Poor drainage can be a real issue for many people, and we recently had a client experiencing a lot of issues on his property. When water goes to the surface it can create a wide range of problems, from pooling to erosion and more.
On one particular occasion, one of our clients had a patio with slabs and sharp sand, which meant the water pooled in one corner and constantly ate away until the patio subsided. There was also a wall attached to this that, part of his house, and if it had been left there for long enough it would have subsided. You simply can’t avoid subsidence if there is water corrosion in that area. His drain was there, but it was filled up with loads of gunk.
At first, we tried a standard soakaway. A soakaway is a pit, typically filled with hard core, into which waste water is piped so that it drains slowly out into the surrounding soil. Our plan was to create a soak away 1m x 1m, and approximately two metres deep. However, his area of land was set on a chalk shelf, which limited the soil’s infiltration rate; as soon as you hit chalk, water fails to penetrate – you might as well have a goldfish bowl!
So, instead, for guidance, we contacted the guy who designs the soakaway crates. He suggested we make it longer and wider, and that we should bring it up to the minimum you can get above the crates. We did another trial hole and another infiltration rate. The rate was based on coming above the chalk shelf using only a minimal amount of soil, which was left above the chalk shelf to try and spread the water out, in any direction we could.
We managed to achieve a satisfactory infiltration rate using a very shallow soakaway at 3.5m x 3m.
Furthermore, our client also has planning permission for a planned extension, so we took all the roof space from what might be leading in to the back garden for its drainage and future proofed it so he never has to worry about it again.
Another company told our client would do a hard floor soakaway without an infiltration rate. That means they would have simply dug a hole, filled it, run some pipes and that’s it… cover it over. We did a thorough job, with a sheet telling the infiltration rate to show the building inspection agency that you’ve done it properly.
At the same time, we also made some adjustments to his drains at the front. He actually had aluminium seamless guttering fitted to his house, meaning everything was seamless and in one piece… I have no idea how they fitted it! But it looks amazing and, more importantly, it works.
So, after that he’d relocated the outlets and redirected some of the water to different areas, the pick up points needed to be moved at the front and back, which we did by using modern bottle traps with old school crates. His house is basically an old stable block, so the pick up points would rely on clay bottle traps with metal crates, which can be weak. They don’t take a good hit and if there’s a weak link they’ll crack, and if they crack they’re not doing their job properly. We use modern bottle traps, and I actually bought some metal crates off eBay, which look really cool and old school, and they just fit in the hole… and futureproof his house in the process.
If you would like to discuss any drainage issues with us, please contact us on the details at the bottom of the website.