Insulating Shed/Garage, again!

[juliussee]

Hi guys,

I know this has been discussed before, but I am having trouble deciding on a definate option. Please help me come up with the best solution.

I am getting a 12.0m x 6.0m metal kit garage built soon. Wall and roof sheeting is colorbond sheeting.

What is the best way to insulate the whole structure? Is it best to get all insulation done while the building is getting erected or after?
Should I use foil backed blanket under the roof sheeting, or that air cell insulation stuff?

What about the walls, should they need to be insulated, before or after?
I don't think I will be lining the walls and ceiling at this stage so how will this work?

Thanks so much for your help.


Regards

Adrian

[Barry_White]

I sold sheds for about 4 years and have been involved in the building trade on and off for the last 25 years.

These concensus was to alway install the roof Insulation as it was being built so that it was directly under the roofing using foil and blanket. Usually use 50mm blanket

Although I have not had much to do with the aircell insulation I don't think it would work as well as blanket and foil although was told it was fairly good and would probably be quicker to install.

As to the walls this could be done in the same manner but if you are lining the walls you could use batts behind the wall lining but foil on the blanket on the inside makes the insulation work more effeciently.

[soundman]

You could indeed do the whole thing in foil blanket if you weren't intending to line it.
The problem with foil blanket is the limited R value it comes in R1.5 i think.
The other problem is the shed installer will curse you. If you have a "talented" and "interested " shed installer you will get a good job.
If the installer is in a hurry and could'nt give a rats, it adds a complication to the whole exercise & thats the last thing you want with this sort of joker.

If you are lining it is easier to do it with polyester bats. The easiest way is to spary glue them to the wall & then clad up later. This will work on the roof too if you are keen.
The above said roofing blanket under the roof is probably the best option & batts in the walls. The poly bats are more expensive but a cheap price to pay for the cumfort of use.
cheers

[juliussee]

Thanks Bazza and Soundman for the advice.



Looks like I will go the foil+blanket under the roof sheets and use batts in the walls after erection later on if I ever get around to it.



You don't need wire mesh under the foil+blanket do you?



Thanks



Adrian

[Barry_White]

We always used wire, and you only need the welded fabric which is 100mm x 115mm squares and 1.25mm wire, unless the shed is very high and then installers may insist on safety mesh which is a little dearer.

By using wire it keeps the insulation tighter against the roofing iron and stops any sag and flapping in windy conditions. It also make installation much easier.

With the insulation it is best to use the blanket with the foil adhered to it rather than separate blanket and foil.

[Leviathan]

Hi all,

I have a similar problem but with an existing 6x7m colourbond shed. Roof steel is 'heritage red', so it gets damn hot.

<snip>... If you are lining it is easier to do it with polyester bats. The easiest way is to spray glue them to the wall & then clad up later. This will work on the roof too if you are keen.
The above said roofing blanket under the roof is probably the best option & batts in the walls. The poly bats are more expensive but a cheap price to pay for the comfort of use.

Whats the difference between poly batts and glass batts? I have some glass batts lying around somewhere ....

Also I've seen posts talk about insulation sheets. Which is the best way to go?


cheers

[Rossluck]

I also have a colourbond 6 X 12. My strong recommendation is: Insulate the roof/ceiling during building with insulated foil of some type, then as you can afford it plasterboard the walls over any type of insulation (batts for instance) jammed into the framework. It sounds difficult but plasterboarding these sheds is easy with self-drilling metal screws, and you don't have to be fancy with the finish. A small window air conditioner, and, as in my case, you can even enter a shed in a Brisbane summer.

[Glenn_M]

Just about to embark on this myself (also for noise dampening reasons) and looking into the different types of insulation available.

Decided to go batts with an internal lining. Looking at the different types (glass vs poly, thermal vs acoustic)......

The documentation for these says that the batts should come into contact with the external cladding material. In my case this is Colorbond and it's already constructed.

Is this really of concern?

