Does this lintel need SE calcs

[ln1234]

We'll like to knock through a supporting wall between dining room and kitchen.

BC will be informed, but do we need to get SE calcs for the lintel? Builder has an idea of which type of lintel to use, but he's not an structural engineer.

thanks

 

[freddiemercurystwin]

You may be able to get one of the lintel manufacturers to do a quick calc for you, it depends on the span/loadings etc which you've left out of your post! Failing that if BC want proof you'll have little choice but to appoint an eng. Will probably depend on the BC officer, if he knows his stuf and your builder is about right you may get away with it however if the BC officer is wet behind the ears or your builder's choice looks a bit thin you won't. Would'nt cost much for an eng anyway, maybe £100 or so.

 

[^woody^]

No standard lintel, used as per the manufacturers guidance, in a typical domestic setting will require calcs.

Some LA's will also pre-approve steel beams up to something like 3m spans

 

[mikric]

Beware though I have known Catnics and similar fail on some knock through jobs when manufacturers have been asked to do calcs to back up their use. Had one the other month , calcs came out at over 8 tons catnic was only good for 5 tons, £1000 worth of lintel already on site and installed.
Not trying to scare you but just a heads up
As mentioned before we need a bit more info on your proposal ?
Also worth mentioning about BCOs, they do not have the insurance backing to design beams for you, hence why most "wet behind the ears " ones ! or sensible ones ! leave it to the expert structural engineers to do the design.

 

[^woody^]

A £1k lintel and 8 tons load WTF!

What size/model was that? It does not sound like a typical situation

 

[mikric]

will pull the file tomorrow if I get time, and let you know but from memory was 4.5m + CN99 with floor load from both directions + wall and roof, cant remember if UDL though.Let me come back to you on this Woody.Price wise only going on what builder told me.

 

[mikric]

yep was a catnic CN99 4.8 long, calcs worked out at over 7 tons, SE spec for beam was 2 230x90 PFCs bolted together.
Probably not what you would call a typical knock through, but all the same involved removing a downstairs 4" wall in a dwelling, just wanted to point out things are not always as straight forward as they my appear.

 

[Shytalkz]

Be interesting to see just how 7T was arrived at; and how much of that was live loading.

Ooi, 4" wall and SE specc'd 2/90x230s...how were they supposed to sit on a 4" wall, or does the opening extend full width?

 

[mikric]

Opening was from external to party wall.And I dont even pretend to understand calcs