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Posted: Fri Jul 17, 2015 8:23 am
by CharLou
We've started to build our below ground garage/basement. The original plan was to include a land drain but now its in doubt if it will do any good.

The problem is that we've hit the water table so trying to take this water to a soak away will be futile.

The raft is protected by Grace Preprufe 300 and the walls will be protected by Grace Bituthene 4000.

If a land drain isn't required then is it also unnecessary to use gravel as a backfill ?

Any advice is appreciated.

Posted: Fri Jul 17, 2015 9:48 am
by Tony McC
The land drain is, as you say, futile, but the gravel backfill will still help minimise water retention against the sub-surface walls. It may be that you need a sump'n'pump solution to keep water levels reasonable, but you should be talking to an engineer familiar with the site.

Posted: Sat Jul 18, 2015 8:41 am
by seanandruby
Might.need to install a catchpit and pump system .

Posted: Mon Jul 20, 2015 4:38 pm
by CharLou
Thanks for the comments.

My engineer said a drain isn't necessary, but said it wouldn't hurt to add one as a precaution to give me a little piece of mind prior to the backfill. If the worst should happen we could easily add a catchpit. Although strictly speaking this is probably overkill.

Once again thanks.