Monty was surprised! He made an off-camera remark after we first did the drainage test and he said that the best thing would be to remove it all. He wasn’t expecting us to do that. We didn't think the solution would be so extreme.
As it was a new build, we were fortunate to have a one-year snagging list whereby our developer would sort out problems with the build. After initially taking off the turf and a thin veil of top soil, we hit compacted clay sitting on top of the rest of the soil. Below ground was a 2 metre long sack of large rocks – the soakaway. Our developer had his experts come in and assess the clay, the size of the soakaway and our drainage pit finding. It was clear that it wasn’t up to scratch. As we’re at the bottom of a slope the rain water from the surrounding homes was coming in through our garden with little chance of escape and submerging the lawn by 1-2 inches over winter.
Six weeks later, 60 tons of soil was excavated and a huge water holding cage sunk into the ground. This was covered with landscape fabric, gravel and more landscape fabric. The new drainage systems also had new pipes installed so that it could overflow into the surface water drains.
Of course, with all the soil and clay gone we needed to replace the top soil. The developer paid for most of it, but it wasn’t enough to fill the garden. It came to 31 tons in the end, with another few tons of compost and bark chips on top. It had to be done. And we had to pick up part of the unexpected bill.