calculating the weight on a lintel

[RonnyRaygun]

I bow to your experience Woody, but what you say seems a bit odd, I need to bung in a 12 foot lintel which will sit on 6" of brickwork each side, so I will choose a catnic NN81B box lintel which the manufacturer says can carry 29Kn, surely the plan I submit must prove that there isn't more than 29Kn sitting on top of this otherwise no-one will know if the beam is correctly spec'd?

Yup, I've checked lots of lintels, and guess what, they don't always work!

You have to estimate the loads. Floors are about 2kn/m2, 4" brick about 2.1kn/m2, block approx 1.35, 0.25 for plaster and render, 0.6 for the loft, and up to 1.85 for a timber tiled roof.
You can just take a 45 degree triangle above the lintel if there is enough masonry above, so loft and roof don't necessarily have to be included on ground floor lintels in houses.

 

[DIYedboy]

Nice one Ronny, a man with figures and knowledge, very informative Thank you

 

[RonnyRaygun]

Nice one Ronny, a man with figures and knowledge, very informative Thank you

No probs. Just noticed you've got 9" brick. That's approx 4.5kN/m2.