Fit joists inside wall as opposed to on top of wall plate

[aztectt2000]

Long time forum lurker looking for advice.

I've had a brick workshop built up to the wall plate in the garden. I need to keep it below 2.5m overall to avoid planning but have hit an issue when it comes to the flat roof construction.

Because the span of the roof joists is 6m I've gone for 9"x2" joists (bought and ready to fit) on the advice of various span charts. The problem is that sitting the 9x2's on the wall plate as originally planned will make the building too high. So I've been looking at cutting an L shape out of each end and sitting them on joist hangers which will be bolted to the wooden wall plate. Assuming there is enough ceiling height inside the workshop, is this acceptable?

Also could I buy two different size joist hangers to create a fall from front to back? This would mean I don't need to fit furring strips.

Thanks.

 

[noseall]

If height is an issue why not lower the plate?

or.....

Is it critical that you have a certain ceiling height?

 

[^woody^]

If you notch joists, they become as effective as a smaller section joist ie minus the notch

Put them on hangers ........ or lower the plate - however you don't need a plate for flat roofs

 

[noseall]

- however you don't need a plate for flat roofs

Yes, but you may as well put one in and make (holding down) strapping easier.

 

[RonnyRaygun]

If you notch joists, they become as effective as a smaller section joist ie minus the notch

Put them on hangers ........ or lower the plate - however you don't need a plate for flat roofs

Although, if notching at the end of the joist, you will only reduce the shear capacity, which is usually not an issue anyway.

If you want to notch the joists, I can tell you the maximum depth, but why can't you just get joist hangers of a suitable depth for 9x2 joists?

 

[luisdesign]

These days, I would normally always suggest using joist hangers rather than sitting any joists on walls themselves. But get the right joist hangers so you don't have to notch the timber.

 

[aztectt2000]

Thanks all. Makes sense, I will go the joist hanger route.

I was also thinking about whether it would be possible to get joist hangers which are a few inches smaller than the joists and notching the joists so they sit (not load bearing) on the wall plate to give me a fixing for the facia and to not make the ceiling tooooo low. I'd need to check if smaller joist hangers would take the weight.

If I was smarter I would have built the structure just 1 meter more in from the boundary, thus allowing me 3m height....but hey.

 

[aztectt2000]

@RonnyRaygun see my comment above about ceiling height. Do you know if hangers sized for 6x2s would take the weight of 9x2s?

 

[RonnyRaygun]

@RonnyRaygun see my comment above about ceiling height. Do you know if hangers sized for 6x2s would take the weight of 9x2s?

Don't know which ones you have, but Speedy Standards give a SWL of 4.3kN for any joist up to 9", so they would be OK.

 

[aztectt2000]

Thanks Ronny, I'll find some of them then!