Structural Beam-advice pls!!

[Ap2904]

Hi,

Currently having an extension built 8m in length and 3m wide. Iv asked the SE to remove the wall between extension and the old house, and a beam for the new extension back wall where im installing bifold doors. He has advised a 305x305x97kg uc on 550mm piers of exsisting wall.He then advised the same UC in the extension back wall where i am having approx 7m of bifolds.

I am just concerned on two things:

1. The orignal house is wall is 250mm inc cavity, why would he suggest a 305UC97 and not a 254uc? It is a standard two storey house.
2.why he is suggesting the same beam for the new extesnsion back wall where the liad is only of a 8mx3mx tiled toof? I am however having bifolds across this wall and he mentioned something about deflection and causing problems with the bufold doors in the future.

I was thinking of getting another SE to calculate and compare but thought i would ask for some advise before i do, the 305UC97 is nearly 750kg in total so want to be sure its correct before i commit to a crane!

Any help is appreciated.
Ap

 

[tony1851]

A 305 UC is far too big - a 254 will do fine on that span, both for stress and deflection (assuming two-storey house with no unusual loading).

Same old story; some SEs don't take the time to do proper loading calcs so take the easy way out, pick a big figure off the top of their heads, and the client foots the bill for an over-weight beam.

 

[Ap2904]

Thanks tony!

I kinda guessed it was overkill!

There are no unusual loads, its just a standard property. I think il try an find another SE!

Ther first SE i used for some other beams was also hellbent on putting the most heaviest beams everywhere bolted together and all sorts, which we actually installed! However i decided i wont use him and try a new SE for this new job!

Are there any SE's on this forum who can assist?