loft conversion

[huwloftconv]

I have a loft which is 13ft by 26ft, the roof joists need to be in the 26ft direction, I do have a central 4inch brick wall across the middle but having gone through a load of trawling, I'm pretty sure it doesn't have the foundations required to conform with building regs for supporting the joists. I'm thinking of just putting an RSJ across, have already discussed this with the neighbours and they are happy to sign a party wall agreement. Any one know roughly what size joist and subsequent timber joists I will need. Also, would the new roof joists go on top of the new steel or into it? I am not adding a mansard but it will be used as a bedroom.

 

[Deluks]

You should probably get an expert in, ie: a structural engineer. The local authority building control dept. will not approve any plans without the appropriate calculations anyway. Unless you don't tell them about it, which is much more hassle than it's worth in the long run.

Having said that, I'm curious as to what the answer would be, anyone know?

 

[splinter]

Roughly,
The calulation for joists width is half the span plus 2" eg 14ft halved =7+2=9" and just to confuse you for the amount off joists needed;-is divide widthby joist spacing round up number add 1
egwidth 4750 divided by 400=11.875=12+1=13 joists

 

[markie]

I have a loft which is 13ft by 26ft, the roof joists need to be in the 26ft direction, I do have a central 4inch brick wall across the middle but having gone through a load of trawling, I'm pretty sure it doesn't have the foundations required to conform with building regs for supporting the joists. I'm thinking of just putting an RSJ across, have already discussed this with the neighbours and they are happy to sign a party wall agreement. Any one know roughly what size joist and subsequent timber joists I will need. Also, would the new roof joists go on top of the new steel or into it? I am not adding a mansard but it will be used as a bedroom.

Do you live in a semi/terrace ? Why do the joist have to go in the 26ft way ? could you give a bit more imfo, more the better,

A 8m joist is a hell of a lenght,

 

[Static]

Youll need to think about supporting the rafters too, are they purlin'd or trusses or loose pitched?

 

[splinter]

I have a loft which is 13ft by 26ft, the roof joists need to be in the 26ft direction, I do have a central 4inch brick wall across the middle but having gone through a load of trawling, I'm pretty sure it doesn't have the foundations required to conform with building regs for supporting the joists. I'm thinking of just putting an RSJ across, have already discussed this with the neighbours and they are happy to sign a party wall agreement. Any one know roughly what size joist and subsequent timber joists I will need. Also, would the new roof joists go on top of the new steel or into it? I am not adding a mansard but it will be used as a bedroom.

Do you live in a semi/terrace ? Why do the joist have to go in the 26ft way ? could you give a bit more imfo, more the better,

A 8m joist is a hell of a lenght,

It wouldn't be 8m long if there is a rsj mid-way.

It a bit of a puzzle to me why the joists need to run the oppisite way to what they are now