Bathroom style extractor in garage?

[Mixersmate]

Morning all -

My garage is detached from the house and is a single skin construction and feels very damp in winter, anything stored in cardboard goes soggy etc.

Has anyone had any experience in fitting a bathroom style extractor fan in the garage? are they good to run 24hrs? Would it work? god knows!

Thanks,

 

[Gavinda]

It's unlikely to make much difference, you'll be extracting air only to have it replaced with air of the same humidity level. Heating the space or using a dehumidifier would be the only way to make a meaningful difference.

 

[Cuffy]

I have 3 of these dotted around the garage, they do take a fair bit of the moisture out of the air. Not as effective as powered unit but something is better than nothing I guess?

Dehumidifier

 

[DXX]

This or similar maybe what you need, it transformed a friends house. That said it doesn’t work on a sealed box, vents are needed.

Positive Input Ventilation (PIV) | Vent-Axia

www.vent-axia.com

 

[david173]

You would have to check with the manufacturer if they can be run 24/7, I doubt they are designed to do this. You could always wire it up with a plug on the end and use a wifi/smart socket to set a schedule for it to come on and off.

We have stored plenty of stuff in sheds and outbuildings in cardboard (used to live on a farm) over the years and never had much issue with damp and none of those were heated so I don't think that just because its unheated you will have damp, however heating as others have said would help but obviously its not very efficient to heat an uninsulated outbuilding, not to mention any fire risk you introduce by using a unattended heater.

What's the roof material? if its tin you could be getting condensation forming on the underside giving you moisture/ drops on to your stuff below?

What's the ventilation like currently? before using anything powered I would look to try and improve the natural ventilation first, we often try to block all holes up in garages to stop mice and this reduces the natural ventilation. I would look to try and have a mix of low and high level vents with vermin grilles to try and get some natural ventilation in there first.

Do you use the garage for anything except storage? such as washing machine or tumble drier or anything like that?

 

[ginkster]

Ventilation is key. As mentioned, you could improve the natural flow of air (ideally in low one end, out high the other). Better still add a fan as you suggest. There are many available that are designed to run 24/7 with a trickle flow and then boost when the light is turned on. That would be good as it will remove the moisture you introduce when in the garage (especially in winter). Gold solution if the others don’t work is PIV as mentioned above with vents to allow airflow out and likely an input vent for the unit (normally designed to go in the loft but can take direct feed from outside if needed).

Heating an uninsulated building makes little sense. It costs you money and will cause condensation issues on the inevitably still cold uninsulated surfaces as warm air holds more moisture. Without ventilation the moisture is still there.

Finally, you may be getting moisture rising from the ground depending on the floor construction. You could lay a DMP sheet down and then put some floor covering (e.g. rubber tiles) over that. That, plus ventilation should solve your issue.

 

[roadtripper]

I store a lot of event gear (PA lights etc) in mine and the strategy I use is this:

Seal most of the obvious leaks. I added a wooden batten holding some leatherette type material flaps across the up and over door that seals the big vent.

Use a dessicant dehumidifier with continuous drain. Luckily I have a sink. The compressor ones really struggle in low temps and the mild heating of a dessicant version helps as a frost guard.

Use a simple clip on fan to keep air circulation up. Damp tends to happen where air sits still and can condense. It also helps spread the dried air from the dehumidifier.

The chemical damp absorbers don't do much in a large space like a garage, at least not for reasonable money. But they are excellent at keep enclosed spaces that extra bit dry. So I have 2 big ones in the trailer as that's full of canvas/wood/iron/wool re-enacting gear.

This approach has kept gear safe in the garage for over 10 years for modest amounts of electricity. The simple clip on fan needs a drop of oil on it's motor axle every year as otherwise it stalls but that one has been running for about 4 years now 24/7. It helps it's super simple just a synchronous AC motor.

 

[dubber36]

Finally, you may be getting moisture rising from the ground depending on the floor construction. You could lay a DMP sheet down and then put some floor covering (e.g. rubber tiles) over that. That, plus ventilation should solve your issue.

I'd be more inclined to build some raised timber plinths to keep your boxes up off the floor. Added crossflow ventilation will draw moisture from the floor without it soaking into your cardboard boxes.

 

[General-Monty]

I had a very damp garage. Everything was damp and went rusty within weeks. It was a very unhappy place to spend any time during winter too.
I tanked the walls of my garage, battened it, and 12mm plyed it. The ceiling got some celotex and was ply lined and the floor got resin painted. Now the moisture can’t enter. When I’m in there in winter restoring motorcycles I’ll have a heater on for a bit and going in and out is enough to circulate a bit of air.
It’s dry as a bone in there. I love it, spend most of the winter in there. Nicest room in my house !

 

[DXX]

An easy way to increase airflow around storage items is to keep a gap between boxes and the walls / floors.
Putting boxes on a plank or similar supported by a few battens is a cheap solution.

 

[roadtripper]

Just to add you need to pick your strategy.

Either reasonably seal it and actively dry the air (which needs a dehumidifier with continuous drain) or keep the air turning over.

If you seal and don't actively dry you'll just create perfect damp conditions. Rain will come through single brick walls in a storm.

If you vent and actively dry then your trying to dry the outside, that's just going to get expensive!

It's worth try the vent first as that's less outlay and running costs. It didn't do enough for me with electronics. However adding a fan to keep the air moving really really helped and that's cheap to try.

 

[ginkster]

I'd be more inclined to build some raised timber plinths to keep your boxes up off the floor. Added crossflow ventilation will draw moisture from the floor without it soaking into your cardboard boxes.

Absolutely. The DMP is more to stop moisture rising into the garage in the first place rather than venting it once it has.