Thread: Hot Shed- summers coming

Have a look at post #9 in this thread. The idea of using the water collected from the roof to cool the roof seems really sensible.

As important as insulation is airflow. Do make sure you can get the prevailing breeze through the shed. Also consider putting a whirlygig extractor on the roof. Getting hot air out pf the shed is important to making a comfortable shed

Biggie,

I am a shed builder and your best product is your foil based building blanket, Bradfords Anticon 55 or 75mm or equivalent by another manufacturer. Steer away from gimmicky "Air" or Bubble type insulation. If you are going to take the roof off you may as well do it properly.

You will need to take the roof off, and probably the gutters as well. Lay your blanket over 1.25mm Insulmesh support mesh. The blanket should be laid shiny side into the shed as you do not want any fibres inside. The blanket is laid over the roof purlins. As a natural consequence it is compressed over the roof purlins where it is screwed off and loses some efficiency, but short of creating a cavity ceiling it is still the best option. You should be able to cut it pretty much to length. You may have to back out the top row of wall teks to allow you to push back the wall sheet a little to pin the roof insulation before screwing off.

This product used like this is basically a thermal break and bulk wool insulation and sisalation. If you are lining the shed internally it would probably be easier to use batts as these can be cut between the wall girts and secured when the internal cladding is used. Eitherway your building blanket and foil to the outside of the wall and roof wil be a good start, and if you ever do enclose down the way you can chuck some more batts in the walls to get even better performance.

Hi Bigawse

I recently insulated my shed (against the mountain cold) with 70mm thick polystyrofoam sheets. This was for the walls, and it came in at about $50 per 2500x1200 sheet. When I come to do the ceiling (under a tin lid) I will use the same material but with the silver foil already glued to it. I got (and will get) this from Foamex in Revesby (Sydney, but they have branches in other states).

How does it perform? Very well indeed against the cold (I could feel the shed getting warmer and warmer as I worked my way around. Should be the same for heat insulation. I'm not sure if there are any regulations about using this material (in case of noxious gases in a fire - but then I'd POQ anyway).

What I like about this stuff is that it's easy to cut to size (score both sides and snap) and is super easy to mount as it's stiff but weighs nothing (it's 98% air). When it comes to mounting the foil coated sheets in the ceiling they'll be foil side to sun and will simply sit on a few nails banged into the rafters, and I'll then put the timber lining back in place. For you this would mean that you don't have to take the lid off to insulate.

Foamex say that the foiled sheets needs 20mm gap from the adjacent surface, and I reckon that the orb in the tin roof is about exactly that (even though a part of the orb will touch the foil).

It cost me about $270 for 5 sheets which did the walls of my 5x3 metre barn. Some of the cavities were filled with the cut up inserts from my Kapex saw packaging et al, which I was really happy about because it's so difficult to dispose of.

Regards, Brett

I installed a second hand evaporative air con in my 6x10m shed which has concete walls and an uninsulated tin roof. Makes a lot of difference even on low.

I had aircell installed when the shed was built - makes one hell of a difference! The shed is marginally cooler than one half of our house which does not have insulation in the roof

Thanks for your ideas guys

Yeah..will probably go the anticon foil insulation. Think I already have a roll of it somewhere... Maybe a false ceiling will be a go, have to see whats involved..... my mate does it for a living, have to swing him a few beers to give us a hand.....

perth summers make it unbearable in the shed...I should leave a gap between the insualtion and the metal walls hey? Was going to attatch it to the frame...might have to put some more support beams in.....

Next purchase after that will be a whirly bird or extraction fan...

I have aircell insulation in the walls and roof of my 3x5m shed. Very impressed with it so far, and the aircell is very easy to work with - no fibres! If you get it though, make sure you get the thicker version - mine's 13mm thick, and is apparently much more effective than the thinner versions. On a hot day the colourbond on the outside is hot, and the aircell inside the shed is just barely warm.

Banjoping, why do you say the aircell is gimmicky? I'm happy with mine, but am unable to directly compare it with the Anticon that you suggested.

