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Insulation suggestion for stainless steel shed

Hi everyone,

We are in the process of getting our steel shed built, and was advised by the tradies that we should be insulating the whole shed, including the recreational room.

They recommended the reflective thermal insulation for the roof and just use the plasterboard for the wall for recreational room.

But different people have given us different advices, so am confused which insulation to use.

I have done some research online and the more I dig, the more confused I became.

I was told the higher the thermal M2k/W, the better.

Is that correct?

The thermal insulation productive we are looking at has a Material Thermal Resistance of 0.20 (M2K/W).

Would that be good enough? How many degrees can it reduce the heat of the shed?

We live in Far North Queensland, so heat will be an issue in Summer.

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StevieB

Hi @Sunda.

Let me tag @Adam_W, @DIYgals, @Itai and @TheSaltyreefer to share their thoughts and kick off this discussion. Our resident D.I.Y. expert @MitchellMc will also be happy to help when he's back on the site on Friday.

Stevie

Itai

Hi @Sunda

We have used plasterboard and sicilation paper (foil) for our cubby. It's definitely an improvement, but I doubt it will do much in summer. Just some light protection.

For something a bit more serious, I'd probably be looking to put some foam board in the walls between the plaster and metal walls:

https://www.bunnings.com.au/bastion-1200-x-600-x-30mm-xps-multi-use-insulation-foam-board_p0139535

Or you could go all the way and use insulation batts like earthwool.

Depends on your budget.

I'm not much help in calculating ideal cooling values, but you'd probably want an R2.5 or higher if it gets really hot. But speak to an insulation expert up there.

Something to keep in mind. Insulation doesn't stop heat or cold, it slows the exchange down. Usually enough that you'll never get the full day time heat.

But if it's hot at night and the day there, it will still get hot in the shed.

So consider putting in a wall mounted or portable aircon.

Regards

Itai

MitchellMc

Hi @Sunda,

Commonly, the insulation rating of a product is denoted in R-Value. Our Ametalin 1200mm x 60m SilverSark HD Reflective Roof and Wall Insulation has an R-Value of 1.52 on a roof during Summer. Do you have an R-Value for the product you were looking at instead of the Material Thermal Resistance? If so, it would be much easier for us to compare.

Foils generally offer in the R1.0-2.0 range, which isn't much in extreme heat. An insulation batt provides up to around R2.7.

Regardless of the product you use, I believe it would be near impossible to give you an approximation of the degrees it will lower the shed. Without using some type of air-conditioning, the temperature inside might be slightly more bearable insulated with foil than outside.

Please let me know if you have any questions.

Mitchell

Sunda

Thank you for your clarification, Mitchell.

The one we are looking is GI Building Sciences 10mm 1.35 x 22.25m with 150mm Flap 30m² Reflecta Guard V2 - Bunnings Australia

Based on their brochure, does that mean the RT is R3.2 (downwards) for summer?

Is that the same as R value?

I do not quite understand the difference between summer downwards and upwards.

Also, the test looked like it was conducted on a flat metal roof. Would that be any difference if it is a high pitched roof?

Our shed design has a high pitched roof.

Would this product be any good?

Thank you for your help, Mitchell.

Sunda

Thank you for your advise, Itai.

I really appreciate it.

Our tradies have recommended the GI Building Science product, as it would be quicker for them to install.

So will check with Mitchell to see if that is a good option.

You have a good weekend.

MitchellMc

@Sunda,

'Up' R values describe resistance to heat flow in an upwards direction (sometimes known as 'winter' R values). 'Down' R values describe resistance to heat flow in a downwards direction (sometimes known as 'summer' R values). They are just different ways of denoting that one value is for Summer and one for Winter. The RT is the R-value, so this product has great insulation properties compared to standard Glasswool products and fantastic insulations values compared to standard foil sarking.

You should see similar results on a pitched roof versus a flat roof.

If your builders are happy with the GI Building science product, I'd suggest that will be one of your best options.

Mitchell

Sunda

Thank you for your advise, Mitchell.

Really appreciate it.

MitchellMc

Keep us updated on your project @Sunda, and please reach out if you need further assistance.

Mitchell

DIYgals

Hi @Sunda ,

We are in the middle of a similar project atm.

On the walls between the steel sheets and plaster board we have uses Earthwool and on the ceiling a product called Air-Cell and also have installed an air-conditioner.

We haven't experienced a summer yet, so it will be interesting to see how it goes.

Good luck with the project!

Sunda

Thank you DIYgals!

I really appreciate it.

Am wondering if would mind advising the size of your shed and how many KW of air conditioner did you install?

We are looking at installing an air conditioner as well.

DIYgals

@Sunda

No problems!

The space we are cooling is approx 40m2 and have chosen a 6.5KW unit. We took into account location, aspect and pitch as well as the colour of the sheets and thought it was a good idea to choose a larger unit.

We used this guide : Choice AC Guide

EricL

Hello @Sunda

It's great that you've received fantastic advice from @DIYgals. I just wanted to add a few tips to the suggestions that have already been made. Use light coloured paint for both the roof and outside walls. Lighter colours reflect heat versus dark colours that absorb heat. I recommend using Dynabreeze 450mm Silver Industrial Floor Fan or an equivalent to get good air circulation in your shed. This will uniformly distribute the cold air and saves your AC unit from working too hard.

It sounds like a fantastic project. Any updates you can provide while it's being built would be much appreciated.

If you need more advice or information, please let us know.

Eric

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