Shed revamp

I am seeking your advice.

I have purchased a house in Goulburn, NSW, and there is an existing 9m x 6m zincalume and colourbond shed in the yard. The floor is two-thirds cracked and stained concrete, and one third dirt. I intend to cover the existing floor with new concrete and paint it with an epoxy paint for easy clean-up and aesthetic value.

For year-round comfort I intend to insulate the shed with batts or an Aircell type product on the walls and roof, then line them with either Gyprock or 16-18mm plywood sheeting. I also intend to fit a split system air conditioner (I've waited thirty years for this!). There are two cantilever style doors on one long side and I intend to remove one and re-skin those panels. The remaining door will be removed and fitted with a barn type door, allowing access into the shed for a box trailer.

So to my questions:

Should I fit a vapour barrier between the metal and the insulation?

Would the fitment of Aircell over or under an insulation batt give more effective protection from cold and heat?

What is the highest rating for insulation batts available in Australia? I have seen batts with values of R30 and higher fitted to North American houses and sheds. Do we rate our batts on a different scale here?

Is there any reason to use Gyprock instead of plywood, or vice versa?

Has anyone had experience with spray foam insulation in a house or shed, or is it cost prohibitive?

Your advice will be greatly appreciated.

Thanks

Slopey.

Firstly welcome to the forum.

I'll answer the questions I can answer - I did a similar thing to what you are thinking about.

I have a 42 m² shed- 1/3rd of my the walls are ; Trimdeck - rock wool - minor, one 6th is Trimdeck - Aircell - Gyprock, and one half is Trimdeck (over timber framed asbestos)- air cell - Gyprock, and Sisalation under the roof.

To see what and how I did it you might want want to look at my shed fit
https://www.woodworkforums.com/f245/s...-perth-127060/
and more here
https://www.woodworkforums.com/f245/b...ed-fit-134670/

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Originally Posted by slopey

Should I fit a vapour barrier between the metal and the insulation?

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I didn't and have had no probs.

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Would the fitment of Aircell over or under an insulation batt give more effective protection from cold and heat?
As long as you leave a gap between the the two Aircell must have a gap to work properly otherwise it's wasted.

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What is the highest rating for insulation batts available in Australia? I have seen batts with values of R30 and higher fitted to North American houses and sheds. Do we rate our batts on a different scale here

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I am a personal friend of one of two of the only accredited insulation testers in Australia and he reckons that most insulation ratings (especially imported stuff) are not worth the paper they are written on.
One thing to be aware of is that just doubling the insulation does not necessarily double the improvement in temperature. There are so many other things that affect temp control, like leaks (your cantilever doors for instance) that should be attended to along with a basic insulation installation.

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Is there any reason to use Gyprock instead of plywood, or vice versa?

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Gyprock is cheap and is a great insulator.
Plywood is a bit more exp but it does enable stuff to be hung directly onto it.
I used gyprock with 600 mm spacing vertical bracing and just marked where all braces were so I could attached "stuff" to the bracing.
I also put a couple of 8 x 4' sheets of plywood over the gyprock on the wall in a corner to hang garden tools.It was just easier to do this than work out a way of matching the ply to the gyprock.
If I had the $ and I was to do it all again I would use Miniorb for all the wall cladding - it looks great, non-flammable, "stuff" can be hung on it directly and it is surprisingly quiet.

I put a lot of effort into sealing all the gaps and have a 2.2kW in wall air-con and it does a fair job on it's "medium" setting to hold the room temp at 23/24º when it is 35º outside. When it is 40º outside I have to have it running on "high" to maintain the 23/24º but I usually just let it go up a few degrees.

The killer for Aircon is and serious dust extraction since the extractor is best located outside the shed. I tend to try and perform dusty tasks in the morning when it is cool and the do other stuff after that.

What are you thinking about for dust extraction - we have a useful Dust forum on this topic you may want to look at before commenting on this.
DUST EXTRACTION

Greetings Slopey!! :2tsup::2tsup::2tsup:
This is the best shed on the internet, a veritable fountain of useful information,
such as that given by our friend BobL.

Good size shed you have and the modifications you have planned are certainly worthwhile.
I have never lined or insulated a shed But often wish I had.

or what it is worth my brother has a 7x7 Titan shed that has a high roof. He used aircell
insulation in the roof only and the temperature difference is quite noticeable.

I agree with Bob on the cost factor when it comes to Gyprock. If you mar your studs on the
floor it becomes no problem to attach some type of timber for hanging tools and so on.

You can - or could - get thicker Gyprock and this may help that little extra with insulation and sound proofing.

Have fun!!!

Good Morning Slopey

Wellcome to the Forum.

Fully agree with Bob and Artme's comments.

On insulation, to convert from the American rating system divide by 5.67 to get the metric equivalent.
eg American R = 30 divided by 5.67 gives metric R = 5.3

There is a lot of hard science, good reasoning and recommended R-values on this site.
Your Home Technical Manual - 4.7 Insulation
The recommendations were done 5-6 years ago, so were based on energy costs then prevailing. Perhaps a little higher R-rating is now advisable, a lot higher if you are pessimistic about future energy costs.

I failed to get my concrete floor flat and level 20 years ago. That was and is a serious mistake.



Fair Winds

Graeme

Hi Slopey,

Sounds like a great space you've got there! If you want a good introduction to insulation and related topics for Australian conditions the book 'Cool House, Warm House' by Nick Hollo is very good.

R value insulation ratings can lead us to believe that the more R the better but it is not necessarily the case. Heat can be conducted, convected or radiated and different arrangements of insulation will be better at combatting which ever of these is your greatest problem. You can easily make a house or shed more uncomfortable by insulating it in the wrong way, not effectively keeping the heat out but very effectively trapping it inside!

I'm sure you'll be able to sort it out and there are members here far more experienced than me who I am sure will be able point you in the right direction.

Cheers