Fixing wall plate to external wall

[strawberryzoe]

Hello!

I would like to fix my roof wall plate on an extension I am building to the external cavity of my blockwork wall rather than the internal. Both skins are blockwork with the inner using 3.5N/mm2 blocks and the outer 7N/mm2.

The reason I'd like to do this is that I am reroofing my existing house (1840s cottage with solid (ish) stone walls) and the original wall plate beared on the outer edge of the wall. The front face of both walls are in line and it seems silly not to match this position and have to build up on the inner course of the blockwork then place the wall plate higher up to match.

As a result of this, I would not be able to restrain the wall plate in the extension using the standard bent bar fixed to the inner face of the inner skin so would use vertical twist ties fixed to the joists instead which is a detail I have seen used before.

Does this make sense or am I missing a trick here?

Any help gratefully appreciated!

Thanks,
Zoe

 

[noseall]

It may be possible to fix a wall plate to the internal wall, lay the ceiling joists onto this plate then fix another plate to the top of the joists, then birds mouth the rafters to this higher plate.


This will insure the ceilings are level and get around holding down issues.

 

[^woody^]

Yes, strap the rafters.

The strap holds the rafter, the rafter holds the plate

However, I doubt your 1840s plate was strapped, nor any of the roofs upto the 1970s, and you don't tend to see lots of roofs lying in the road after a windy night

 

[strawberryzoe]

Many thanks for both your responses.

I forgot to say that the roof is a raised tie construction with exposed rafters so we have no ceiling joists and will have to be clever to hide the vertical joist ties!!

Oh the fun....