The Brew Cabin

Further to my driveway post.... ;o)
The site we are buying slopes approx 1:20 with clay approx 1' below the topsoil, subsequently there is a fair flow of water down the hill which is busy washing away the lime moratr and non-existent foundations in our barn. A geologist has suggested putting a1.2m deepx80cm French drain consisting of stone backfill and running the French drain down to a pond which would also take the treated water from a mini treatment works+reed bed. This seems fair enough to me any thoughts? ALso what type of stone constitutes backfill, and is there still a need for putting in the geo-membrane to keep the weeds out, or should I start a family to breed weeders as a cheaper alternative?

French Drains, in the true sense of the term, are so-o-o-o out-of-date! What you need is a properly constructed Interceptor or Collector Drain, as featured on the Land Drains page.

The stone fill needs to be an inert, clean gravel, ideally 5-20mm in size and a geo-mmembrane is essential if you want the drain to last as long as the house. Admittedly, starting a family is more fun than installing Land Drains, but, the trouble with breeding is that you're lumbered with spawn for the next God-Knows-How-Long, whereas, with a decent Collector drain, once it's installed, you don't have to worry about it again, and you don't have to give it money, teach it to drive in your beloved car, or bail it out of prison! :)

Cheers Tony,
Obviously you've never met our lass if you think starting a family is more fun than laying land drains ;o)
Glad to see you back anyway, and thanks for the speedy response. I had read the page already on the collector drains and was thinking of that kind of arrangement, but the idea of water staying in a perforated pipe seems a little strange to me...but if that is what you say then I have no reason to doubt you!! Although I will hunt you down if I have an indoor swimming pool come February!!!
Cheers,
Paul

It doesn't stay in the perforated pipe for long, though. It follows what is known as the "hydrostatic gradient", which means it'll hang around in the pipe when there's more water outside the pipe than inside, but, as soon as the water level on the outside falls, then it quits the pipe and rushes out to where the hyrdostatic pressure is less. :)

Tony,
A couple more dumb questions [:I]
The perforated pipe- should it be perforated all the way round, or just on one side? And if the latter, do I want the holes up or down?
Also, have you any recommendations for the type of membrane? Travis Perkins have about a zillion to choose from (well, ten or so!!)
We are actually getting cracking on the place tomorrow, so this time next year I might be able to make a decent cup of char [^]
Cheers in advance- one sugar or two?

It doesn't really matter whether you use a half-perforated pipe or a fully perforated pipe. Generally, I tend to spec half-perf pipes for dispersal systems and fully-perf pipes for collector systems, although some contractors and specifiers uses half-perf laid 'holes down' for dispersal, and 'holes up' for collector drains.

For small-scale applications, I've never been convinced of the argumnent to use half-perf pipes. There's no cost saving involved, and the fully perf pipes are easier to get hold of, so that's the way I usually go.

For membranes, you can't get yourself bogged down (no pun intended) in checking out tensile and shear strengths, O90 pore sizes and all sorts of other technical mumbo-jumbo, when a simple, straightfoward option is to go for the Terram 1000 or its clone, the TDP115. They are good all-rounders, rather than specialists, and there's no real saving by switching to a lower spec, such as a Terram 700. And again, the T1000 or the TDP115 are generally available 'off the shelf' in manageable quantities, so you can buy a 50m² handy-pack rather than a 2,2500m² roll of the stuff.

So, when you do get the kettle to boil, no sugar and just a dash of milk for me, plrease. :)

Splendid, I'll get myself off to the merchants then! Got to spend this mortgage thing somehow :o(
Consider the kettle well and truly on, or at least it will be when Northern Electric (or whatever they are calling themselves this week) get their act together!
Will no doubt be in touch soon. Thanks again for the advice!