DPC bending the rules

[71-1093879279]

Hi Tony, I'm dealing with a client at the moment who wants to raise the height of his existing patio to reduce the step from his back door. I've read through your notes on DPC and bending the rules and have a couple of supplementary questions.
If I go for the Dry area arrangement, is there a minimum width for the channel? Could the channel be capped with a grill and if so does the grill have to be kept below the height of the DPC?
I know you are not keen on decks but if I was to suggest one as an alternative, would I still have the same problem. ie If I put a Ledger board on the building to support the deck, how close to the DPC could I attach it?
Thanks in anticipation Ian.

[84-1093879891]

There is no stipulated minimum width for a Dry Area Channel, but I'd say 100mm would be a reasonable minimum. If you wanted to cap it with a grating, then that's fine - you could make it simpler by using a length or two of linear drain. As long as the top of the linear drain or grating is at or below dpc, then it's fine.

The same applies to using <spit> decking. The top of the deck needs to be at or below dpc level.

There are some workarounds for situations where you need to breach dpc. These are outlined in a supllementary publication to Document M of the Building regs and are intended for use with disabled access doorways and the like. It's called "Acessible thresholds in new housing", and, as the name suggests, it is aimed primarily at ne3-build properties but the workarounds detailed therein can be applied to existing properties. They have the effect of bring the exterior paving level flush (or just a few mm below) internal floor level, or the access cill.

The exact detail varies with the type of paving involved.

[71-1093879279]

Thanks Tony, I've got another job in the pipeline where I need to sort out wheelchair access so i'll take a look at the building regs you mention, cheers Ian.