How to insulate steel frame walls with brick veneer?

Question

Hi,

I'm looking for advice on how to insulate walls with steel frames + brick veneers. I can find videos and tutorials on homes with timber frames but not steel. I've just removed all the plasterboard from the walls, leaving a 60mm gap from the cornice, as I don't want to redo them even though it might give a better finish.

The frames are 75mm thick with 450mm spacing. There is a 30mm air void gap from the frame to the brick walls for the external-facing walls. Do I get polypropylene string/straping to put on the back of the steel frame as a brace, then line the inside of the frame with sarking such as Ametalin VapourTech Brane VHP Vapour Permeable Wall Insulation?

My question to add to this would be how do I attach the strapping and vapour barrier (if they are the correct materials to start with) to the metal frame? Do I use metal tapping screws (as timber frames would just get stapled down)? Then, for the actual insulation, would I just cut the R2 75mm EcoWool Wall Batts to size and slot them in?  Once the wall batts are in, just install the new plasterboard?

Last question would be how do I remove all the Plasterboard glue adhesive stuck on the metal frames? Chisel and hammer? Multi tool with scraper? They're stuck on quite well. Just cleaning everything up before I start insulating.

Thanks for the help, hope I gave enough context.

Dave-1 · Answer

Good Evening @Toz

I think you will have a bit of a sweaty job ahead but definitely doable :)

I was thinking of the string with the Ametalin VapourTech Brane VHP Vapour Permeable Wall Insulation that @EricL  has mentioned (or something similar)

You could tie the string off end to end of the wall to start with and then sandwich the vapourtech between the string and the meatal, then Id use the same glue that you use for the plaster to secure it. Then once dry, remove the string (or leave it) and do the two end parts, you could pull the vapourtech against the ends by stitching a loop of the string through near the points you will glue and gently pulling them tight.

I would check to see if the plaster glue (goop as I call it in my head) reacts with the vapourtech material. @EricL or @JacobZ would know more product wise on that. (id just put some goop on the material and wait till the weekend to see if its shrunk or rippled the material :) )

The insulation I would go with what @EricL has suggested and not solidly push the insulation into the frame. And I have used a chisel (old one or cheap one) and hammer to sharply strike the edge of the old glue to remove it. It came away pretty easily)

Extra things I did for my retrofit of the garage was to add drawstring to potential cable runs down the track if needed, costs nothing to have a string and a stick tied to the end sitting in the wall to the top of the wall type deal. Doesn't have to be used but its available. So think audio, surround sound, workshop power points, network cabling, HDMI cabling. Gas points for cold winters.

Garage lining for stud walls stage 1

Garage lining for stud walls stage 2 (Cornice and skirting boards)

Would love to see your project when completed especially with a bunch of photos of how you did it :)

Dave

EricL · Answer

Hello @Toz

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about insulating your walls.

I'll start with the Ametalin VapourTech Brane VHP Vapour Permeable Wall Insulation. The Brane VHP wraps the external side of the wall studs, before the external cladding goes on. This type of vapour-permeable wall wrap acts as the weather-resistive layer, helping prevent wind-driven rain and air movement entering the wall while allowing water vapour within the wall assembly to dry outward. Comparable Australian high-permeance wall-wrap installation guidance specifically shows the membrane being unrolled and fixed over the outside face of the timber studs, but in your case, it would have been over the steel studs. I'll have to refer this to our more experienced members as to what they would recommend.

In regard to the polypropylene string/strapping, the offered suggestion was to use a self-tapping steel screw with a washer. Again, this was supposed to be done on the outside part of the frame. One possible option would be to wrap the strap on the steel stud so that it sits on the outside and then the end of the strap can be secured with a screw to prevent it from unravelling.

As to the R2 70mm EcoWool Wall Batts a 5mm compression of insulation batts is generally acceptable and shouldn’t meaningfully affect their thermal performance. The important thing is to avoid heavy compression. If the batt is substantially thicker than the steel-stud cavity, it’s better to use a batt designed for that cavity depth rather than forcing it in.

I suggest using a sharp chisel and hammer to lift and remove the old adhesive stuck to the steel frame. Please remember not to damage the steel frame and to hit only the glue in order to lift it up.

Let me call on our experienced members @Nailbag, @DIY4Knuckleheds, @Adam_W, @TedBear and @Dave-1 for their recommendations.

Please remember to wear personal protection such as appropriate clothing, closed toe shoes, gloves, goggles and a mask.

If you need further assistance, please let us know.

Eric