Sorry if this is in the wrong section, I have recently moved into a new build house with some rear drainage issues. After any moderate rainfall, water collects on the patio outside our back door and against the wall in the gravel boundary. It takes days for it to clear away. The back lawn slopes towards the house and is on top of very heavy clay soil which is causing this. The water is a good 10cm below the damp proof course
The builders are coming back to inspect a land drain which is at the bottom of my lawn to check it is working correctly but I don't think this will be sufficient. I'm trying to put the onus on them, as once I get any other contractor to start digging they will say the NHBC warranty is void.
Is there any risk of damage to the walls or foundation if the pooling of water is allowed to continue for a long time? Are there any solutions I should be pushing for them to implement in this scenario?
Thanks for any help/advice
