Steel Corner Post insulation

[Ay8452]

Hi folks,

 

I have a steel 200 x 200 corner post as part of a corner set of sliding doors. Had a read of very useful previous threads 

 

Looking to insulate this and was going to do the following

 

1 - on the external two sides place PIR board (any specific type I should use as it may be exposed to the elements?) or EPS board

2 - Internal two sides place vertical strips of aerogyl as space is a premium here (the corner post is inline with the the inner leaf for one wall and then cavity centre for the other wall, therefore I have more space externally hence use of PIR board/EPS in that location)

3 - wrap the post in a VCL (any recommendation on a brand/type?)

4 - clad the steel post with timber

5 - Fit sliding doors/Alum cladding around post

 

Does this sound about right? Should I just stick to one type of insulation and sue aerogel?

 

See pic below of my structural drawings

 

 

Then added my insulation below (orange being EPS/PIR) and green being aerogyl.

 

 

 

[Nickfromwales]

Use Marmox or Jackoboard (XPS), and you won’t need a VCL. Have the cuts butted up tight and use CT1 to bond the boards to the steel, using continuous lines of it to stave off convection airflow between the steel and the boards.

 

Aerogel vs XPS = near zero real life differences tbh, but if you can use the thickest board you can then every extra mm will be a bonus.

 

I’d avoid PIR as you can’t fix much to it without it delaminating. 

[ETC]

Will the thermal loss be any greater than through the adjoining window?

[Gus Potter]

On 13/04/2025 at 18:25, ETC said:

Will the thermal loss be any greater than through the adjoining window?

This is pragmatism and actually very clever.

[JamieB1917]

@Ay8452 Did you manage to sort this in the end? I have a similar dilema. 

 

Also can i ask how your steel was fixed? Was it to the concrete foundation or on the blockwork at DPC level?

 

Thanks

Edited October 8 by Nickfromwales
Name tagged

[Nickfromwales]

@JamieB1917

 

You can thermally decouple the steel from a cold foundation / support by using any of many different, suitable products out there, capable of load bearing. 
 

Most recently I have used Bosig Phonotherm for this. Very robust, and very simple to cut / shape.

 

[saveasteading]

50 minutes ago, Nickfromwales said:

thermally decouple the steel from a cold foundation

I hadn't heard of this product so thanks @Nickfromwales.  BUT I can't see any mention of it used in supporting a post, or of its bearing capacity so I doubt this is suitable for that They say Structural a lot, but without numbers.

They also stay quiet about the insulation numbers.

If that post is simply holding the side of a wall or window then OK, but not to take a vertical load without some proof.

 

OK found it. 7,000 kPa at 10% compression...... but we wouldn't want it compressing under a post and it is made of foam, however dense.

No mention of the strength before compression which again suggests it is for light structural use where the forces are small.

 

That is 7,000 kN/m2 or 1/3 of concrete strength so quite impressive... so not suitable for heavy structures.

 

And the insulation level is OK too considering the density.  Marmox is a bit better.

 

Back to the question, even though it has probably all been built by now. 

Forget about the base to concrete. Stuff the open web with PIR, then board over as above.