How to insulate walls for an existing st... - Page 2

mshed65

Hi all.

I realize this topic has been raised a number of times and i have looked at previous conversations but retrofit style projects usually have unique requirements/nuances that suggest differing approaches. I have a 9x6m steel framed shed (Stramit, portal frames at 3m crs with 64mm top hat purlins and girts at generally 1400mm crs) that was constructed on the land i purchased. I think it is circa 20 - 25yrs old. I am now looking to line some of the walls to allow building benches/shelves etc. I had built some benches against a shed wall previously by simply fixing timber plates to the shed walls - screwed from the outside through the wall sheeting - but this time would like to line the walls likely with plywood (painted) for a better look and the ability to fix anywhere to the internal walls in the future. Fixing the ply sheets to the inside will provide a 64mm air gap (top hat purlin depth) so a bit of insulation but i am looking to get a bit more insulation if possible - primarily against heat as Brisbane summer is extremely hot in there!!

Being a standard steel framed shed construction, it does not have sisalation/wall wrap between the girts and wall sheeting so simply placing batts between the airgap (external sheet metal wall and internal ply lining) would provide insulation but also be subject to condensation from the inside skin of the wall sheeting wetting the batts so possible mould problem down the track? I have a roll of Anticon (Bradford roof blanket product, glasswool adhered to reflective foil) left over from my last reno and wonder if this could be used in any way. My current thoughts on possible solutions are as follows:

1. Cut pieces of coreflute and place between girts against wall sheeting, then install insulation batts prior to ply sheeting.

2. Fix Ametalin reflective wall insulation to inside of girts and ply sheeting directly over. Should be slightly better than air gap alone? Normally for new build, reflective side is internal and vapour barrier external beneath cladding but here which side for reflective foil given that i want to keep heat from outside coming in? Will get condensation in air gap but not really a concern.

3. Use the Anticon i have for as far as it goes with reflective foil outside against the wall sheeting? Use 1 or 2 above for remainder?

Some may suggest using Foilboard which i will use for the ceiling if i decide to insulate it. I haven't considered it for the walls as this then does not allow fixing of future items anywhere (girt locations only) nor is it particularly great to fix ply sheets over, whether 20 or 25mm thickness foilboard.