installing RSJ in the attic

[brightlights]

I'm planning to convert my attic into a rec. room and because I have to convert the attic firstly from a trussed roof into a pitched roof,an RSJ has to be installed.I was wondering do I have to install the RSJ the full length of the attic on both sides and what lengths and sizes must I use and how deep into the block work do I have to cut.

 

[^neo^]

You'll need a structural engineer to do the calcs, but usually 4-6" bearing on each wall, and will need to check the walls are up to the task. Will probably have to put a padstone on top of the wall where the beam sits. Can get away with having a join in the centre of the beam if access will be an issue, but it must be plated on all 4 surfaces of the I beam, usually spans back around 500mm from the centre join with 10mm steel plate.
Structural engineer will tell you all this though

 

[Shytalkz]

You'll need a structural engineer to do the calcs, but usually 4-6" bearing on each wall, and will need to check the walls are up to the task. Will probably have to put a padstone on top of the wall where the beam sits. Can get away with having a join in the centre of the beam if access will be an issue, but it must be plated on all 4 surfaces of the I beam, usually spans back around 500mm from the centre join with 10mm steel plate.
Structural engineer will tell you all this though

Not necessarily and it's best not to do it in the middle of the span, due to the forces along the flanges; much better 1/3 of the way in.[/b]

 

[^neo^]

You'll need a structural engineer to do the calcs, but usually 4-6" bearing on each wall, and will need to check the walls are up to the task. Will probably have to put a padstone on top of the wall where the beam sits. Can get away with having a join in the centre of the beam if access will be an issue, but it must be plated on all 4 surfaces of the I beam, usually spans back around 500mm from the centre join with 10mm steel plate.
Structural engineer will tell you all this though

Not necessarily and it's best not to do it in the middle of the span, due to the forces along the flanges; much better 1/3 of the way in.[/b]

Just going on the drawings from structural engineers/ architects i've had to make beams to over the last 20 years

 

[brightlights]

Thanks,I understood mostly everything that you said,except for the padstone part,is this a support block which is fixed directly to the wall to take the weight of the RSJ???.

 

[Shytalkz]

It replaces brick or bricks in the wall and the beam sits on it.

 

[seasickstevie]

Often wondered what's best to use for padstones. Does it for example, have to be stone?

I've recently put in a large (2.2m) lintel and cut a 50mm reinforced flag up for padstones. Is this standard practice?

Previously I've used much thinner, none-reinforced flags.

What would an SE think?

 

[Shytalkz]

Steel plate.
Engineering brick.
Insitu concrete.
Prestressed concrete.

All valid options.