whats the right way for lintel?

[legepe]

Hi all
I want to place a 210 x 100 x 1800 concrete lintel above fire place, only 100mm will actually sit inside the wall the the rest will be on the outside creating a mantel piece
My query is should this lintel only be installed with the high side (210mm) sitting vertically? or am I wrong thinking this?
Can anyone advise
Thanks
legepe

 

[tony1851]

It depends on the span, but it is not adviseable to build-in a lintel in that way as the reinforcing wires will not be capable contributing much to the tensile strength of the lintel.

 

[Leofric]

A lintel that size would normally be placed with the 210mm as the height and 100mm the width, with preferably 150mm bearing on to brickwork or blockwork at each end. The steel reinforcement in the lintel should be near the bottom where the concrete will be in tension when under load.

 

[legepe]

It depends on the span, but it is not adviseable to build-in a lintel in that way as the reinforcing wires will not be capable contributing much to the tensile strength of the lintel.

Ive attached a couple of picks.. first one is one that I did around 6 months ago.. the second is the one that I want to do now. the span will be around the same.. I never realized I was supposed to put the lintel long ways up.. do you think that it will be ok? and do you think its ok to do the same with the second one? its a different type of construction in that above the opening inside the bricks start to narrow lower down.. i will have to remove this part of it to make the opening
Thanks
legepe

 

[tony1851]

Well, it seems to work OK; sometimes things work even though they aren't 'by the book'.
(depending on what type of lintel it is, there might be two layers of wires in it - one nearer the top and the other nearer the bottom,
in which case that improves matters slightly. See if you can see them at the end of the lintel).

 

[John D v2.0]

The lintel will only meet its specified strength of you put it the right way, but some are pre stressed so they would have reasonable strength either way. It seems unlikely that it would crack as it's still 100mm high. Did an se specify it to be those dimensions or did you just buy oneand Chuck it in?

 

[legepe]

The lintel will only meet its specified strength of you put it the right way, but some are pre stressed so they would have reasonable strength either way. It seems unlikely that it would crack as it's still 100mm high. Did an se specify it to be those dimensions or did you just buy oneand Chuck it in?

I just chucked it in so to speak... I do remember it had 3 wires that were visible at each end. (i think you can just see them in pic) there was an arch in the brickwork originally but it was knackered... The lintel is placed pretty much where the original arch was and i obviously I did not have to touch any of the inside where the brickwork tapers inwards up to the flue.. My other concern regarding opening up the current fire place is that to get sufficient opening i will have to break into the bricks that taper inwards/upwards to the flue. these are built down onto the sides of the fireplace and seem to be also load bearing.
Any suggestions?

 

[legepe]

After closer inspection... I am more concerned about opening the space behind the front skin of the fireplace because of the bricks tapering up which i now believe is called cobels.. I guess these are load bearing.. and how do i get around it.. any advice would be very much appreciated (see pic's - first pic - corbels, second pic 1st floor above)

 

[Leofric]

It is corbelled brickwork or corbelling and is part of the structure supporting the chimney stack .I would not interfere with it if you can help it.

 

[legepe]

It is corbelled brickwork or corbelling and is part of the structure supporting the chimney stack .I would not interfere with it if you can help it.

Thanks for that... any idea if I am able to get a reasonable size log burner in that space. without opening it up?

 

[Leofric]

Not without looking into it in a lot more detail but - clearance is required around a stove - looking at your photo a stove would sit out in front of the brickwork opening with a rear outlet flue - stoves need to sit on a concrete hearth of specific dimensions to suit the stove. Look at some catalogues of wood burning stoves or go into a local shop that sells stoves and they should be able to provide the details you need. Give them the size of the fireplace opening ,flue diameter and construction of the floor.
Regards