Damp Proof Course & Patio

deepdown

I had a single storey kitchen extension built a few years ago. It was all signed off by building control, however the grass was left right up to the building and since covid happened, it was a year or so until I could have the garden landscaped. 

The landscaping was done by another company. When they took up the grass, they discovered the builder hadn’t put the drainage pipes and system low enough, in order to leave 15cm below the airbricks when a patio was built. 

By this point the works were paid for and the patio stones ready to go. The landscapers told me the best thing to do was to build a French drain around the brick and not too worry too much about it. It’s mainly under a bifold door. 

I have no internal signs of damp in the house. But with winter wet weather coming I’m more worried now about it. The bricks are damp below the gravel ‘drain’ and I’m wondering if it’s better to take out the stone and sand in this ‘French drain’ and let them air dry? Or if this will simply expose them to more rain? 

I’m really unsure of the best thing to do…will this cause me major problems if I try to sell? Photos are attached. Thanks for any advice!

stuart45

I wouldn't be too worried about that. Is it a block and bean floor?

canaldumidi

You mention sand. If you've got sand in there, take it out as it will hold water and make the wall damp (albeit still below the air bricks. It's not clear where the dpc is though. The point of filling the gap with stones (& slate by the looks?) is that water will drain down round the stones so any dampness will be much lower down.