New doorway

[catlad]

I have been asked to knock an opening in a wall to make two separate rooms into one by
putting some french doors in and bricking up the old doorway. The customer has informed the council and has the go ahead for the doorway. I know a building inspector will come and sign the work off, but I am not sure about if he is going to want to see some calculations
for the beam/lintel if it was 3mrs long then obviously I would need some calculations
but this is only going to be 1400mm wide. I think the question I am asking is there a cut off point were an opening becomes a must for a structural engineer to be required.
Thanks

 

[oldbutnotdead]

My experience with the BCOs up here is as long as you're using a fabricated (concrete or steel) lintel (rather than a chunk of RSJ) then they aren't bothered about calcs. Have a shufti through the lintel catalogues, pick the one that looks up to the job (with the right price), give BCO a ring and check it with them, I'd be amazed if they wanted anything more than the standard 150mm bearing at the ends, packed with slate as required.

EDIT- if you were removing the whole wall (ie not leaving any nibs to buttress the side walls) then that might warrant someone with letters signing it off- not so much for the lintel, more to do with the stability of the perpendicular walls. Might be worth giving BCO a ring & check that they're agreeable to whatever nib you're leaving in place

 

[Doggit]

You've given the width of the opening, but not the thickness of the wall. If it's a 225mm wall, then you'll need 2 x 1800mm concrete lintels (Wickes 1800 L05).

As long as you can get an off the shelf solution, then the BCO should be happy.

 

[catlad]

Thanks for the replies
This is a terraced house and its a single brick internal wall that is 12' wide
so I don't see any issues myself.

 

[Doggit]

How much loading (or what) is above the opening. This might be the only reason that a BCO would ask for a steel rsj, but I don't reckon he'd want more than 100mm. But there still won't be much of an issue. It might be worthwhile just ring Building control and having a quick chat.

 

[catlad]

Thanks I am going to give them a call tomorrow and see what they say.