Joist hangers for skylight

[danrhope]

Hello there,

We're currently in the process of having our flat roof , cross-battened and refelted.

There's a skylight, which is held up on a frame supported by wrap-over joist hangers. While removing the old firrings to cross-batten the roofers pulled up the wrap-overs on the joist hangers. Now they have cross-battened, put the new firrings on, the deck and the first layer of felt and I have just spotted that they haven't replaced the wrap-overs on the joists.

They are refusing to go back and correct the work, saying that what is there is more than adequate. The roof light is around 120kgs plus all the surrounding timber and deck. I guess 250-300kgs total supported on these four joist hangers.

I thought I would check here for some informed opinions before getting the building inspector back in.

Thanks
Dan

 

[danrhope]

To be clear it's the four joist hangers supporting the longer timbers running the length of the room.

 

[Deluks]

It will likely be ok, it will be a load of work to remove felt and deck to redo it.
Not all joist hangers are the wrap over type, and they work fine.
It's more important that there's a nail in every nail hole, and they need to be twist sheradised nails, not just any old nail.

 

[danrhope]

When you say it will likely be okay, do you mean it will definitely be okay?
I have read that the hangers that don't wrap over are for light duty tasks like flat roof ceilings, garage roofs. Structures that don't bear a big load or where the load is spread over multiple joists at regular centres.
It will be a lot of work to redo this but it's a mistake and it's my family's safety that's under threat.

 

[Alastairreid]

Get them to change the hangers for heavy duty face fix.

 

[danrhope]

The headers are blocking access to the trimmers, so the hangers can't be changed without dismatling the whole thing

 

[DAZB]

It's a scruffy looking job at best with missing nails (especially up the side and base of the timbers), nails not hit fully home, split laths, ragged lath ends, etc... have you paid them in full ?

 

[danrhope]

So... the skylight was done by another roofing company who completely made a hash of it. I mean, seriously. They didn't cross-batten so there was no air flow, they installed fascias that didn't even cover the rafter ends and in one point used OSB where they must have run out of fascia. The cut joists had sagged before they reattached them to the trimmers so we had a big puddle on the roof. It was awful.
We got our money back and this new company came to put right the wrongs. So far they have been really good, but this joist hanger business is really getting us down. We have a five month old baby and this three day job has been going on for about three and a half months now.

 

[catlad]

Looks a mess, the far end needs another joist at least, bad practice to cripple all those joists.

 

[cdbe]

What he said, looks a lot of weight to hang off a couple of single joists - I think this would be my main concern.

Regarding the hangers, you could contact the Expamet technical department for advice, or even just show your builder the technical information which clearly shows that's not acceptable.

While I think most here would agree that you're not going to suffer catastrophic collapse, there's a possibility that something there could settle/drop a bit over time and make a mess of the ceiling.

It can't be more than a few hours work to add some additional angled brackets to restore your faith in the job and the builders - they can be bolted as well as nailed so a bit more flexible for fitting in tight spaces.

 

[noseall]

To be clear it's the four joist hangers supporting the longer timbers running the length of the room.

They will be ok. When you consider that a couple of nails can support a huge weight, you have more than adequate fixing there. As said, supplement them with some galv' angles, if you want belts with your braces.