Condensation Hell

[Mezzanine Rob]

The warning from "croppy boy" recently went unnoticed by me due to an attempt to stay away from the computer over Christmas thus avoiding being told off by the family.
Took all my lovely new Christmas gifts down to the workshop today to find everything literally dripping with water. I opened my tool cupboards to find even inside these all the hand tools also covered. I thought I had done enough by oiling all the tools and tables but it doesn't seem to have prevented the entire workshop being turned into a "wet room".
I have set up a dehunidifire running in there at the moment to try to suck up the worst of the wetness.
I know I am going to have to strip everything down and clean, wax and oil.
Is there anything I should do for the electric motors on the machines as condensation seems to be dripping out of the insides as well as down the outsides of the casings?

I never dreamed condensation could be this bad

By the way, I hope all forum users had a wonderful Christmas

 

[kirkpoore1]

I hate when that happens. We're due for a big warmup on Friday, and we have several inches of snow around to provide moisture, so expect that will be my turn soon.

For your motors, use a hand-held blow dryer:

Don't over-do it--try not to spray the water around. And of course don't turn on the machines until they're thoroughly dry.

Kirk

 

[hunggaur]

hi i use to have this problem in my workshop but when i built my new one i got round the problem by putting a double roof on. Which is something that can be fitted to any flat roof retrosepcativley

The top layer is 12 foot steel sheets, these are held off the first roof by 2 by 1 pressure treated. the first roof is a flat sloping roof covered in 18mm ply then roofing felt or water proof membrane. this means that any condensation off the steel roof drips onto the second roof and drains away. inside the workshop between the roof beams i have insulated with 100mm of insulation and them covered the inside of the roof in 6mm mdf, the workshop is warm and due to the void between the 2 roofs and the insulation inside the work shop it is dry and warm and was a very quick fix only costing about £70.00 for the roof sheets off ebay.



may or may not help

just thought i would share

jon

 

[Carlow52]

Nice idea
The fact that the steel sheets keep the snow and from off the lower roof is a major help, as is the airspace in between.

 

[Chataigner]

The recipe for condensation is cold objects with high thermal mass eg tools, then a rise in humidity due to the air warming. How to prevent it?

First question is how does the moisture get in... Cant speak for your shop, but in my case it was a problem of ventilation - too much of it. I have taken extensive steps to restrict air movement in and out of the shop and the problem has largly gone away. If there is no air exchange with the outside, then the total amount of moisture in the space remains about the same and does not normally condense.

If you can control the ventilation, eg open window or whatever, then ventilate when the shop is warm and the air outside is cold, you bring in low humidity air and reduce the total moisture content - no condensation. The thing to avoid at all costs is to ventilate when the shop is cold and it is warm outside. In that case you bring in high humidity air which promptly condenses on the cold objects.

Hope that helps.

 

[matt]

FWIW - My single garage seems to stay condensation free largely because it's got plenty of ventilation. There are gaps around the doors (the main garage up and over and the single door at the opposite end) and when I replaced the roof I never bothered sealing up the gaps left where I replaced some of the rafters.

Another thought... Where does the de-humidifier get rid of the moisture it takes in from the air? I'm not familiar with these things but is there a risk that in a space like a workshop it is simply drawing in more and more moisture from outside the workshop, thus ultimately having the reverse effect?

 

[Lons]

Where does the de-humidifier get rid of the moisture it takes in from the air? I'm not familiar with these things but is there a risk that in a space like a workshop it is simply drawing in more and more moisture from outside the workshop, thus ultimately having the reverse effect?

It extracts from the air and collects the water in to a container in the unit which you then empty. You would be surprised at how much water they can collect over a short period.
Has to be a reasonably sealed room though or you're just collecting from outside. #-o

Bob

 

[Carlow52]

Another thought... Where does the de-humidifier get rid of the moisture it takes in from the air? I'm not familiar with these things but is there a risk that in a space like a workshop it is simply drawing in more and more moisture from outside the workshop, thus ultimately having the reverse effect?

The moisture is condensed into water which is collected.

As long as there is no new air entering the space there wont be any new moisture added.

However it is worth remembering that moisture laden air has a higher vapour pressure than non moisture laden air so over time equilibruim will be reached, hence the need to keep the addition of 'wetter' air to a minimum.

 

[matt]

Is there a risk that the collected water can escape back in to the workshop.

 

[Carlow52]

Is there a risk that the collected water can escape back in to the workshop.

Not unless the container leaks or spills or overflows or is knoocked over
and as water is less of an issue

 

[ondablade]

Some domestic dehumidifiers can be fitted with a hose kit to avoid the need for manual emptying Bob. e.g. EBAC. I bought one, but in practice it's only a length of clear neoprene tube that slips over a barbed connection under a small cover round the back. DIY should be easy.

