The Brew Cabin

Hi Tony,
drove past a previous job today - it was raining heavily so couldn't think of many other things to do - and noticed a small pocket of water retention. The job is a driveway of around 2.5m wide x 20m long, done in Brett's 3 size rumbled alpha.
When we started this job I noticed the drive was almost flat but as there was no other easy way around it I set it out to fall the water to the pavement, with a slight twist towards the lawn after the end of the bungalow. I don't suppose the owners are too bothered, but what do you suggest to prevent this happening in future? The fall on these blocks is at a guess 4" over 20m , a lot less than your recommended minimum of 1" over 2 metres.

Thanks, Richard.

The simple answer is to increase the fall. 100mm in 20m is a scary 1 in 200, which is, as you note, well below what I would normally suggest.

Although you can get away with ridiculously tight falls with a well-laid block driveway, if you get a few mil of settlement in 2 or 3 years time, it can result in what looks like a big pond, but is actually only a rizla-thin sheen of water. Still, the property owners are on the 'phone and other passers-by have spotted your "lake". :(

When we come up against this sort of tight fall, I always err on the side of caution and bang in an extra gully or a length of linear drain, and then set out the falls to direct the water to these new drain points, along with the existing gullies, the public footpath, garden etc.

It may put your overall job price up by a few quid, but I always found the better clients were more than happy to pay for an extra gully if it meant they had a well-drained drive that would give them many years of trouble free service. I'd rather do that than take the risk of having to be called back to install a gully 12 months later, often at your own expense.

So, try to keep falls to 1:80 minimum, and if that's not possible, look to install additional drainage so that the min fall can be achieved. :)

Hi Tony,

thanks for that. Drove by again today and knocked the door, explained that guilt had got the better of me and would come to repair the dip as soon as the weather was dry. Old folks made me some tea and seemed quite bewildered !
Like you say though, it's what the neighbours and passers- by think as well as the customer.

Ta, I'll survey it better next time !