French drain or not?

[Triassic]

I’m about to lay patio slabs and was considering whether to simple butt them up against the exterior wall, or to leave a 100mm gap and install a French, decorative pebble filled, drain, or to fit a plastic kerb drain? What our you suggest?

[Dave Jones]

as long as they are a min of 150 below your dpc and sloping away from the building you can butt them up

[Triassic]

2 hours ago, Dave Jones said:

as long as they are a min of 150 below your dpc and sloping away from the building you can butt them up

So, if it’s a flush threshold you’d advocate a drainage system? If so, what type?

[Temp]

The reason the dpc should be 150mm above patio is to prevent rain splashing up above DPC. That may not matter at a threshold because the rain splashes onto a door or glass etc. 

 

Thus is what Building Regs recommend for a level access threshold..