Cheers,
Glenn

[Leviathan]

... My strong recommendation is: Insulate the roof/ceiling during building with insulated foil of some type.... <snip>
... plasterboard the walls over any type of insulation (batts for instance) jammed into the framework...

sounds like spray glue any batts to the wall cladding, then plasterboard over is a good way to go

but, given that in my case its existing and has no roof insulation, what would you suggest?

I was toying with the idea of a suspended ceiling with batts on top, then whirlibirds to remove the heat from the roofspace. if I add a small a/c unit might work ok?

or, continue the glue/clad treatment from walls onto the ceiling, creating a cathedral ceiling effect?

which do you think would work better?

cheers

[woodbe]

Just about to embark on this myself (also for noise dampening reasons) and looking into the different types of insulation available.

Decided to go batts with an internal lining. Looking at the different types (glass vs poly, thermal vs acoustic)......

The documentation for these says that the batts should come into contact with the external cladding material. In my case this is Colorbond and it's already constructed.

Is this really of concern?

Cheers,
Glenn

Not sure, but if you are chasing acoustic insulation, you need to bulk up a bit. We had an aircon plant that was rather noisy, so we built a room around it. With standard gyprock on the external face, there was marginal attenuation. We added heavy rockwool and thick acoustic plasterboard to the inside of the room and it made a remarkable difference. We used solid core door and sealed it to the frame with foam windstop, it's airtight.

I've heard that doubling up gyprock (2 or more layers) is also effective.

Hope that helps.

Michael

[soundman]

For a workshop wall some form of timber sheet is better.
then you can put a screw in anywhere and know it will hold.

spray glue will get the stuff up on your roof ( post construction ) thensheet over with white liner board.

forget the whirly bird if you are well insulated it will be a waste of time.
besides i've seen plenty of the cheap domestic ones knackered in the bearings
once they stop spinning they are just a hole in the rood and the rain comes in.

the diference between poly bats and fiberglass is that with fibreglass you will be itchy for a week if you arent carefull.

poly is the same stuff most pilow are stuffed with, dearer but much better to work with.

R2.5 poly bats will nicely fill a 70mm cavity R3.5 and you better use 15mm ply and plenty of screws because the compression mught not seem much but when its multiplied by several square metres thats a lot of force to deal with.

poly does not compress as easily as fibreglass.
cheers

[Barry_White]

For what it is worth I spent several years in sales and design of sheds and most of the sheds sold today if the roof is lined on the inside with say ply or gyprock it will compromise the engineering because whenever anyone wanted to line a shed roof we would have to go to the engineer and he would redesign it.

This would usually mean increasing the member sizes of the frames as well as having closer centres on the purlins.

What you have to remember is the shed industry like most is very competative and they do not over design sheds because every increase in the amount of steel in a shed increases the price and those people who go out and buy the cheapest sheds available will usually suffer the consequenses most.

So as a way of a warning be careful as you wouldn't want it to come down around your ears in a wind storm and then have the insurance reject your claim on the basis of compromising the engineering.

[Barry_White]

Just as an added thought if I was going to insulate the roof of an existing shed I would go to the trouble of removing the roof and installing Anticon blanket and foil which could be done a section at a time.

The time taken to do this would be less than trying to stick insulation up to the roof and then trying to line it around all the framework and in the long run would be more effecient by removing the roof and insulating

[rodm]

After you have glued the insulation to the roof how do you fix the wire to the shed because if we are talking garden sheds you will only have the ridge and wall plate as framing. Also would chicken wire be suitable for this?
I am thinking of putting in a small garden shed with an aircon for somewhere to retreat on those hot days.

[FlyingDuck]

Just as an added thought if I was going to insulate the roof of an existing shed I would go to the trouble of removing the roof and installing Anticon blanket and foil which could be done a section at a time.

Barry, I have been getting quotes for a 20 x 9 shed, and while most are now offering aircell as insulation, one guy still insisted that Anticon was the best. Which one would you go for, and why? I believe that Anticon is about 2/3 the price of Aircell.