opening up an external wall into our new extension

[russ135uk]

Hi,
I'm opening up an external wall into our new extension, The plans say use two universal beans 203x102x23kg but i've been told that a 3m (cutting it down to 2.8m) catnic lintel CG50/100 will be ok to use. The Building inspector said speak to my architect and when i spoke to him he said speak to the building inspector!

The catnic lintel is being given to me free so if it'll do the job i'd prefer to save some money, but if it's not safe to use i'll get the UB's.

P.S no joists sit on the back wall as they run parallel to the back wall we're removing.

the opening is 2.5m and it'll sit on 150mm on the existing back wall and on the internal adjacent wall into the cavity.

 

[noseall]

I would use whatever an insured structural engineer instructed me to use.

However it may be possible to glean some info' from Catnic as to whether their lintel may be suitable, though be prepared to receive only generic info', unless the details you give them are lengthy and specific.

Do not cut a Catnic down as you may lose the end weld as well as losing the paint coating.

3m is no hill of beans so you may drop lucky.

 

[russ135uk]

I've e-mailed Catnic this afternoon so i'm just waiting for a response.

One end is already bare metal, it has been stood on it's end. I'm going to touch it up with some anti rust paint (red oxide?)

if i don't' cut it down it'll mean breaking into my lounge wall and i don't really want to do that. I'll check to see if there is a weld though that i'll be cutting off. if there is i'll reconsider breaking into the lounge wall.

 

[^woody^]

Any standard lintel will be fine as long as

it is the correct type for the type of wall
it has adequate bearings (ie 150mm typical)
there are no point loads on it or uneven loading
loading is suitable for the lintel (ie standard or high-load lintel variants)

But in short, a catnic would normally be OK for a straightforward opening with no wacky loading on it

Its odd that those beams were initially specified as they seem way over the top for such a small span of 2500mm. Lazy designer?

 

[russ135uk]

They both said it's "belt and braces" method. They said it's better to be extra safe and over compensate.

 

[russ135uk]

BI passed the lintel. Thanks for those of you who helped me with the query.