Thread: Shed condensation problems

There is no way this problem can be solved "on the cheap" and how cheap will doing nothing be once your TS has a whole pile of rust pits?

Airconditioning or heating an uninsulated shed is a complete waste of money.

Sealing the shed and insulating it will be a start to minimising the problem.

Then you need ventilation that you can swing into action when the RH is lower and the temp is higher usually later in the day.

Hi Pat the Rat,

I live in Mt Evelyn, where it gets pretty damn cold in the mornings.

What I've done (with a lot of help from my father) is lined the shed using the slats off old pallets. Took while to get all the timber together, but works a treat.

Shed is pretty warm, no condensation, and all done for the cost of the nails.

Cheers.

Hi pat, what you need to achieve is a barrier between the cold air in the shed and the warmth of the sun hitting the shed roof. How you do this could be achieved in many different ways. As the others have suggested lining and insulating is one option. If you go with this option when installing insulation make sure bats aren't touching the tin and there is enough space above them for ventilation. otherwise condensation will end up in the bats and then mold will grow.
Another option is to replace existing sisalation/silver paper with a blanket sisalation(can't think of its brand or product name). This is basically two layers of silver paper with a thin layer of insulation. I can't see why this wouldn't help solve the problem and possibly cheaper than lining ceiling.

Hey Bob: thanks for that overview, which makes a lot of fundamental sense. And Grey Beard: that approach covers off the economic hurdle beautifully. Finally, jrock, thanks for your info, which has given me a few ideas based on better background knowledge: I think, however, that that double-side sisalation doesn't come cheaply. Ideally, I'd like to find the cheapest method of installing a ceiling & wall lining, to which I can attach that sisalation (or an alternative) between the lining and ceiling/cladding. I detest going to Bunnings (particularly for advice), but in this instance, economically I mightn't have an option. Barring a plentiful supply of old pallets, has anyone any ideas about the simplest & cheapest lining material??

When I built my new workshop recently, a friend with a similar shed warned me of the condensation issue and the air cell insulation solution.

I built it as he suggested - with cheap garden wire from Bunnings as a support to keep it from sagging, and this is the result.



It's worked a treat - no problems at all with condensation and it's a pleasure to work in on hot or cold days.

I imagine that if you don't install it at the start - it could be a bit of a problem to install afterwards - might even ave to lift the roof sheets and install the wire then insulation - then re fix the roof sheets maybe.

Others mileage may vary.

Most of the Kingspan Aircell products can be retrofit by fastening to your battens with tek screws (the foil has a reinforced scrim) and then taping the joins to seal the moist air in the shed away from the cold tin.

This article here on my blog covers a little about some products that could assist.

Originally Posted by Timless Timber

I imagine that if you don't install it at the start - it could be a bit of a problem to install afterwards - might even ave to lift the roof sheets and install the wire then insulation - then re fix the roof sheets maybe.

The older section of my shed is about 6 x 4 and I installed insulation afterwards about 18 months ago
I toyed with the idea of taking the roof of but in the end I installed the insulation from underneath .
Basically I cut the roll of support wire and insulation to fit between the purlins.
Then I loosely installed the support wire leaving enough of a gap so I could slide the insulation into the gap.
Then I tensioned the support wire to the purlins which pulled the insulation upwards.
The insulation still sags a little but I am very happy with the way it works.
Here's a pic of the refurbished old part of the shed.

I removed the roof sheeting on my shed then laid down sisalation to reduce the heat during the summer months ,however it has also kept condensation to a minimum.
On lining the shed walls I inserted Pink Batts to also add to the comfort zone in all now a comfotable work environment which I have enjoyed for a number of years!
Draught retention also is a must on keeping the environment integrity to your likes/

Cheers

Timless & BobL: I think I now get it! Thanks for those tips: I guess the rigidity of the air cell insulation is critical. John: do you mean by "draught retention" that it is imortant to have a flow of air through the shed to assist with removal of condensation? If so, my concern is that the humidity levels up here are VERY high, and the ingress of highly moist air might defeat the whole cunning plan on which I'm about to embark?!

Shedblog: did you put spacers between the battens and the insulation surface??

Once again, thanks for all your advice guys!

Originally Posted by Pat the Rat

Shedblog: did you put spacers between the battens and the insulation surface??

Generally Spacers are used on walls not roofs.

The idea is to create a small air space between the Insulbreak and Roof tin.

Retrofit to the underside of purlins gives that air gap. If installing by removing roof sheets then you allow it to sag 40 mm.

There are comprehensive instructions for the various Kingspan products on their website.

Cheers

Thanks Shedblog: finally got to your article/site, which is highly informative/comprehensive. You wouldn't happen to have a retail outlet near Lismore, would you? Really like to see/touch product before I commit to purchase!!

Originally Posted by Pat the Rat

John: do you mean by "draught retention" that it is imortant to have a flow of air through the shed to assist with removal of condensation? If so, my concern is that the humidity levels up here are VERY high, and the ingress of highly moist air might defeat the whole cunning plan on which I'm about to embark?!

!

Perhaps I should have been clearer in that any ingress of cold air especially during the winter months and in the lower lattitudes will not make for a happy environment.
Case in point was that I had a sliding door on my shed that was never snug and always was problematic in allowing cool air into the shed over night.I have now sorted that out with a new better fitting door.
I remember my father complaining about a cold shed in the winter months but being a timber built structure he did'nt have condensation issues either like we have with the tinnies.

Cheers

Originally Posted by Pat the Rat

Thanks Shedblog: finally got to your article/site, which is highly informative/comprehensive. You wouldn't happen to have a retail outlet near Lismore, would you? Really like to see/touch product before I commit to purchase!!

Sorry Pat, no physical outlets. Can simply recommend whole heartedly, the Kingspan Products and refer you to their 15 year warranty.

Originally Posted by Shedblog Au

Sorry Pat, no physical outlets. Can simply recommend whole heartedly, the Kingspan Products and refer you to their 15 year warranty.

I would be wary of the insulation benefits of these products. They are essentially radiant heat barriers and convection stoppers, similar to other sarking such as sisalation.

Their insulation value is low; certainly nowhere near the R = 4 level that you need for effective shed insulation. Just try and find the R-values of their products on their website:

R-Values - Shed Roof And Wall - Please contact us for more information.

The R-value is the major marketing specification for insulation and if it was adequate then they would be shouting from the rooftops.


Fair Winds

Graeme