RSJ sizes and pilar sizes?

[exepete]

Hello, just joined this forum. Looks like a great place for advice

So, I have a flat roof garage (chipboard+felt) 6m x 6m approx with an internal diving wall which runs front to back and divides the space into 2m+4m (workshop/garage). I want to remove the wall and make it one space. Local rsj supplier suggested 203x133x25 to replace the internal wall (which supports wooden ceiling joists) and then another 203x133x30 rsj above the new, extra-wide garage door opening. So a welded 'T' shape rsj.

Do the rsj specs sound about right for a flat wooden garage roof of this size? What size/shape pilars would I need to build to support the rsj over the garage door?

(the garage is not attached to the house, but it is sandwiched between the neighbors terraced garages).

I'd like to do as much of the work as possible myself, but I am prepared to get a professional in to do the pillars.

Thanks for any advice you can offer.
Peter.

 

[tony1851]

The beam over the door will be OK (assuming about 5m span). The main beam under the roof will be OK for bending stress (just) though may deflect a bit. If there is not suitable fall on your roof, you may get some ponding.

450 x 450 brick piers would be OK.

Strictly this is a Building Regs matter as you're over 30 sq m.

 

[exepete]

big thanks for that Tony. That's exactly what I needed to know.
5 degree slope that exits on 'flat' roof will eliminate ponding.

18" (450mm) pilars is what I thought. Thanks again.

re buildings regs; the exact outer dims are actually 5.9 x 5.4 = 31.9m2
v. close to threshold. But may still need to comply.

 

[tony1851]

re buildings regs; the exact outer dims are actually 5.9 x 5.4 = 31.9m2
v. close to threshold. But may still need to comply.

It's based on floor area, so you might just be OK.allowing for piers/thickness of walls.

Also, it must be either at least 1m from the boundary or built of substantially non-combustibe materials. If yours is brick with a timber roof, you will be 'substantially non-combustible'.

 

[exepete]

excellent news! Thanks a million Tony,
Peter.