The Brew Cabin

Posted: **Tue Mar 20, 2007 1:10 pm**

hi
our new house has drainage problems in the garden.
The builder dug up the whole garden down to the clay about 3 ft in depth. He then dug out a trench of about 500mm wide across the whole width of the garden and put gravel in it, about 4-6 inches. he then put tarram on that, more gravel, then a plastic drainage pipe, more gravel then sealed the tarram over it. he branched off of it with three more pipes going lenths ways and then folded the tarram over them. he then put about two foot of top soil over it and let it settle for a couple of weeks. then sand was spread over the top soil and a couple of weeks later the grass was laid.
the grass has now been down for about 2 weeks and water is lying on the top in various bits. what has gone wrong?

Posted: **Tue Mar 20, 2007 2:36 pm**

Nothing has necessarily gone wrong. It always takes a few weeks or months for a new land drain to start taking effect, even more so on new build properties (not sure if the house is new or just new-to-you).

Installing a land drain system causes massive changes in the pre-existing groundwater regime, that micro-channels and pathways that the groundwater would normally follow. Add to that all the upheaval endured by the soils, and it becomes apparent that immediate improvement is not always likely.

I'd give it 3 months, minimum, before pursuing it any further. I'm fairly sure that if you were to call back your man now, he'd say pretty much what I've written above, but probably not as eloquently, natch! :p

In all honesty, I wouldn't worry about it until the back end of the year. If we got to next Nov/Dec and the ground was still suffering from inundation, then I'd be having your man back and pummelling him for an explanation.

Posted: **Tue Mar 20, 2007 4:39 pm**

thanks tony for your quick response, its a new build and when we moved in the ground was a 1-2 ft deep mud bath. the builder removed all the wet mud right down to the clay soil and sloped the ground up slightly both sides of the drainage channel. the garden is approx 14m w x 15m d and the channel was dug about 7m from the house accross the width of the garden. a couple of branches of channel was dug out as well. as i said the top soil was then put in on top of the clay, about 2 - 3ft in depth. has the correct thing been done or could i do any more. i plan concreting an area of 25 square meters for a patio then slabing on top of that. do you think that this is ok.

The Brew Cabin

New build garden drainage - What now