Retro fit an "always on" extractor fan to a single garage?
Discussion
Not quite the same but I have a large shed/workshop that I mistakenly insulated, suffered very bad condensation and mould growth inside in the winter months, bought a de-humidifier but that was a pain to empty out every day. Last year I put two small circular vents in the doors and bought a cheap fan and electronic timer set to 6 hours on / 6 hours off and that has worked very well with no mushy cardboard and everything dry and rust free.
I have a solar powered vent on my boat.
It's a nasty noisy piece of novelty junk, but the principle is perhaps sound?
You want airflow when it's warm outside and hopefully dry?
£30 gets you a 30W solar panel which will drive a few computer fans.
The main thing though, is to avoid damp at source, unsealed floor, rain blowing under the door etc etc.
A humidistat fan is another option?
Maybe a timer would make more efficient use of a fan?
Do the maths? 20W fan costs about £50 a year running 24/365? Check that, it's a bit of a guess.
Personally I use a mix of ventilation and a dehumidifier, not at the same time!
In our local Devon climate, outdoors can be damp and humid at times, so vents don't help much.
This time of year, through vents do the trick.
It's a nasty noisy piece of novelty junk, but the principle is perhaps sound?
You want airflow when it's warm outside and hopefully dry?
£30 gets you a 30W solar panel which will drive a few computer fans.
The main thing though, is to avoid damp at source, unsealed floor, rain blowing under the door etc etc.
A humidistat fan is another option?
Maybe a timer would make more efficient use of a fan?
Do the maths? 20W fan costs about £50 a year running 24/365? Check that, it's a bit of a guess.
Personally I use a mix of ventilation and a dehumidifier, not at the same time!
In our local Devon climate, outdoors can be damp and humid at times, so vents don't help much.
This time of year, through vents do the trick.
Interesting. I just had this discussion two days ago with one of the labourers landscaping my garden. He noted that because my garage was joined to next door's that the air wasn't really flowing through with only having ventilation bricks on one wall. His suggestion was also to fit an extractor fan on a timer so I'll be looking into this shortly as I'm experiencing some mould already despite applying yacht varnish to the MDF shelves my racking came with.
beambeam1 said:
Interesting. I just had this discussion two days ago with one of the labourers landscaping my garden. He noted that because my garage was joined to next door's that the air wasn't really flowing through with only having ventilation bricks on one wall. His suggestion was also to fit an extractor fan on a timer so I'll be looking into this shortly as I'm experiencing some mould already despite applying yacht varnish to the MDF shelves my racking came with.
Yes, that's the problem I had with mould growth underneath all the shelves. It was a real pain to unload everything from the shelves (3 towers of 4 shelves) to clean them, wash them in bleach and reassemble then re-stack everything, the fan on the timer seems to have fixed it and it's on from midnight to 6am and 12 midday to 6pm so 6 hours on and 6 hours off.AW10 said:
Just had a quick look - the typical fan uses 15W. So about 1/3 of a kWh/day. So 8p/day, roughly? Negligible cost compared to the issues created by the excess humidity.
But some of the time, the air outside of an unheated shed is warmer and damper than the air within.My car lives outside within plenty of ventilation.
Some mornings when it hasn't rained there is dew on the car.
Will running a fan 24/7 help?
Why not just drill some smallish holes either side and it will just get natural ventilation.
In work there was a metal container and was sealed and got loads of damp. They just drilled every so often and it’s now fine. My garage is fine and the only ventilation is under the garage door. That’s with a washing machine and dryer in there.
In work there was a metal container and was sealed and got loads of damp. They just drilled every so often and it’s now fine. My garage is fine and the only ventilation is under the garage door. That’s with a washing machine and dryer in there.
WyrleyD said:
Not quite the same but I have a large shed/workshop that I mistakenly insulated, suffered very bad condensation and mould growth inside in the winter months, bought a de-humidifier but that was a pain to empty out every day. Last year I put two small circular vents in the doors and bought a cheap fan and electronic timer set to 6 hours on / 6 hours off and that has worked very well with no mushy cardboard and everything dry and rust free.
Think you need to apply dpc to the base/floor, where else is the moisture coming from..?Pistonsquirter said:
WyrleyD said:
Not quite the same but I have a large shed/workshop that I mistakenly insulated, suffered very bad condensation and mould growth inside in the winter months, bought a de-humidifier but that was a pain to empty out every day. Last year I put two small circular vents in the doors and bought a cheap fan and electronic timer set to 6 hours on / 6 hours off and that has worked very well with no mushy cardboard and everything dry and rust free.
Think you need to apply dpc to the base/floor, where else is the moisture coming from..?I've got one of these sucking air in through a standard extractor vent at the top of one end of my shed
https://www.toolstation.com/airvent-100mm-mixed-fl...
And one of these cut into the floor under my shelves/workbench at the other end to let the air out again.
https://www.toolstation.com/hit-miss-vent/p95380
Was getting mould on the underneath of the shelves. Fitted it one January on a plug-in timer to run 12 hours a day- no more mould.
One poster said about sometimes the humidity is greater outside. As I understand it its not just about humidity but also air movement. It's certainly done the job in my case anyway.
https://www.toolstation.com/airvent-100mm-mixed-fl...
And one of these cut into the floor under my shelves/workbench at the other end to let the air out again.
https://www.toolstation.com/hit-miss-vent/p95380
Was getting mould on the underneath of the shelves. Fitted it one January on a plug-in timer to run 12 hours a day- no more mould.
One poster said about sometimes the humidity is greater outside. As I understand it its not just about humidity but also air movement. It's certainly done the job in my case anyway.
Assuming there are no leaks I think the mould problem stems from sudden changes in temperature/humidity. Imagine a cold spell; the fabric of the garage and everything in it cools down. Then things warm up and warm moist air creeps into the garage where it finds lots of cold surfaces for the moisture to condense onto. Being fairly well sealed it takes quite a while for the garage to warm up and the moisture to evaporate. A fan running most/all of the time speeds up this transition period and the condensation isn’t there near as long. Same principle as a Carcoon.
You can’t change the ambient temperature/humidity outside the garage but you can greatly shorten the time period under which condensation inside the garage occurs.
You can’t change the ambient temperature/humidity outside the garage but you can greatly shorten the time period under which condensation inside the garage occurs.
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