Advice on Shed ventilation?

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pdid

Advice on Shed ventilation?

Post by pdid »

Having installed a new shed and insulated and boarded the interior, i`m now suffering with mould likely due to a lack of air flow and damp plants. I have cut away part of the boarding on either side where the roof joins the walls and moved the insulation so as to improve air flow.

Is it worth putting high/ low vents in the gables?

I have also set a fan on a timer to come on for 2 hours daily. Is there anything else I should look at doing, bearing in mind the reason for insulating and draught proofing was to keep it above freezing?

Cheers
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Arlon Tishmarsh
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Re: Advice on Shed ventilation?

Post by Arlon Tishmarsh »

The louvre windows on my g/h are open 24/7 all winter and only closed if it does go below zero. As well as that, i leave the door open during the day. So far there's no hint of mould etc on any of the nana's, aroids or any soft tissue plants that you'd expect to see.

Whats needed to achieve good ventillation is a cross flow thru the structure, same as in a roof space / attic where the air flows from one side to the other and out
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Dave Brown
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Re: Advice on Shed ventilation?

Post by Dave Brown »

mmmm difficult one. An insulated shed is dynamically different to a greenhouse, as if sunny you can leave a greenhouse open and rely on the air being warmed as it passes through, to reduce the humidity. In a shed if no warming occurs, letting in 95% humidity air, will mean you have 95% humidity in the shed :( The air will have to be heated in some way to reduce humidity. Also depending on what you are trying to overwinter you will need light. Most fungus can grow in the dark, as are like herbivores, but plants can't.

This winter is just so wet.... everything is saturated, so the humidity is much higher than last year.
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Kristen

Re: Advice on Shed ventilation?

Post by Kristen »

pdid wrote:I have also set a fan on a timer to come on for 2 hours daily.
I wonder if short ON periods 24/7 would be better?

My conservatory is miles better this year than last, even though much wetter this year and more challenging plants, as new for this year I have a fan.

I have a timer with 15 minute resolution and it is set to 15 ON : 45 OFF during the day and 15:15 during the night (electricity cheaper for me at night). But I have no comparison between 2 hours a day and on/off timer, so it might just "having" a fan that has made the difference.
pdid

Re: Advice on Shed ventilation?

Post by pdid »

Thanks, I have a heater but it is set to come on at 3 or less degrees, I`ll run it for a bit on the days i`m not at work.

Good point re the fan, I think it will be better to run it for 10 mins an hour rather than a solid 2 hour block, I don`t know why I didn`t think of that, I must have been having a blonde moment :oops:

Plant wise I just have brugs, nana`s and cannas, which are dormant, in there permanently. And potted palms, yucca and dasylirion go in if heavy frost is forecast. I have a few windows but they are small, non opening and have secondary polycarbonate glazing.
GoggleboxUK

Re: Advice on Shed ventilation?

Post by GoggleboxUK »

Phil, have you considered a small solar panel hooked up to a 12V car battery which is in turn connected to a couple of computer fans? No power needed as the fans will only run when the solar panel has produced enough charge for the battery.

When researching the airflow system for my greenhouse there are a lot of people using this method to move warm air down through a pipe into the heatsink below but I opted for 4" plastic pipe and inline extractor fans seeing as I had an electricity supply in there.

As for the mould, just grab yourself some of THESE and spread them about an inch deep into a 4" deep garden tray and just place in a corner somewhere.

Each day just pour off the water and stick the crystals in the oven after you've finished cooking your tea. They dry out in about 15 mins and you can replace the dry crystals daily. Alternatively, buy 2 lots and swap the ones in your shed with ones you can keep in a metal tin on a windowsill above a radiator.

They are very effective at reducing condensation/damp.

;)
GoggleboxUK

Re: Advice on Shed ventilation?

Post by GoggleboxUK »

Here's something that might interest you too Phil, an alternative to using louvres:

http://www.hemptechnology.co.uk/hemcrete.htm

It's breathable but also an excellent insulator and totally resistant to mould and mildew.

A couple of blocks cut into the walls at either end of your shed would enable airflow without the loss of heat.
pdid

Re: Advice on Shed ventilation?

Post by pdid »

Cheers Rick, I have power in there so can run a fan ok. I`ll take a look at the crystals, nothing to loose at a fiver a pop. I looked at the hemp but i`m not sure how secure it would be as my bikes will be going in there shortly. icon_thumleft
GoggleboxUK

Re: Advice on Shed ventilation?

Post by GoggleboxUK »

I'd imagine it's fairly secure mate, they build houses out of it :lol:

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simon
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Re: Advice on Shed ventilation?

Post by simon »

pdid wrote:Thanks, I have a heater but it is set to come on at 3 or less degrees, I`ll run it for a bit on the days i`m not at work.
Don't waste money running the heating for short periods of time. It will have no affect. Heating the air doesn't remove any moisture from it. It only raises the temperature further above the due point making the relative humidity lower. As soon as you turn the heater off and the air cools, the relative humidity will return to what it was before.
Addictedtopalms26

Re: Advice on Shed ventilation?

Post by Addictedtopalms26 »

What about a dehumidifier?

Their not cheap though:

http://www.argos.co.uk/webapp/wcs/store ... authToken=
jungle jas

Re: Advice on Shed ventilation?

Post by jungle jas »

Hit and miss vents will help then you could shut them when the temperature threatens to drop. When shut put on the dehumidifier as advised by Scott. icon_thumright
pdid

Re: Advice on Shed ventilation?

Post by pdid »

Thanks for the replies, I can't afford to buy or run a dehumidifier in there at the minute.

Whilst bleaching the mould the other day I found a wet spot in one corner which is probably being caused by earth touching the bearers which will be remedied. I've also installed mini guttering which should also help.

Hopefully these extra precautions plus the cut back boards and fan will go someway to prevent the mould returning. If it comes back i'll fit a hit and miss vent.

Thanks again icon_thumleft
Dave in Warrington

Re: Advice on Shed ventilation?

Post by Dave in Warrington »

Hi Pdid, you're not on your own, I too have mould in my shed.
This is the first time in 20 years !

I'll be trying one or two of the ideas posted but I'm sure the drier weather is helping and I'm hoping for more dry albeit cold weather :roll:
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