Originally Posted by Beetle Shirt

I aircell insulation in the walls and roof of my 3x5m shed. Very impressed with it so far, and the aircell is very easy to work with - no fibres! If you get it though, make sure you get the thicker version - mine's 13mm thick, and is apparently much more effective than the thinner versions. On a hot day the colourbond on the outside is hot, and the aircell inside the shed is just barely warm.

Banjoping, why do you say the aircell is gimmicky? I'm happy with mine, but am unable to directly compare it with the Anticon that you suggested.

It's gimmicky as it just does not perform for what it costs- it only marginally outperforms just sisalation foil, and at about 6 or 7 times the price.

CSIRO and ICANZ (Insulation Council of Australia and New Zealand) have done extensive studies comparing sisalation (foil), sisalation and bubble wrap (AirCell type products), and sisalation and building blanket (Anticon type products) in various types of roofs over winter and summer.

The most comparable situation is RO900 (flat metal roof) as the majority of the comparisons they have are residential housing or commercial applications with internal ceilings.
ICANZ :: Flat Metal Roof with No Ceiling (warehouse)

In winter and summer the R value of Anticon is from 2.9 to 3.2.

The best they can get the R value of AirCell, even when drooping between the rafters 40mm is 0.79 to 1.6. This is comparable to normal sisalation without the fancy, expensive bubble of air attached to it, with an R of 0.64 to 1.4.

So the anticon is anywhere from 2 to 3.5 times as effective as your AirCell or bubble wrap type products.

Sure, you will notice a difference with the AirCell, but for the same type of money I would have Anticon being 2 to 3 times as efficient every day in my roof.

AirCell have tied up a number of the larger franchise shed companies with agencies for their product, so they tend to push it as the best insulation, when it is not. It has it's applications, but 90% of the time Anticon (or competitors alternative) is your best bang for your buck by a mile.

Can the Bradfords Anticon 75mm be glued to the underside of the roofing in a shed?

Interesting. The aircell has a table on the wrapper giving R values between 1.5 and 3.3, depending on how it's installed, with various compliance standards. More here: http://www.insulvac.com.au/Reflecta-Guard%20Specs.pdf

That link also specifies tight safety mesh, which means no air gap between the metal sheet and the insulation.

It may be a victim of the insulation debacle though - their site protherm.com.au is defunct, with just a few nonsense words on the page. In any case I won't be removing mine in favour of another type, but the next shed may well use something different! Thanks for the info, anyway.

Originally Posted by Waldo

Can the Bradfords Anticon 75mm be glued to the underside of the roofing in a shed?

No, not successfully. Anticon should be shiny side into the shed to minimise fibres into the shed. You will not be able to glue the flimsy fibre insulation to the underside of the roof sheet.

Okay thanks. So then a support mesh fixed to the purlins as you wrote a few posts back is the way to do it.

Originally Posted by Beetle Shirt

Interesting. The aircell has a table on the wrapper giving R values between 1.5 and 3.3, depending on how it's installed, with various compliance standards. More here: http://www.insulvac.com.au/Reflecta-Guard%20Specs.pdf

That link also specifies tight safety mesh, which means no air gap between the metal sheet and the insulation.

It may be a victim of the insulation debacle though - their site protherm.com.au is defunct, with just a few nonsense words on the page. In any case I won't be removing mine in favour of another type, but the next shed may well use something different! Thanks for the info, anyway.

Yeah, I've seen lots of claims over the years from various differing suppliers of insulation!!! The CSIRO and ICANZ stuff is comprehensive, and as independent as you can get these days, so I know who I will be beleiving. For the money asked, the airbubble products do not add anything more than can be gained from simple foil sisalation.

There is no doubt that some of the various alternate insulation solutions have their place, but you really need to look at r value/per $ to determine what is best for your dollar.

Convenience is all well and good, but I would suggest a lot of people on this site almost live in their shed, so I would be looking for effectiveness as well.

Originally Posted by Waldo

Okay thanks. So then a support mesh fixed to the purlins as you wrote a few posts back is the way to do it.

Waldo, you will still need to take the roof off and lay the inso over the roof purlins (or joists). The effectiveness of insulation comes from containing the pocket of air and transferring the thermal energy change from outside into this pocket rather than the rest of the shed. Hence it needs to be as airtight as possible. Taping your inso with insulation tape is also a good idea to maximise the effectiveness.