Steel bean cavity wall sizes

[Benway]

Hi.

Getting builders quotes for a single storey rear extension and it has been pointed out to me the the SE has specified 2 x 305x165x46 UB for a cavity wall that has a total width of 260mm. I have drawn it out below, does this sound/look correct?

The span is quite long at 6.5m and it also supports an internal structural wall and the new roof of the extension. The beams are planned to be above current ceiling heights.

What am I going to do with the sticky out bits>

Cheers.

 

[Doggit]

Iit's possible that the internal beam is to support the cross member, more so than the inner wall skin. On that basis, then you would start the outer beam to be flush with the outer wall. The inner beam would then be below the floorbards, and above the ceiling.

The SE may be able to specifiy a narrower, but taller pair of beams tbough, so it's best to have a chat with him.

 

[Benway]

Thanks.

The questions has already been put to him so hopefully will have an answer Monday (He doesn't seem to work at 11PM on a Saturday night! I'm not an expert but shouldn't the web of the beam be central under the wall it's supporting? I don't want to go thinner or higher, my toilet soil pipe is rapidly moving up to the centre of the wall!

Cheers.

 

[^woody^]

You won't be having a 57.5mm cavity surely?

What insulation will fit in that? Or are you insulating internally?

 

[Benway]

That's the cross sections of the existing rear of the house.

Cheers.

 

[^woody^]

The engineer should have considered a PFC for the outer leaf

 

[tony1851]

Those beams are just bonkers.

 

[Benway]

Are we saying they are too large? There is quite a bit of "stuff" attached to them. Should I check the engineers working out? I can supply his homework if you want.

 

[tony1851]

In terms of domestic loadings, a 6.5m span is not excessively long, and shallower beams should almost certainly be possible. By all means post the figures here,
but cut out addresses/ID.
In many instances, SEs purposely over-estimate loads to make life quicker and easier when doing the figures.

 

[noseall]

Those beams are just bonkers.

We know all about bonkers beams Tony, innit.

 

[Benway]

Hopefully readable

 

[tony1851]

We know all about bonkers beams Tony, innit.

You certainly do with that huge beam about a year or so ago!

 

[Benway]

So is it as bonkers as first thought?

 

[tony1851]

Don't know because can't see any load values?

 

[Benway]

Ahhh, I'm guessing that would be these?