Lintel above window

[cdh]

Building a 2 storey extension and need to put a lintel above the upstairs window, the span of the window is 1.9m. I intended to use a heavy duty catnic lintel, but the height of the lintel is fouling the roof trusses. If I was to use a standard lintel which is not so high, would this be strong enough (the roof is pitched with double roman 50 tiles)?

Thanks

 

[noseall]

Why a heavy duty lintel, was this specified by the engineer?

We had a similar situation a couple of years back and used a piece of 152mm x 89 (16kg) steel 'u' beam. The bco took one look and said "that'll eat it" and didn't even bother asking for calc's.

 

[Shytalkz]

Watch Cougar-type lintels as there are max ratios of loading between leaves. Often falls foul of this at eaves level, due to roof load on inner leaf and nothing on outside other than few course of brick.

 

[rou]

Hi there,
How much of the roof is supported by the lintel? It is very unlickely that a normal lintel will not work under only roof load as they can easily take a load of about 2tonnes for that span.
If there is a timber or steel beam sitting above the lintel then you will need to use a small steel beam instead as lintels cannot be used for point loads.

 

[Shytalkz]

Duh, it's not just the total swl, but with Cougars it's how it's put to the lintel. And, amazingly, lintels can actually take point loads too; where are you glibly trotting out such statements from?

 

[rou]

Shytalkz

Lintel specifications are clear. They can support a uniformly distributed load unless you can calculate the section properties yourself.
I am a qualified structural engineer and neither me or any of my collegues ever uses a lintel to support point loads beacause a small beam cost the same as it is a lot stronger.

 

[Shytalkz]

I'm not disputing that a beam is most likely cheaper, but it's most def not the case that a lintel can't take a point load as you infer in your post.

 

[rou]

Ok sorry I did not make myself clear.
A lintel can be designed to take point load. The design would take at least an hour as it need many out of ordinary check which most structural engineers are not familiar with (thin plate theory, cold formed section, etc)costing to the client at least 100£.
However, if you want to use the safe working loads given by catnic or any other lintel manufacturers tables you have to use the safe working load they specify. SWL is based on uniformly distributed load over the whole length of the lintel as stated on every lintel design tables. Therefore you cannot use the value of stated as SWL if is not uniform.
I specifically mention not to use point loads in this instance as it was mentioned that there was not much wall above the lintel to distribute point loads (if any) equaly.