Advice and comments on doorway and concrete lintel needed.

adamex said:
Is this right?
Click to expand...

Not quite.

Total area of floor supported is 4.55m2, so with a floor live and dead loading of 2.15 kN per m2, that's 9.7 kN total load , and not 9.7 kN per m2.

But, you should use the effective span and not the actual span. :oops: Sorry.

Either interpolate the effective span from the table, or just use the 1.5m span 1.58m effective span figures which will give a slightly higher load.

So work the area out again based on the above and then .. Divide total load by effective span to give a UDL in kN/m - which should be less than in that lintel table.
 
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The high-tensile steel wires will run through the middle of the cross-section because it will be a 'pre-tensioned' beam. How it works is that they put steel wires along the mould and then subject them to high tension through clamps at each end and then pour the concrete.
Once the concrete has set, they release the tension in the wires, which puts a 'pre-compression' on the concrete. This enables it to carry a higher load. It also means there is no difference between top and bottom of the lintel - it can go either way.
It's a more efficient system than the old way of having bars att he bottom (tension) zone of the lintel.
 
Ok, thanks again for all replays, Tony cheers as well, I just had a conversion with lintel manufacturer and they said that the rough side has to go up as it will have better bonding properties.

I have done the calculation and it worked out at 6.97 kn/m UDL over 1.58m span, so I have some room for extra weight from upstairs.

I think that's all I need right now, tomorrow I will get some slate and put it under the beam and set it on the bead of mortar.

Will take another photo when everything is done.

SPECIAL THANKS TO WOODY !
 
Last edited:
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adamex said:
I just had a conversion with lintel manufacturer and they said that the rough side has to go up as it will have better bonding properties.
Click to expand...

The reason for that is that it is probably a 'composite' lintel, which is intended to be built-in as work proceeds. Part of its strength derives from the bond to the masonry above which helps to increase the depth of the compression zone and so enables the relatively shallow lintel to span a greater distance. But on the span you have - which is relatively short - not being built in won't make any difference, and it will be fine.
 
Ok, Lintel is beautifully level siting on thin bed of mortar, above gap keyed in 5 places with slate, slate was gently hammered nice and tight. Everything looks great but something bothers me. I attached photo of left side, that brick with red, does this course of bricks look safe? All four of them are starting at same point creating long line of mortar, would you recommend to maybe tie this red brick with one next to it (green)? Maybe I am paranoid a bit. but just want to do top job here, this is my house :) Thanks.

tie.jpg
 
yeah you should see some of the things we all find holding up lintels
 
thanks a lot, I wish I knew some good builder, would not have to bother you all the time!
I will add to this post in the future when my opening is all good and plastered, for now I am moving to another job, this time a bit simpler, fitting new patio door... Cheers again!
 
Dont forget to get building control organised before covering it up,

Neat job thou.
 
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