What lintel do I need?

R

richard7761

Domestic home. The ground-floor internal wall is load bearing, it runs through the centre of the house from gable end to gable end and it supports beams.

There is a door in the wall, that is is 30" or 760mm wide. Above it is concrete lintel of some description (presumably re-inforced - not sure. House built in 1958).

The size of the lintel above the door is 1060mm long, (assuming 150mm on either side), x 150mm deep, and 110mm wide.

Okay, in the same load-bearing wall I'm making another doorway 65Cm from the original one..

The width of the new doorway will be 680mm , so I'll need a lintel about 980mm.

Okay, taking into consideration the size of the lintel over the original doorway, what size of lintel do I need to buy for the new doorway?

Do I need a special type of lintel considering that the wall is load-bearing? Or, just a regular re-inforced lintel?

Do I need one about 980mm x 120mm x 150mm? Or what ? Thanks.

P.S.

Let me just add this:

The wall that is load-bearing, which is holding up beams is brick, single skin, and half-brick width. Also, the beams do not rest on each side of the house, they interleave (side to side) at the load-bearing wall. So, the beam end points do rest on the wall as oppossed to a beam that goes from one side of the house to the other, with central point resting on the wall.

There will be four courses of bricks above the lintel before the beams.

I think concrete lintels are used for load bearing single skin internal walls. That's what I've read.
 
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R

richard7761

I think I need a 100mm, non-composite, lintel that is between 140-150mm deep. I imagine we are talking pre-stressed concrete. But, I'm just learning about lintels. :D

This, I believe, pretty much mimicks the lintel over the original door, which is a larger span. Probably a stronger lintel than the original 1958 lintel. Non composite lintel would be good - possibly essential, there are only 4 courses of brick above the new doorway.

That's how far I've got. I think I'm right.
 
R

richard7761

You've solved the problem yourself.

Hi. Well, that's what I thought, but confirmation is required and is sought for.

I do wonder whether calculations are required for some purpose. But, because of the shortness of the span (680mm) I reckon perhaps I would not have to show calculations to anyone. I wonder am I right on that point?
 
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You have not mentioned supporting the wall/joists whilst inserting the lintel. Its possible that the wall is built in lime mortar so I would suggest that you used acrows too support the ceiling
 
R

richard7761

You have not mentioned supporting the wall/joists whilst inserting the lintel. Its possible that the wall is built in lime mortar so I would suggest that you used acrows too support the ceiling

I thought I might be able to get away with no support for the time it took to get the lintel in. But, maybe it is wise to provide some support. :)

There would be 3 courses of brick holding the beams up across say a 1060mm span.
 
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You've solved the problem yourself.


I do wonder whether calculations are required

On a 680 span with a 140/150 deep p/c concrete lintel, no Building Inspector with more than a grain of commonsense would ask for calculations.

It doesn't matter if there are 20 stories of building above the lintel, it will still be carrying exactly the same weight, which is that of the small tiangle of brickwork directly above it.

If that were my job, I'd have just used a piece of 4x3 timber, which would be a lot easier and just as good.
 
R

richard7761

How should the lintel be put in?

I do not think I will need padstones.

I do not think I need to use engineering bricks (maybe wall could be engineering bricks, because it's built as a load bearing wall).

I think I do need to have lintel sit on cement.

I think I need to use shims along the top of the lintel.
 
R

richard7761

You've solved the problem yourself.


I do wonder whether calculations are required

If that were my job, I'd have just used a piece of 4x3 timber, which would be a lot easier and just as good.

Yep, absolutely. I bet a good timber piece would do.

But, let me let you into a secret: I'm doing this in a council house! :rolleyes:

And, if anytime a man from the council says I did it without permission I want to be able to say, okay, true, but this is what I did, and it's plainly acceptable. Now, give me that permission retropectively. :D

I'm going to photograph my work. Just in case.
 
R

richard7761

Going by what I read on the internet, it appears that I need a non-composite lintel.

I phoned up my local supplier (Jewson's). But, the person has no appreciation of non-composite lintel. All come pre-stressed and that's all there is to it. So, I guess nobody comes asking for non-composite lintels.

So, I guess, I don't bother asking for a non-composite lintel, because no-one thinks anything of that. Seems odd to me though, I thought when I mentioned non-composite the guy would know all about it. And how they are for higher load-bearing capacity.

I'm wondering, does my experience tell me the supplier I contacted does not stock non-composite lintels, or it's just an ignorant custmer service operator I talked to.

I've contacted Jewson to see if they do indeed stock non-composite lintels.
 
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I think you'll find that all the 75 deep lintels are regarded as composite (ie they need extra brickwork on top to work). Above this depth, it will depend not only on the number of courses but also partly on the span as to whether they work as composite or not.
For your short span (<700) a 140/150 deep lintel will be fine and on this span, 'composite' or 'non-composite' will be irrelevant.
 
R

richard7761

I think you'll find that all the 75 deep lintels are regarded as composite (ie they need extra brickwork on top to work). Above this depth, it will depend not only on the number of courses but also partly on the span as to whether they work as composite or not.
For your short span (<700) a 140/150 deep lintel will be fine and on this span, 'composite' or 'non-composite' will be irrelevant.

I had a change: Now the span is 850mm. So, I need something like 1200mm x 100mm x 140mm lintel. There would be three courses of brick above the lintel. Again: the middle-placed load-bearing wall (running parallel with the roof ridge), is holding up the ceiling beams (bedrooms), and upstairs there is a breeze block dividing wall, parallel and in proximity to the load-bearing wall.

Does this increased span change anything? Thanks. Rich
 
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Even on that enlarged span, a typical pre-stressed conc. beam 140/150 deep would easily support around 15kN. This is around one-and-a-half tons, far in excess of what your beam will actually be supporting.
 
R

richard7761

Even on that enlarged span, a typical pre-stressed conc. beam 140/150 deep would easily support around 15kN. This is around one-and-a-half tons, far in excess of what your beam will actually be supporting.

Okay. It is a bit of a red herring (sort of) to feel that because I have only 3 courses of brick above the lintel, and the wall is holding up the ceiling beams, that I require a non-composite lintel. These non-composite lintels then must be made for taking unusually high loads not often encountered in your usual house situation. So, I'm okay with regular pre-stressed, composite lintel. That my take of the situation.
 

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