Neighbour's garden height

[Anonymous]

Been perusing th PP website for some time now, and have gained some great help so far, but I am hoping for some advice on a particular problem...

We recently purchased an old farm cottage in Somerset, and the neighbour's garden is about 3 feet higher than ours. We are separated by a stone wall approx 1" thick. In itself this is no problem, as their garden is not affecting the main building. However, previous to our ownership, sombody built an extension onto the end of the property, and we are experiencing problems of damp in this extension wall, along the side that backs onto the neightbour's garden.

My question is this... Would a french drain be a suitable way to alleviate the damp problem? Or can anybody suggest an alternative? The neighbour is perfectly happy for us to excavate a drain of some sorts, but obviously re-landscaping their garden is a bit impractical!

Hope somebody has some ideas...

 

[Anonymous]

Your one-inch thick stone wall sounds an interesting structure! <IMG SRC="http://www.periodproperty.co.uk/discussing/smileys/wink.gif" BORDER=0 ALT=""> Typing gremlins, I presume?!

I assume that the damp wall of your extension is actually in contact with the higher soil level of your neighbour's garden? If so, then this certainly sounds like the reason for the damp.

A trench or french drain would definitely be my first choice for solving the problem. Try to get it as deep as you reasonably can, but be sure that you don't get down as far as the bottom of the foundation. If the trench ends up well below your neighbour's garden level, you may have to build some kind of retaining wall to make sure their garden soil doesn't start collapsing into the trench.

Don't expect the damp wall to dry out quickly - particularly if it's very damp and has been in that condition for a long time. You can help the drying out process by hacking any plaster off the internal face of the wall (and the exterior, if it's rendered), up to just above the height of the damp. Leave it like that for a good while, to dry out thoroughly. Now would be a good time to do this, so that the summer weather can help the process.

 

[Anonymous]

Ooops! And to think I proof-read it too!

Thanks for your response.

The wall is not plastered internally, nor rendered externally, so little work to do there. My plan was to dig a trench in the neighbours property, line it with builders groundsheeting to prevent soil/other particles clogging it in the future. Then I plan to backfill with decreasing grades of gravel/stone. The convenient part is that the neighbour is reworking that section of the garden, and intends to use the area where the trench will be as a path, so she is not concerned about me backfilling entirely with stone.

Unfortunately, I will not be able to build a retaining wall to maintain a space between the wall and the ground level. Do you think this will render the whole drain pointless?

Many thanks for your advice!

Rick

 

[Anonymous]

The lack of a retaining wall won't in itself render the trench pointless. However, it does increase the risk of soil crumbling into it, if the trench is particularly deep. However, your backfill with stones should help to reduce that risk.
I presume you won't be putting your groundsheeting up against the damp wall? That would definitely reduce the possibility of it drying out effectively. If possible, I would also try to leave the trench open for as long as you can before backfilling with stone/aggregate/etc. The more air movement you can get against the damp wall the better.