Room in the roof wooden portal frame?

[dsj1979]

Hi,

I've been working out possible ideas for a garage/house I'm planning. I've come across a portal frame type roof structure? Has anyone used this before? It seems mostly if not always to be used in metal.

I like the design as I could make two stories, one in the roof and lower the floor in the attic space thereby making a more useable room. If that makes sense!?

Does anyone know anything about this design or similar? And is there a way of making structural calculations with it or would an architect have to do that?

Thanks,

Daniel

 

[freddiemercurystwin]

If that makes sense!?

No, much of your post makes little sense, please re-write it, a structural engineer provides structural calculations not an architect BTW.

 

[dsj1979]

Most roof designs when you want to use the roof space are a 'room in the roof design', the joists on these are at the eaves level. I've seen a roof type called a portal frame design. The joists are lower than the eaves which is a good design, that'll give more head height so make the space more useable.

I've attached a link, the portal frame is at the bottom of the page!

http://www.harlowts.co.uk/pdfs/2_trussedrafter.pdf

Has anyone used this type of design? Or know of any similar where the joists could be lower than the eaves to increase headroom?

Hopefully that makes more sense! I presume if I made a design based on this and gave it to a structural engineer he could say if it worked or not, and that would satisfy building control?

 

[dsj1979]

Anyone?

 

[freddiemercurystwin]

Doh! Didn't see your reply from Sunday, the idea of using trusses such as these from a manufacturer, is that they do the calcs/design that satisfy Building Control so no need for an engineer. There is no problem using them. TBH I'm still not quite sure about the bit where you say

Has anyone used this type of design? Or know of any similar where the joists could be lower than the eaves to increase headroom?

I don't think its just me, that's why you've had no other replies! If you're referring to the portal frame truss in your link there are no joists shown on that truss!

 

[Static]

Doh! Didn't see your reply from Sunday, the idea of using trusses such as these from a manufacturer, is that they do the calcs/design that satisfy Building Control so no need for an engineer. There is no problem using them. TBH I'm still not quite sure about the bit where you say

Has anyone used this type of design? Or know of any similar where the joists could be lower than the eaves to increase headroom?

I don't think its just me, that's why you've had no other replies! If you're referring to the portal frame truss in your link there are no joists shown on that truss!

The whole point of a portal frame is you dont have a tie across the bottom, the frame is designed for the moments generated (nice and simple with steel, not so with timber)..
But to answer the Ops question, no its not common place, no ive never designed one, no i hope i never have to.. go for attic trusses if your planning something in the roof, or simple cut roof with apex member.. the more complex you try to create things the deeper your pockets need to be.. grand designs arent normally cost effective..