Split lintels?

[SBMS]

We’re building brick and block with a 200mm cavity. EPS beads blown in. Our engineer specified (notionally) a one piece lintel. Builder has had lintel company let us down and now those lintels are a couple of weeks out. Floor Is ready to go on so he is suggesting we do steel split lintels. Is there anything anyone would advise as to why not to go this direction?

[Nickfromwales]

https://condell-ltd.com/catnic-standard-duty-thermally-broken-cavity-wall-lintel-ts150-100-750mm?gad_source=1&gclid=Cj0KCQjw1um-BhDtARIsABjU5x6w0qbQNEyACFR81sLEzaErCAncCfhYPntTGQKbqppQ7jsLiWdxmjoaAmBoEALw_wcB

 

Suggest these maybe?

[SBMS]

  On 19/03/2025 at 21:47, Nickfromwales said:

https://condell-ltd.com/catnic-standard-duty-thermally-broken-cavity-wall-lintel-ts150-100-750mm?gad_source=1&gclid=Cj0KCQjw1um-BhDtARIsABjU5x6w0qbQNEyACFR81sLEzaErCAncCfhYPntTGQKbqppQ7jsLiWdxmjoaAmBoEALw_wcB

 

Suggest these maybe?

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Thanks - are these recommended/needed (with the polystyrene insulation in middle) if we are doing beads? Or is the polystyrene on the product image just an example?

[Nickfromwales]

  On 19/03/2025 at 21:49, SBMS said:

Thanks - are these recommended/needed (with the polystyrene insulation in middle) if we are doing beads? Or is the polystyrene on the product image just an example?

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You may need to close the cavity off I expect, somehow, but as I don't have sectional drawings to comment from these are generalised bits of info from a man you've never met before on the internet.  

 

With blown full fill bonded beads, I'd have thought these would round things off nicely. Otherwise where do the beads stop during installation?

[Nickfromwales]

  On 19/03/2025 at 21:49, SBMS said:

Thanks - are these recommended/needed (with the polystyrene insulation in middle) if we are doing beads? Or is the polystyrene on the product image just an example?

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You may need to close the cavity off I expect, somehow, but as I don't have sectional drawings to comment from these are generalised bits of info from a man you've never met before on the internet.  

 

With blown full fill bonded beads, I'd have thought these would round things off nicely. Otherwise where do the beads stop during installation?

 

As in, they'd just spew out?

[SBMS]

  On 19/03/2025 at 21:55, Nickfromwales said:

You may need to close the cavity off I expect, somehow, but as I don't have sectional drawings to comment from these are generalised bits of info from a man you've never met before on the internet.  

 

With blown full fill bonded beads, I'd have thought these would round things off nicely. Otherwise where do the beads stop during installation?

 

As in, they'd just spew out?

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The cavity would be need to be closed at the head of the window - as with the sides. I assume there will still be a tray above but I assume the beads will get ‘between’ the tray and the head closer?

 

Best advice comes from anonymous people on the internet!! 😂

[Tony L]

The Catnic split lintels look good to me.  I know next to nothing, by the way, so don't take this as advice.

 

I'm just wondering how these compare, performance wise, with the (presumably cheaper) option of two separate steel reinforced concrete lintels.

 

Edited March 19 by Tony L

[SBMS]

  On 19/03/2025 at 22:09, Tony L said:

The Catnic split lintels look good to me.  I know next to nothing, by the way, so don't take this as advice.

 

I'm just wondering how these compare (performance wise) with the (presumably cheaper option) of two separate steel reinforced concrete lintels.

 

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I think he’s priced that split lintels will be cheaper and the beads will provide the insulation between the two leafs?

 

I’ve tried to draw how I think itll work

- does this work with getting the beads between the cavity tray and the cavity closer?

 

pink is outer/inner leaf

grey is beads

green are box and inner lintels

orange is cavity closer

 

[Nickfromwales]

  On 19/03/2025 at 22:04, SBMS said:

The cavity would be need to be closed at the head of the window - as with the sides.

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Very differently from the sides, as the head needs to manage and direct any falling water to the internal face of the façade and outwards through, for eg, weep joints.

[Nickfromwales]

  On 19/03/2025 at 22:12, SBMS said:

pink is outer/inner leaf

grey is beads

green are box and inner lintels

orange is cavity closer

 

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And the blue?   

[Tony L]

May I just check, the tray (blue line above) goes beneath the lintel, as shown - I think it might go above.  & I'll just remind you, I know next to nothing.

