I've spoken to various contractors but none have really filled me with confidence about the new patio I wish to lay so I thought I'd ask you clever people on the internet.
I've had two sets of bi-fold doors installed and want to lay the patio as close as possible to the height of the door sills. Unfortunately, this is about 10-12cm above the DPC. This picture might help:
The DPC is just below the bell bead. The bricks below that have been injected with "stuff" and coated with vandex. That area of the house has had problems with damp in the past although it has recently been stripped back to the bare bones and should now be sound. I'm nervous about breaching the DPC and would like to avoid using pea shingle as I know it's going to be a magnet for fag ends and the like.
If necessary I could take off the bottom 10-12cm of the render on the LHS of the door (this has already been done on the RHS of the bi-fold doors). But what would you suggest then? Some kind of drain?
this detail seems all the rage now
ideally the existing wall would have a damp tray installed and then you would have a linear drain along the door
the patio needs to fall away at around 1:50
all new builds tend to have this built in,but its much harder to make it work in an older house
the dpc you are looking at is the dpc that your 4 by 2 floor joists sit on
very common in older houses
so you need say flag retainer 100mm away from the wall,and where the doors are a linear drain
a french drain is not a good solution
something like this
cheers LLL