idea to install a "French drain" right next to a wall for risk of destabilising the foundations, especially if they are shallow. We suspect the foundations are shallow, and it's a clay soil area.

Because of the location (a small urban front garden) it's difficult to connect any drain either to a soakaway or the public sewer. I've been wondering if a gravel-filled trench (but without a pipe at the bottom) is better (or worse!) than nothing. Because the outside ground level and inside floor level are at much the same height, if any water close to the wall could at least be encouraged to sit (and gradually soak away) say 150mm below ground level, instead of at ground level, then less of it might make its way through the lower portion of the wall to the interior.

Can anyone recommend any good technical resources for this kind of thing?

Good day lineweight,

As yet nothing has been done, however the householder has been persuaded that heating the house a bit more , using the extractor fan in the kitchen and a bit of localised removal of the cement pointing ( little more than a smear in most places) might give an indication of how bad things are.
The result has been a visible improvement in the extent of the “ wet looking “ brickwork , the plan is to keep the changes going over this summer and monitor what happens and then have a rethink on what may or maynot be the best way forward.
Basically hoping that over the drier months the walls keep drying out slowly and so convince the homeowner that keeping the house a bit warmer is worth the expense and that next winter with slghtly drier walls the cost of the extra warmth is reduced a bit.