Beam to support Patio doors

[africadan]

My builder is building an extension which is 3800mm wide by 3000mm .

At the 3800mm end I wanted a open patio door of 3000mm. But he is saying that he has to put in 300mm to support the beam at both sides.

But surely - 3800 - 300 - 300 equals a 3200mm gap. but he is saying that he needs 300mm away from the side walls?

is this right?

Daniel

 

[MarkBarl]

Assuming that 3800 is the outside dimension, you also have to allow for the thickness of the bricks as you will not want the beam sticking out either end, also if it also goes on the inner skin you presumably have to make allowances for the cavity.
I'm not a builder though and may be talking rubbish.

 

[noseall]

structurally, you must have 675mm returns at each end, regardless of lintel bearing.

unless a structural engineer can prove otherwise.

assuming these walls are the free external ends of an extension that is.

 

[MarkBarl]

structurally, you must have 675mm returns at each end, regardless of lintel bearing.

unless a structural engineer can prove otherwise.

assuming these walls are the free external ends of an extension that is.

My calculator says maximum width of patio doors 2450 then.

 

[DenzB]

Because of this and your previous post re: maximum permitted glazing area, I assume this job is being done under Building Notice rather than Full Plans. This perfectly illustrates the inherent problem with this method of approval. Fine if all parties (client, builder and local authority) have a clear understanding of expected outcome and working method, otherwise, as in this case..let's just say headless chickens come to mind.