The house below was built on sand at the bottom of a sloping lawn. The 12 feet wide patio stretching the length of the back of the house was laid on top of 2 feet thick of blue clay. The lawn sloped down towards the house and also sloped towards the hedge you can see on the right hand side. When it rained, the water would flow off the lawn onto the patio and then to the house. The water then percolated down to the clay, which then swelled (clay can usually absorb 40% of its own volume in water before it turns from a solid to a liquid) which caused a break in the wall above the bay window, resulting in subsidence to the building 6 years after it was built.

Looking round the back garden in a clockwise direction.

These houses were built in an existing pine forest.

So I had the soil analysed to see how fertile it was. In taking the soil samples, I discovered that the areas that I took the soil samples from were sandy rather than clay.

When I took up some slabs by the house, I discovered that there was clay underneath them.

I produced the following current design followed by the proposed structural design:-

The above structural design would then produce the requested requirements.

I dug a spade wide trench and 3 feet deep along the outside wall of the dining room and kitchen to discover that the clay was 2 feet thick. I lined the trench with Plantex membrane (available from Travis Perkins) and filled it with Type I MOT Roadstone from Allsand Supplies. The Plantex stops the Roadstone from mixing with the clay and sand surrounding it and the Roadstone will drain any water to the sand below without heave or subsidence.

I suggested that the foundations for the conservatory wall should be of solid concrete at least 1 foot into the sand under the blue clay:-

6 cubic yards of concrete were used to create these conservatory wall foundations.The soil within this concrete could then dry out and it would then not get wet from rain and therefore not swell or shrink.

The Kompo Mulch and Organic Manure were stacked under the pine trees in the Woodland Border before being mixed with the transferred soil on the levelled lawn. The trunks of the pines swelled so much in 2 weeks that the bark split. This was due to the fact that the nutrients in that mulch were started to be used by the pine trees which had been starved of any nutrients for years.

The new Path/Patio at the back of the house was then sloped away from the house and the rain drained to the Gully, thence to the Sump in the middle of the garden.

The levelled lawn then needed a Patio wall to stop the earth from being unsurported.

Levelled lawn in both directions, with the conservatory/path areas sloping away from the house to allow rainwater to be collected and taken to the sump, instead of causing further damage to the house.

Proposed Garden Water plan

Proposed Garden Electricity Plan

Proposed re-use of old patio slabs to reduce costs, instead of buying new Marshalls ones as shown in a previous plan.

THE DAMAGE CAUSED TO THIS HOUSE WAS DUE TO THE BUILDER USING CLAY INSTEAD OF SAND NEXT TO THE HOUSE, WHICH STUCK TO THE EXTERNAL HOUSE WALL AND PUSHED IT UP AND DOWN ACCORDING TO HOW WET OR DRY IT BECAME. ALSO, THE BUILDER HAD SLOPED THE PATIO TOWARDS THE HOUSE INSTEAD OF AWAY FROM IT.

ANY HARDSTANDING NEXT TO A BUILDING SHOULD SLOPE AWAY FROM IT OR HAVE DRAINAGE BY THE HOUSE TO TAKE THE WATER AWAY. IF THE WATER IS REMOVED TO A SUMP, THEN MAKE SURE THAT THAT SUMP IS NOT IN CLAY SOIL. IF SO, WATER ENTERING IT WILL NOT DRAIN AWAY.