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100x100 Concrete Lintel


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H- My SE has specified for every door cut-out 2 x 100x100 concrete lintels. This seems a strange size and probably quite difficult to obtain and fit in. Is this normal?

 

Also an example of where I'm putting one. They are cavity walls (if you count 20mm as a cavity!)

 

95628266_BedroomLintel.png.9186a04d48a7784d3dd29787e623ca50.png

 

 

 

Office.thumb.jpg.0822310147bddcbc5068c0fc1e77a3c4.jpg

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1 hour ago, lstevensuk said:

H- My SE has specified for every door cut-out 2 x 100x100 concrete lintels. This seems a strange size and probably quite difficult to obtain and fit in. Is this normal?

 

Also an example of where I'm putting one. They are cavity walls (if you count 20mm as a cavity!)

 

95628266_BedroomLintel.png.9186a04d48a7784d3dd29787e623ca50.png

 

 

 

Office.thumb.jpg.0822310147bddcbc5068c0fc1e77a3c4.jpg

It’s fine 

I’ve just finished building the blocks on my chimney 

C7259009-5401-4196-8A14-A53A527B045D.jpeg

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1 hour ago, nod said:

Ps

Im not a brickie 😁

 

Thanks @nod Nice work 👋

I'm hoping I only need to stick 1 in each side. What's the best way to make up the difference in height - can you get a 35mm brick or would I need to cut some down?

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On 02/06/2022 at 09:32, lstevensuk said:

H- My SE has specified for every door cut-out 2 x 100x100 concrete lintels. This seems a strange size and probably quite difficult to obtain and fit in. Is this normal?

 

Also an example of where I'm putting one. They are cavity walls (if you count 20mm as a cavity!)

 

95628266_BedroomLintel.png.9186a04d48a7784d3dd29787e623ca50.png

 

 

 

Office.thumb.jpg.0822310147bddcbc5068c0fc1e77a3c4.jpg


they will be 9” or 215mm solid walls. I’d ignore the SEng spec and get 215x65 concrete Naylor lintels and put them on their sides - much easier to get hold of and no gap for wind to whistle down. 


Also need to check his sizing as 100/100 isn’t a standard size - 100/65 or 100/140 are and you may find they are in stock and cheaper to either stack 2, or use the 215 on its side which is normally more than adequate unless there is a point load. 
 

 

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On 02/06/2022 at 09:32, lstevensuk said:

H- My SE has specified for every door cut-out 2 x 100x100 concrete lintels. This seems a strange size and probably quite difficult to obtain and fit in. Is this normal?

 

Also an example of where I'm putting one. They are cavity walls (if you count 20mm as a cavity!)

 

95628266_BedroomLintel.png.9186a04d48a7784d3dd29787e623ca50.png

 

 

 

Office.thumb.jpg.0822310147bddcbc5068c0fc1e77a3c4.jpg

A few random thoughts.

 

I'll start with what may be going through you SE's mind and their thought process.

 

The 100 x 100 lintels tend more often to be what we call non composite lintels. In other words they act like steel beams say that "stand alone" and don't rely on having masonry above that interacts with the lintel / beam to create an arching / deeper beam effect. The 65mm deep lintels work in a different way, often compositely and they need to interact with the masonry above. In other words they are two different animals... but look very much the same.

 

Now if you don't have say 4 -5 courses of brick above the lintel then you often need a non composite lintel. Also, on alteration work no matter how well you repoint the gap over the lintel you'll never get the same "bedding effect" that you get when you are laying the wall for the first time. You new mortar will shrink away so the brick above won't interact with the lintel to develop the composite action. In other words you can rule out a composite lintel on most alteration work. The difference in load bearing capacity is a lot so don't get caught out.

 

You SE has probably also thought about how you prop the wall when you are doing the work and how much space you have to do this.

 

They have probably also thought about what is above.. are there point loads from floor joists, maybe other stuff above, a door over lapping the opening, all sorts of permutations.. and that again rules out a composite lintel.. hence the 100 x 100 that is a non composite lintel. The 100 depth is say enough to carry the final loads but shallow enough for you to prop it?

 

Before you go ahead mull this over. Be very careful about putting in any lintel orientated in a different direction from the manufacture's intention.. trouble ahead!

 

Your weird 20mm cavity!

 

What you probably have there is what we call a collar jointed wall. The two leaves are tied together with brick ties at much closer spacing than you have in a normal cavity wall and the gap between the leaves is filled with mortar... the gap is usually 10 - 20mm to allow for variations in the brick widths.. hence the 20mm you are observing.  This allows you to design the wall using it's full thickness so you get more bang for your buck.

 

In summary it looks like your SE has put a bit of thought into this.

 

I would lift the phone to your SE before you start deviating from the design.

 

 

 

 

 

 

 

 

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