Using joist hangers for polycarb carport

Wavey

Hi

I am building a polycarbonate roofed carport between 2 existing buildings.

It is essentially closed in on 3 sides and open on the south-west side.

Roof area is 4mx6m - Joists are 7x2.

This area does take serious gusts when we have a red wind warning.

Is the roof joist arrangement I have started good enough to hold the roof down?

Perhaps some upside down hangers also on the outer joists? But this seems a rough ugly job.

Any advice?

10-10-20

What bolts are you using to secure that wall plate/ledger to the block and how many? I can only see 6 on the left side and the wood also appears to be jointed. They look undersized to me.

Same question for the attachment to the shed. A shed is a self-supporting structure, no way was it designed to take the loading of a car-port. I think you'll need uprights against the shed. They can be retrofitted into post-holes and the ledger placed into a cut-slot.

standardg60

Hangers should be fine, I'd put a couple of screws up through the bottom holes into the joist too.

The polycarbonate would be way more likely to blow off itself rather than bring the joists with it, so make sure that's overly secured.

Calahonda52

what length is the overhang?

google wall plate tie down straps for stuff like this

SABREFIX ROLLED EDGE RESTRAINT STRAP TWIST 600MM 5 PACK

is from screw fix, wont allow me post the url

The screw fix is just to show you, I think their stuff is sh$te

I concur with 10 10 21 re the shed, is it on a concrete plinth.....

Lumen

IMO those joist hangers are intended to keep the joist from falling down, not up. The nails are there to stop it from unseating, not to resist loads..

Add some straps (as per Calahonda's suggestion) if you want it to resist lifting.

Calahonda52

https://www.boards.ie/discussion/comment/121846372#Comment_121846372

+1

in addition OP you will need to address uplift on the shed side as well, all the way down to what I think is a concrete plinth

The shape is wedge shaped so a lot of uplift at the door end so you might consider some sort of hit and miss type ventilation

is the gutter at the door end?

Shoog

Make sure that you have intermediate screw downs at the edges at 30cm spacings. They are special washers which distribute the load. Any further and the poly carbonate will flex and pop out under wind load. The weight of the roof suggests that you can economise on joists but that would be a mistake.

Also where is all the water going To go ?

Squatman

that looks seriously underspecced. the only silver lining is that the wind should break the perspex sheets. That shed, unless there is heavy structural steel, and you have bolted into it, is not build for what you have done. in fact, only the bit that's bolted to the house is secure., and even at the, I think it would benefit from more bolts. The hangers wont keep the boards down, and the nails in the hangers are at the end of the beam, so likely would offer much resistance to wind. you have a massive area there, which will ultimately become a kite in a storm. Think of trampolines in the wind.

GreeBo

It also looks like your joists are not actually hanging in the hangers, they are being held up off the hanger by nails?

Calahonda52

Only a matter of time

Wavey

Thanks for the replies.

Timbers on concrete wall are held with 6 x M8 rawlbolts. I will add brackets at front, center and rear with additional M10 bolts.

On shed side the timbers are held with 6x M10 carriage bolts with large washers on inside if shed. I will add 3 legs to take the load to the concrete base.

I will put a gutter on the gate side to take the rain.