How do I attach a joist parallel to the wall below the DPC?

[dent]

Hi all,

I am building a suspended timber floor for my new extension and I need to fit a small stringer joist to work around a step in the wall. The joist will be parallel to the wall, and below the DPC. If I attach it directly to the wall it risks getting damp and rotting. Is it sufficient to pack the joist out from the wall with some stainless washers to provide airflow, and if so, by how much? Should I put some DPC between the timber and the wall as well?

thanks,

dan.

[The Medway Handyman]

Kinda the reverse of fitting a deck joist to an external wall. I pack out by 10mm with washers. Use Tanalised timber & treat the end grain - it should never rot.

[Phil L]

I'd be very surprised if a BCO allows this. Can't you use steel?

[dent]

You were right. The BCO didn't like this and has asked me to use a multi-truss hanger and a small sleeper wall instead.

thanks,

dan.