DPC level for patio

Czhornet

Hi all,

I am thinking about putting a patio outside our french doors for the summer. I am dead against timber decking, maintainance and slippy when wet are the main two reasons why its a non runner. The plan I am going for is a sandstone slab surface, laid on sharp sand on compacted hardcore. We want it flush with the bottom of the doors so that there is no big step for our toddler to be falling over. The problem is dampness. My understanding is the layer of DPC is laid on the top if the first block on the raft. This is the same level with the slab inside, but the finished floor is 150mm higher than the slab, therefore if the patio is flush with the door then the finished patio level will be 150mm above the DPC on the outer block. Will this cause rising damp?? or dampness inside. Is there anyway around this besides lowering the level or flashing/plastic between the wall the the patio?

sydthebeat

Czhornet wrote: »

Hi all,

I am thinking about putting a patio outside our french doors for the summer. I am dead against timber decking, maintainance and slippy when wet are the main two reasons why its a non runner. The plan I am going for is a sandstone slab surface, laid on sharp sand on compacted hardcore. We want it flush with the bottom of the doors so that there is no big step for our toddler to be falling over. The problem is dampness. My understanding is the layer of DPC is laid on the top if the first block on the raft. This is the same level with the slab inside, but the finished floor is 150mm higher than the slab, therefore if the patio is flush with the door then the finished patio level will be 150mm above the DPC on the outer block. Will this cause rising damp?? or dampness inside. Is there anyway around this besides lowering the level or flashing/plastic between the wall the the patio?

you need to get this construction detail designed. you cannot simply build up against a wall level with a floor.

BryanF

+1 on construction details requirements, indicating DPM and ideally ACO drain between door and patio

4Sticks

OP your toddler will grow up and will learn to cope with steps. Don't risk certain dampness.