Garage Can Now Breath........

I run 2 dehumidifiers in the house on different floors. They are relatively cheap units, each is capable of removing 10L of water from the air daily however the catch tanks don't hold that much. I'm emptying them daily at the moment. They are 250W per unit, cost to run is cheap for the damage/mould they prevent. If I were installing in the garage I'd pipe the waste outside and leave it ticking over....
They will dry a full laundry airer over night

 

You just had some plastering done with you running 2? they normally have a small outlet so you can run a 10mm tube into a toilet or bath to save emptying the tank.

 

No plastering. My house is 1958 and the walls weren't cavity insulated so winter the walls sweat pretty bad. Top floor is a loft conversion and its gets hot up there in summer. Its been humid outside so I just keep them going. If I'm emptying them daily I figure they must be doing good

 

Best thing I did was fit blinds. Condensation was always worse on warm sunny mornings after cold nights. The air would warm really quickly in the garage from the sun shinning in the windows and so as the air got warmer than the cold metal bikes condensation formed on them. Massive difference now I have blinds.

 

One cheap fix is if its bare concrete floor put an old carpet down and a tray of cat litter (It absorbs the moisture)

 

Basically you could as well store the bike under a "lean to roof" and will save you running the fans.
Your route to constantly ventilate the garage will definitely reduce condensation, but do not forget in the spring/ winter/autumn the ambient air humidity content of the is quite high. So you are "pulling" this air in the garage.
I would certainly insulate the roof to start with. Shouldn't cost you more than £500?
External grade plywood sheets+2x3mm wood battens+ membrane + existing metal roof
There is a lot of info on google how to insulate metal roofs.
Will also keep it a lot cooler in the summer.
Just my 2 pennies worth of.....

 

I have a dehumidifier in the garage and have them pots of desiccant around the place. They're usually 2 or 3 quid from b&q

Got a few bags of desiccant in my tool chests and in helmet bag and leathers pockets when hanging up.

 

I genuinely do not know so am throwing it out, couldn't you fix battens on the inside of the garage, then insulate between them, then shiplap planks like the outside of a wooden shed, on the inside of the garage? The wood would largely breath and so absorb then dry any excess moisture?

 

Sorry you don't get it dude. It's simple once you understand, but then all things are.
Air carrying moisture that is near saturation will loose that water once it cools. By air.. rain, by a cold surface ... condensation... moving it doesn't matter.
Bringing in air from outside could potentially make it much worse if the items in the garage are colder than the air.

 

The dehumidifier is a great idea, the pots are a waste of time unless you are putting them in something sealed. You get little packets of the same stuff when you buy a camera or crash helmet to keep the item dry during shipping. Huge variations in temperature that could lead to the water vapor in with the packed item coming out and water damaging the goods.

 

If the air is a fixed volume, with little circulation then once it's lost its moisture it won't have any more until your condensation evaporates. If the surface is cold and you have 200 times more new air then you'll get 200 times more water.
Cruise ships use condensation water to do the laundry, just a cold surface and sea air forced on to it. Infinite supply of cold water.

 

Insulating the roof will stop it dripping, but I suspect the motorcycle is cold so you'll get condesation directly on it,
Insulate the floor, walls and roof and keep it warmer than the air outside and you'll avoid any condensation.

 

I'm fortunate to have the boiler in our garage that joins the house. I avoided condensation by removing the lagging on the pipes; heated garage. I don't get any dampness.

Agree with others here: By moving air through the garage it may make the problem worse depending upon conditions. I'd go the humidifier route. Or live with it.

 

Your Avatar is a bit dark.....

 

@AirCon is spot on. 100%. I could get my psychrometric charts out and show you but I shant. Its all about RH (relative humidity) etc. The dehumidifier is a good call but its just using more energy. 73m3/h is only circa 2ACH (air changes per hour) for a normal sized garage (3m x 6m x 3m). Thats about right for normal stores etc, bathrooms are at 6ACH. But as aircon says you may be introducing saturated air from outside and compounding the issue. Your best bet is to take a passive approach and properly line and insulate the roof. Throwing vent energy at it is a waste of time on its own. You need to bring the RH down too. If lined and insulated you'd only need an airbrick to naturally vent the space or trickle vent it at a much lower rate. The RH would be less of an issue without a surface to condense on. Plus I advise setting heating to keep it above 15°C even when unoccupied. That way the air is always above dew point even when saturated. So insulate and heat. You could do only the latter but the thermal energy would increase as it would be lost through the roof. Insulate and heat and trickle vent. Job done.

I have an unheated garage but my roof is felt and timber, the walls are brick and insulated outside by the earth and thus hasnt got a cold surface for condensation. I have my bikes covered in winter but its pretty dry in there.

 

Worth a look


https://www.screwfix.com/c/heating-plumbing/dehumidifiers/cat840500