Cantilevered joists of an I beam question

[TimB100]

Hi all

I'm looking to see if anyone has any suggestions on how to solve a problem

I'm going to be building an extension to my kitchen. Its current design has a beam over the sliding door and the joists that stretch from the house connect to it.
Due to my design requirements I need the top frame of the S door to be higher than the beam.
So I'm thinking to bring the beam back 400mm (it will help also as it can sit on an existing wall and not require a box beam to support it)
Then cantilever the joists out another 400mm and resses the frame into the joists. The issue is the connection to the beam. I'm thinking perhaps bolting a joist to the beam then using a wrap around joist hanger to attach the joist.
Another alternative is to bolt large angle iron to the beam on both sides and bolt them to the joists both sides

Since the drawings etc are already done I'm hoping to just get the OK from the site inspector to get the OK on it. Else it will all have to go back to the Structural engineer to be calculated. I really do not fancy that though asit costs £££

Any thoughts appreciated

Cheers Tim
BTW attached is an image I hope makes the issue more understandable

 

[^woody^]

That view is not too good to make out.

Where are the walls, and the doors?

 

[TimB100]

Thanks,

The doors and walls are not relevant to the question. My query relates to the connection of canterelevered joist to the I beam.

Tim

 

[freddiemercurystwin]

They're not cantilevered, they're just hanging magically.

 

[TimB100]

Thanks

Yes in that image, how to secure them is my question.

Cheers
Tim

 

[freddiemercurystwin]

If you want to cantilever the joists, they'll need to be on top of the beam.

 

[cdbe]

Maybe provide loads more details (span, roof loading, distance from beam to doors, top or bottom hung etc) and see if anyone can come up with something that would be acceptable to BC or get your cheque book out and back to SE.

 

[TimB100]

Thanks

The info being asked for is in my original post but here is a new image that spells it all out
The only loading is the roof and fascia

 

[freddiemercurystwin]

Yea we know all that but what you're proposing simply doesn't work.

 

[TimB100]

Saying "it will not work..." is not an explanation why. Just saying NO it's impossible is not helpful
I see a few options like the one below

 

[freddiemercurystwin]

Seems good, go for it.

 

[cdbe]

Yes, I'm right with you on that, and the roof decking cantilevering over would help, and the doors sitting on the floor rather than hanging. I think the angle iron either side makes perfect sense, but it's not conventional and that's the problem - depends on the knowledge and experience of the man from the council to accept anything without calcs. I think there was a recent post where the plan was to bolt 2 or 3 8x2's to the steel to span the gap, but the twisting becomes an issue.

I honestly don't have much experience with building control, but I have found that most of the ones I've used have genuinely tried to help, and (maybe because I look so pathetic) have gone slightly beyond their remit and suggested acceptable shorts cuts and work arounds.

Send your picture to your BCO, but with them on both sides so there's no issue of tipping the steel over (there's a fancy name for that).

 

[TimB100]

Thanks cdbe

The twisting is an issue I'm worried about also so the bracket will be replicated on the other side. There are some dual beams on the long side that are 150mm wide. So attaching to them will mean no way it can be twisted.

I know replicating all those brackets is a lot of work but I have learnt a long time ago that going the extra mile is worth it as its a long term gain for short term pain.

Now as you pointed out getting building control to accept it is another issue. I'm hoping that as its only 400mm they may be

Another image showing the full option.

 

[blup]

Would it make more sense to have a u shaped bracket, one end bolted into the web and the other two sides around the timber beam

 

[TimB100]

I think I'm putting a big target on my back by having the 400mm overhang, and since all I'm looking to do is just recess the sliding door frame I am now looking at at just packing timber out bolted to the I beam as per image.