lintel strength

[5pack]

Hi
I have been asked to create an opening 1-6m in what was the old outside wall of a house. Cavity wall brick/concrete block. Bedroom Floors Joists above. What type of lintels/padstones would be adequate?

Regards

 

[freddiemercurystwin]

One that your inspector will approve!

 

[rjm2k]

is that 1.6m , 1m to 6m or -5m ?

 

[5pack]

Sorry it's 1.6m . Glasses a bit scratched

 

[5pack]

Yes , it will be inspected. I used to be advised by lintel companys but they won't commit themselves nowadays and just to clarify the span is 1.6 metres
Regards

 

[^woody^]

Any lintel 200mm wider than the opening will do

 

[chapeau]

Any lintel 200mm wider than the opening will do

Is that correct? Does that include a 100 x 65 x 1800 concrete lintel ? Just pulled up a table and the uniform load allowed is 204 kg/m*. That's not a lot of wall/floor.

*(with a 150mm bearing not 100, so a 1500mm span, but I'm being kind)

 

[jeds]

All prefabricated lintels or beams have a safe working load. The only way to be sure you don't exceed that limit is to know what load you are supporting. An average floor and wall load might be 12 or 13kN/m, but you must be sure there are no other loads involved - particularly roof loads.

 

[RonnyRaygun]

Although if there is enough continuous masonry above the lintel, only a triangle of load has to be considered.

 

[chapeau]

But doesn't that still work out to approximately the estimate given by jeds?

(Have always thought the triangle method is a bit like smoke and mirrors)

 

[RonnyRaygun]

But doesn't that still work out to approximately the estimate given by jeds?

Well, only that if the lintel is above a ground floor opening in a two storey building, then if there is sufficient masonry above, none of the roof load needs to be considered as it will be transferred to the edges of the opening by the corbelling effect of the masonry.

(Have always thought the triangle method is a bit like smoke and mirrors)

Makes perfect sense really as the corbelling effect means that if the lintel was removed, only the triangle of masonry above would potentially drop out. The rest of the masonry should stay in place.

 

[chapeau]

Yes, it transfers the load somewhere else.

 

[5pack]

Hi
I asked building control if they would be happy with a pair of 8"x4" UBs on pads and got the reply "that should cover most eventualities" so 8"x4"s it is . Thanks Lads

 

[chapeau]

Stick a catnic in, works far better in an outside cavity wall. Easily done by a competent DIYer. You will have to work out the load to decide which one to use, go on the builder's forum ifyou want to know how to fit it, plenty of helpful people on there.

 

[jeds]

Although if there is enough continuous masonry above the lintel, only a triangle of load has to be considered.

That's true ronny - as long as the load is assessed correctly. As my struct-mech tutor used to say; if we draw little triangles around the whole building the upper floor and roof will support itself.