Lintel or RSJ

[Dash1]

I am currently building a small extension to the back of my house (3mx3m). When I have completed the brick work I wish to open up an exterior supporting wall. It currently has a window in which would have a lintel (i presume above). I want to make this opening as wide as possible.
The wall is 3m long, with support of 150mm at each end what size lintel will be required too ensure the correct support is there to take the floor and wall and roof above.
My house is a normal semi with pitched roof.

Any advice or information would be greatly appreciated

Many Thanks

dash

 

[r896neo]

You will probably need to bite the bullet and pay for an engineers calculation. Building control will want to see one anyway.

 

[spada01]

An external wall with a large opening - it's likely going to be an RSJ.

You'll need the building control officer to sign off the extension and he'll want to see load calculations for whatever you use there anyway along with the other calcs.

 

[^woody^]

You can get steel lintels that will support standard domestic loads at 3m spans. They may be easier to put in too, and will not require calcs if installed as per manufacturers guidance

 

[freddiemercurystwin]

This thread cannot be answered without knowing the position of the proposed hole and its position relative to the outside walls etc.

 

[hotrod]

.............or wall construction freddy - cavity thickness etc .

What's the max signature character limit, anyone know?

 

[PrenticeBoyofDerry]

It's likely to be an RSJ, but as stated before the section or gauge can not be given without more information and as the extension will need building control compliance, they may insist that calculation are made, so you will need a SE.

 

[Static]

If the roof spans from the new extension then its a dead cert for steel beam.. if it doesnt then you may be able to justify a standard lintel, but would restrict future development of the extension.