installing steels in loft conversion

[angela17]

Hello New to this site but hope someone can advise
We are doing a loft conversion and we have to put in rsj but on the drawings the rjs go one way ( from chimney breast to outer wall )and the joist another way( from front of house to back) and the rsj go under the joists , any thoughts would be gratefully recieved
thank you

 

[freddiemercurystwin]

Do you have a specific question? Generally when carrying out loft conversion the timbers can sit within the web of the steels to get the floor level down and maximise floor to ceiling height in the new loft rooms. Why haven't your engineer/architect done that? Was that your question?

A bit like this:

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• freddiemercurystwin
• 14 Apr 2010
• 12

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• freddiemercurystwin
• 25 Apr 2010
• 24

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• freddiemercurystwin
• 8 Jun 2010
• 20

 

[angela17]

Thank you for the post very welcomed
I probably wrote my question wrong but it something like that my husband is baffled with !!!!!!!! i will get him to post when he is home ( I am trying to help ) in the mean time i attached our plans sorry it wont let me as there pdf
[/url]

 

[freddiemercurystwin]

You'll need to convert your images to jpgs, just email them to me if it is easier and I shall convert them, my email is in my profile.

 

[freddiemercurystwin]

There are no steels shown on your drawings, just a note to say that engineers calcs are to follow! I would imagine the steels will be set down within the floor zone as per my details. Do you have any engineers drawings yet?

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• freddiemercurystwin
• 15 Aug 2010
• 1

Hope you didn't pay much for that drawing!

 

[angela17]

I have manage to convert file at last Think i didnt send you full one sorry i will scan the calculation plan and put them on here now i figured how to do it
thank you

Drawings

• angela17
• 15 Aug 2010
• 1

 

[freddiemercurystwin]

No I got the whole file but only posted the relevant bit.

 

[angela17]

Hello here are the calculations

calculations pt1

• angela17
• 15 Aug 2010
• 1

calculations pt2

• angela17
• 15 Aug 2010
• 1

calculation pt3

• angela17
• 15 Aug 2010
• 1

Thank you

 

[angela17]

hi there all, the question I am stuck on is the universal columns need to go at the same height as the current joists but unfortunately the steels need to run at right angles to the joists. so i need to remove all the joists to install the steels HOW??

 

[freddiemercurystwin]

Your engineer has specified that the beam sits above the existing and new joists so the new joists are beneath the steels. I don't know why the new joists run the full length only your engineer can tell you that. In anycase he has specified Simpson JHA450 hangers, there's a diagram showing the installation on this PDF http://www.loft-rooms.com/jha.pdf

 

[angela17]

thanks freddy glad you can see the detail. but if you look carefully you'll notice that the dormer is offset. Consequently i can raise the wall where the steel is in the dormer but not where its in the untouched roof. When I pointed this out to the building control officer they agreed that I could remove the old joists and set the new steels at that height and slot the new larger wooden floor joists in. good plan, i thought but I'm not sure how to proceed. I'm an engineer not a builder. I can brace it all heath robinson style but I'd rather do it in a more agreed professional manner. any ideas ? very welcome thanks

 

[freddiemercurystwin]

I don't really follow tbh. I don't understand why your steels aren't sat just above the existing joists and the new joists sit in the web of the new steels. Why do the new joists need to span from the steels to the outside walls when there's no floor to support (as per my details)?

 

[angela17]

cheers freddy well spotted the joists don't need to go to the outside walls, so I could leave them out, as it does say to do that in the drawings. but that isn't the problem. I cant put the steels above the joists because one end is in the party wall and the outside end would be five inches above the wall?? and i cant raise the wall as its not in the dormer??

 

[freddiemercurystwin]

I cant put the steels above the joists

You've spent the whole thread saying you want to fit the steel above the joists!

So are you saying that if you were to fit the steel beam just above the existing ceiling joists the end of the steel beam will effectively poke through the tiles on the outer wall? If so then you will either need to lower the steel beam enough and prop and cut the existing joists temporarily so that after steel beam has been fitted you can then get support from the web of the steels or alternatively your engineer will have to come up with a cunning plan to support the end of the steel at the external wall end, that's what they're paid for!

 

[angela17]

hi freddy yes thats my question, how to brace and tie together all the current joists, wall plates and rafters whilst removing said joists to fit new steels. I'm attempting to get an answer from my structural calcs people. hopefully like you say, they can suggest something. thanks for your time and input. much appreciated regards neil