The Brew Cabin

Hi tony hope all is well with u you, i am after some advise and hope u have some words of wisdom, i am currently working on a job about 100 sqm, however 90 of that is on a steep slope towards the house and the last 10ish sqm's is flat by the front door and a garage at the side of the property, now we dug the job out and found a sub grade of very hard clay but reasonably dry so we put in the 150mm of Type 1 and roughly spread it around before going home for the nite then tuesday nite it pished it down solid for about 10 hrs we got on to the job wednesday and found at the bottom of the slope at the apex of the house where we were going to put the atco gulley drains in was full of water like a small stream and all the way up to the garage was also sodden under foot we then discovered that a roof gully had been leaking all over the job all nite long we emptied approx 100 buckets off the job, dug out some sodden roadstone and got the drains mortared in place however they are not going to function until the pavers go down which prolly wont be till friday or even monday but the wierd thing is every time we get the water off the job it just seems to reappear, and the area in front of the garage is still sodden, what is the best way to dry out the subbase so we can whacker it and screed and lay?? , another wierd thing is there is a work pit in the garage which we found out today is full of water:( so we again took out around 50 buckets of water until it was empty however we then noticed water coming in through the side wall of the pit literally filling it back up, well at this point it was getting dark and time to leave so god only knows what tommorrow brings i can only think we will uncover some sort of sleeping dragon that will eat me and all my workers :) it wouldnt suprise me at this point , do u think that a bilge pump would draw water out of the readstone?? the trouble is the clay i feel it just holds the water and wont let it dry out and stays as wet as a clowns pie:(

(Edited by suki at 8:17 am on Nov. 27, 2003)

As you're at the bottom of a slope, you'll just find that water keeps accumulating there for as long as the ground is open. In reality, the groundwater has been there all the time, but has been finding its own escape until you provided a nice, easy place for it to lodge.

I think you need to build a sump, preferably at some point just outside the pavement or in a discreet corner, and then line it with Terram, backfill with clean (no fines) stone or old rubble, and connect it to the drainage system. This will act as a collection point for all the groundwater both during the construction and after the job is finished, and ensure that the sub-base and sub-grade don't become saturated over time.

Is it feasible? Without seeing the job, I can't be sure whether it's possible to do this or not.

More worrying is the water leaking into that inspection pit. Has the householder seen this, and, assuming thay have, have they said it's a known problem or is it summat that's just started?

I think, if I were them, I'd be looking at some way of sealing that pit, as it's always going to act as a sump, possibly negating the effect of the sump I've proposed above, unless it's sealed in some way.

well after digging out some really wet mot and replacing it with dry and the fact its been nice weather for the last 24 hrs means the job seems to be firming up :), i made the customer aware of the water pit and they said its always had water in it and has been like that for over 20yrs and said they beleive it to be a sping :p, well were gonna wacker and screed tomorrow and block as much as possible so we can get the drainage woking to some effect, but all being well the job will look a lot better friday evening, then just hope the rain holds for the weekend so we can finish early next week.

I had the same problem about this time last year.
The garage slab was always wet, due I thought to a defective membrane and after very little rain a stream would run past our front door.
When I excavated the site I found a broken surface water drain in front of the garage and and the other drain that was only 100mm below the surface didn't go anywhere.
To get over the winter I dug a sump and installed a submersable pump (30 quid from Makro)
After installing the new Tony designed drainage, the whole site including the garage slab has remained perfectly dry and my tools have stopped going rusty.
Our local water company suggested that as I was spending a lot of money on the drive, I should take the opportunity to replace the water main.
It maybe that when your drainage is installed the pit will dry as well.
Regards Steve