Joist hanger angle tollerances

[i_am_fubar]

I am planning on hanging my extension roof joists from 270/91 jiffy hangers:

http://www.fix8.co.uk/products/Hang...ong-Tie+JHA270/91+91mm+Jiffy+Joist/1899047913

I know these aren't suitable to hang pitched timbers from, however in a flat roof, are they able to take up the fall? 1/80 is only 0.72 degrees, but I can't find tolerance figures anywhere.

Only reason for asking is on the chance we can get away with not having to mess around with cutting furrings and accept the pitched ceiling inside.

Cheers,
Fubar.

 

[tony1851]

Less than 1 deg. won't make any difference to the support on the bottom of the hanger.

 

[big-all]

are you happy with the ceiling sloping ??

 

[i_am_fubar]

Cheers Tony,

And Big, it's one of those things that if it was properly sloping, then it would be a feature. But 1 degree out could look pants, especially if there is a detail of any sort.

Biggest problem is making sure the wall plates match the slope for the fascia ladders.

The joists will be doubled up 150x47's, and I would rather have the deck sitting on the 90 odd mm wide bit of timber. So I would need 90mm firings on top.

We're not planning on closing up the underside for some time, so I can always put thinner firings underneath and fit plaster board to them to get a level ceiling. Or reducing height batons.

Fubar.

 

[big-all]

fair enough

hows about bottom timber level top at 1 degree and firings/timber every foot filling the gap as required

 

[i_am_fubar]

I think I know what you mean. So instead of having to cut tapers, just use ever reducing thickness of baton perpendicular to the joists. Was thinking about that last night.

Just need to make sure I can still fit the drop down projector, screen and disco ball

Fubar.

 

[big-all]

if you want them to look neater and be stronger you could use 6 or 12mm ply to each side glues and screwed