Insulated Catnic - illusion?

[curlewhouse]

So looking at the plans and I'm supposed to buy insulated catnics - but looking at them the insulation makes no sense as they are one giant cold bridge. The amount of heat transfer through the air in their cavity would be so minor compared to that whacking great bridge of metal that I'm not clear if it is simply an attempt at blagging. Am I missing something?  

Edited May 4, 2017 by curlewhouse

[PeterW]

I don't think you can buy uninsulated lintels now ..! Yes it is a cold bridge but unless you want the joy of building two separate skins and managing the lintels and the insulation and openings they are no worse than the big expanse of glass below the lintel..!

[Declan52]

You can use a single skin lintel on the outside for the bricks and a concrete head on the inside. Then bring whatever you have in the cavity down to fill the gap. 

[DNA]

Hi Declan52. I never thought of that. Has anyone done any cost comparisions between cavity lintels and the option of using an external galv lintel and a concrete internal one?

 

[PeterW]

Concrete internal lintels start to get expensive and unwieldy at anything above 1700mm as they are invariably 215 x 100mm and that gives 27kn loading. 

 

As an example using 1800mm lintels

 

Catnic single (£32) Naylor Concrete (£69) £101

 

catnic CG90 £43

 

It does make sense if you go over a 200mm cavity as the pricing goes silly for cavity lintels at anything above 125mm

 

 

 

 

[DNA]

Good point Peter. There was an outside chance there of my lintel schedule cost dropping a bit!

[Declan52]

20 minutes ago, PeterW said:

Concrete internal lintels start to get expensive and unwieldy at anything above 1700mm as they are invariably 215 x 100mm and that gives 27kn loading. 

 

As an example using 1800mm lintels

 

Catnic single (£32) Naylor Concrete (£69) £101

 

catnic CG90 £43

 

It does make sense if you go over a 200mm cavity as the pricing goes silly for cavity lintels at anything above 125mm

 

 

 

 

Wouldn't need a 9 inch head for that span, 6inch would be fine. I have 2 concrete prestressed heads at 4.4m long over my patio doors. They took some handling!!! 2 Brickies will easily lift heads up to 2.5m and if they are bigger you can always use a digger or telehandler to sling them in.

Edited May 4, 2017 by Declan52

[PeterW]

Even a 6" head is £43 so pricewise you are more than double. Difference is you can pick an 1800 catnic up with one hand ..!

[Oz07]

I got 150mm cavity lintels cheap enough. There not so unusual now

[PeterW]

My 150s came direct from Catnic so on a 4 day turnaround - most BMs have 100s on same day in stock which isn't a huge delay but you need to bear it in mind. 

 

I used Condell online and they beat everyone's prices

[Mr Punter]

I tried to spec the Keystone Hi Therm lintels, which have a thermal break and a much better Psi value.  Lead times made them impractical though.

[Lin]

We are converting a building that has catnic lintel already in situ over a wide opening that will become bifold doors

 

The lintel is uninsulated.

 

Is there much point trying to squirt insulating  foam through the holes (there is  a regular pattern of holes on inner side of the lintel) to try to fill it up the hollow with an insulator ??

 

Thanks

Edited January 28, 2018 by Lin

[Nickfromwales]

Yes, plenty of merit to that solution. Just be sure not to allow the foam to expand beyond the end of the lintel. 

[PeterW]

2 hours ago, Nickfromwales said:

Yes, plenty of merit to that solution. Just be sure not to allow the foam to expand beyond the end of the lintel. 

 

+1 to that. Squirt the inside with a bit of water at each end to make it go off quicker and then fill the last 6" of each side. Let it go off for a few hours then go back and fill the centre section up through all the holes.

 

Strangely satisfying, but don't stand under it once you've done it as you will get it in your hair... ask me how I know !

[MikeGrahamT21]

Check IG lintels out too, even their standard lintels have a much lower PSI value than catnic if I remember right, and they're cheaper!