Injecting spray insulation into SHS

[Tony K]

Evening all.

I have a steel goalpost frame with 2.5m SHS columns at either end. The columns sit in the blockwork cavity, and I would like to fill them with spray insulation. I can only access the top part of the columns now. 

Will I be able to fill an entire SHS column from just one drilled hole at the top end, or will the spray insulation fill an area near the hole too quickly for that?

Cheers

[Onoff]

Is this then going to be over insulated? I foam filled some 100x100x6 gate posts and they sweated like a bastard on the outside. Literally condensation running down the outside. I filled from both ends.

 

They were freestanding outside though.

 

 

[Tony K]

15 minutes ago, Onoff said:

Is this then going to be over insulated? I foam filled some 100x100x6 gate posts and they sweated like a bastard on the outside. Literally condensation running down the outside. I filled from both ends.

 

They were freestanding outside though.

 

 

 

No I don't think I'm at risk of overinsulating. The columns are in the cavity (mostly). 

 

When filling from both ends did you use spray insulation, do you think you filled the whole column, and do you reckon you could've filled the whole thing from just one point of access? 

[SuperJohnG]

1 hour ago, Tony K said:

Evening all.

I have a steel goalpost frame with 2.5m SHS columns at either end. The columns sit in the blockwork cavity, and I would like to fill them with spray insulation. I can only access the top part of the columns now. 

Will I be able to fill an entire SHS column from just one drilled hole at the top end, or will the spray insulation fill an area near the hole too quickly for that?

Cheers

Arguably wont do anything. The heat will pass directly around the section. The only thing that insulation will stop is radiating heat travelling from one face to the together which I presume would be negligible compared with the thermal flow in the steel. Best to insulate it externally if you can. 

Edited March 7, 2022 by SuperJohnG

[Onoff]

16 minutes ago, Tony K said:

 

No I don't think I'm at risk of overinsulating. The columns are in the cavity (mostly). 

 

When filling from both ends did you use spray insulation, do you think you filled the whole column, and do you reckon you could've filled the whole thing from just one point of access? 

 

I used a foam gun and I reckon it squirted 4 or 5' up the box from each end so it certainly filled it. You can do it with an extension tube. I could see up both ends of my box section.

[Tony K]

14 minutes ago, SuperJohnG said:

Arguably wont do anything. The heat will pass directly around the section. The only thing that insulation will stop is radiating heat travelling from one face to the together which I presume would be negligible compared with the thermal flow in the steel. Best to insulate it externally if you can. 

 

There is one column in particular I need to address. To accommodate an exposed brickwork inside to outside feature wall which needed a vertical insulated dpc, I have had to place the shs column so that it is partially in the cavity and partiality sitting on the outside wall, exposed to the elements. 

[Tony K]

1 minute ago, Onoff said:

 

I used a foam gun and I reckon it squirted 4 or 5' up the box from each end so it certainly filled it. You can do it with an extension tube. I could see up both ends of my box section.

 

Understood, thanks. 

[Onoff]

Next time I'd just empty a can of ACF-50 into the box section then paint and insulate the outside.