[torre]

NHBC have good examples of split lintel details (fig 21 & 22).

 

 You'd use the same cavity closer at the head as whatever you've used at the sides.

 

If you're concerned about ensuring beads can fill the gap later between closer and tray you could fit something full fill like Isover 32 now, cut to the angle before putting the tray over.

 

(We used concrete lintels for some of our inners as it's cheap and airtight, some of the metal have holes)

[SBMS]

  On 19/03/2025 at 22:14, Nickfromwales said:

And the blue?   

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Sorry forgot to say that’s the cavity tray

[SBMS]

  On 19/03/2025 at 22:16, Tony L said:

May I just check, the tray (blue line above) goes beneath the lintel, as shown - I think it might go above.  & I'll just remind you, I know next to nothing.

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Yes sorry it’s my fat fingers drawing on an iPhone 😂 the nhbc detail at least marries up with what I was thinking and what the builder explained to me. My main question is that a split lintel seems much better for thermal bridging. Is it just labour and cost as to why people use a One piece?

[Nickfromwales]

  On 19/03/2025 at 22:28, SBMS said:

Sorry forgot to say that’s the cavity tray

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We'll learn to forgive over time.  

  On 19/03/2025 at 22:31, SBMS said:

Is it just labour and cost as to why people use a One piece?

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But is it not easier to just use the thermally broken one?

[SBMS]

  On 19/03/2025 at 22:13, Nickfromwales said:

Very differently from the sides, as the head needs to manage and direct any falling water to the internal face of the façade and outwards through, for eg, weep joints.

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I think this is what the cavity tray is for and then directs out to weep holes?? I think the closer sits below all this but I’m guessing to be honest. I think the nhbc detail Shows this. 
 

one thing I am trying to Work out as I cant

think in 3d… Would pumped beads get to

the cavity below the tray indicated below??

 

[SBMS]

  On 19/03/2025 at 22:34, Nickfromwales said:

We'll learn to forgive over time.  

But is it not easier to just use the thermally broken one?

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Probably! To me the thermally broken one is just a split lintel but they’ve supplied the insulation?? 

[Nickfromwales]

  On 19/03/2025 at 22:35, SBMS said:

Probably! To me the thermally broken one is just a split lintel but they’ve supplied the insulation?? 

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And done away with the need for the tray !! The EPS is bonded to the front tray profile so that manages the runoff  

[Tony L]

  On 19/03/2025 at 22:34, Nickfromwales said:

But is it not easier to just use the thermally broken one?

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I'm just guessing, but I should think people use the other Catnic lintels - the kind with a thermal bridge, because they're cheaper.

[SBMS]

  On 19/03/2025 at 22:36, Nickfromwales said:

And done away with the need for the tray !! The EPS is bonded to the front tray profile so that manages the runoff  

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Ah okay.. I thought all lintels needed a tray above no matter what.. The one piece that was specified (it was a catnic) still had a tray specified by architect.. I might show that to builder 

Edited March 19 by SBMS

[Tony L]

  On 19/03/2025 at 22:41, SBMS said:

 I thought all lintels needed a tray above no matter what.. 

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I still think that.  + a tray costs next to nothing, so why wouldn't you?

[Nickfromwales]

  On 19/03/2025 at 22:48, Tony L said:

 

I still think that.  + a tray costs next to nothing, so why wouldn't you?

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I also may be wrong, lets stay up and fight 👍 I've just never seen two exposed edges from outside over an opening, only ever the one, so assume the thermally broken one is a one-stop, kosher affair?

[Nickfromwales]

  On 19/03/2025 at 22:48, Tony L said:

 

I still think that.  + a tray costs next to nothing, so why wouldn't you?

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Because it would stop the beads fully filling maybe?

[SBMS]

  On 19/03/2025 at 22:53, Nickfromwales said:

Because it would stop the beads fully filling maybe?

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 I wondered about that but there shouldn’t be anything stopping them flowing around and under the tray?

 

I also wonder if these in 200mm are what he has struggled to get. Most places online seem to only stock up to 165mm cavity version. Maybe 200mm are special order?

[Nickfromwales]

  On 19/03/2025 at 22:56, SBMS said:

 I wondered about that but there shouldn’t be anything stopping them flowing around and under the tray?

 

I also wonder if these in 200mm are what he has struggled to get. Most places online seem to only stock up to 165mm cavity version. Maybe 200mm are special order?

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I was special order and made it to 51! Anything is possible