I put in extra heating in the workshop some months ago, and (not to be glib about it) am happy to report that despite the thaw hitting here a few days ago that I've had no problems at all. The critical factor is to keep the space and hence the machines warm enough that they are above the dew point temperature of the relatively warm and humid air that typically follows the freeze - and so don't cause the moisture to drop out.

If you can remove enough moisture from the air in the shop or keep the temperature high enough so that the temperature of everything in the shop stays above any likely dew point temperature, then even fairly well enclosed kit will lose the moisture fairly quickly - it's surprising how effective diffusion is. The risk is probably to try to run stuff when it's wet.

Heating is probably the best protection in winter, since most dehumidifiers despite the blurb have fairly minimal capacity at low temperatures in winter. Domestic units may stop working altogether depending on how they are programmed. (freeze protection)

Equipment has to be warmed up enough before the thaw sets in though or it becomes a drying out rather than a condensation prevention exercise.

Ventilation is a bit of a double edged sword. It'll possibly help if you have a source of moisture in the shop, but on the other hand will worsen condensation if the effect is to rapidly allow lots of volume of warm and humid outside air into the shop faster than the equipment can warm up.

It's not hard to figure out the psychrometrics, and it makes the mechanics of wood moisture content pretty clear too. Here's a psychrometric chart that shows the relationships between temperature, moisture content and humidity levels: http://www.google.ie/imgres?imgurl=http ... CCgQ9QEwAQ

They look complicated, but are straightforward once you figure the units. To figure if condensation is a risk plot the day's relative humidity (usually 70% plus in milder winter conditions, much much lower in high pressure frosty weather) and temperature on the chart, and follow the horizontal line (constant absolute moisture content in lbs or kg water/lb or kg dry air) from the point back to the curved top 100%RH/dew point/saturation temperature line, and read off the listed temperature.

If your machines are/are likely to get colder than this (i.e. they will start at whatever the air temperature was during the cold snap, and slowly warm up - the lag in their warming is the problem) then you will probably experience condensation.

Lots more psychrometric info on these pages, most of which you don't need:
http://www.cibsejournal.com/cpd/2009-10/
http://www.engineeringtoolbox.com/air-p ... s-t_8.html

 

[matt]

Is there a risk that the collected water can escape back in to the workshop.

Not unless the container leaks or spills or overflows or is knoocked over
and as water is less of an issue

I was thinking more in terms of evaporating.

 

[OPJ]

If you were to consider installing several vents in your workshop, you could install the adjustable type, which would allow you to close them off when you want to heat your space, leaving them open for fresh air circulation when you're not in there. One high and one low is said to be the best arrangement for rectangular workshops. Of course, this could also have some effect on the layout of your workshop, as they'll need to be kept clear for best performance... But still, it's a cheaper solution than buying and running a dehumidifier! ;-)

 

[Chataigner]

If you were to consider installing several vents in your workshop, you could install the adjustable type, which would allow you to close them off when you want to heat your space, leaving them open for fresh air circulation when you're not in there. One high and one low is said to be the best arrangement for rectangular workshops. Of course, this could also have some effect on the layout of your workshop, as they'll need to be kept clear for best performance... But still, it's a cheaper solution than buying and running a dehumidifier! ;-)

Sorry, but I fundamentally disagree with ventilation when you are not there. If the shop and especially the high thermal mass steel and cast iron of the tools get cold, and it then warms up outside and there is air exchange, you will have condensation. Its the same as taking an iced drink outside in the summer, condensation on the outside of the glass.

Either heat the shop (no condensation on warm objects), or keep the air out when the shop is cold and it has warmed up outside which may occur when you are not there to take action. For an unheated shop, you must control the air exchange, only allow it when the inside is warm enough (or the outside air cold enough) to ensure that tools and such are above the dew point.

 

[jimi43]

Well after all this panic I checked my workshop today and the steel bits are cold but there is no condensation (yet).

It was not like this last year before I fitted insulation on the inside of the steel roof....it was literally raining inside back then.

I still went around with some Protec rust stuff....just in case and all my valuable tools are in my son's bedroom (he moved out to a flat).

The infill planes are on my mantelpiece and I think that is where they are staying....I like looking at them!

Thanks for the warnings though....I needed to keep my eye out on the shop more often.

Jim

 

[matt]

If you were to consider installing several vents in your workshop, you could install the adjustable type, which would allow you to close them off when you want to heat your space, leaving them open for fresh air circulation when you're not in there. One high and one low is said to be the best arrangement for rectangular workshops. Of course, this could also have some effect on the layout of your workshop, as they'll need to be kept clear for best performance... But still, it's a cheaper solution than buying and running a dehumidifier! ;-)

Sorry, but I fundamentally disagree with ventilation when you are not there. If the shop and especially the high thermal mass steel and cast iron of the tools get cold, and it then warms up outside and there is air exchange, you will have condensation. Its the same as taking an iced drink outside in the summer, condensation on the outside of the glass.

Either heat the shop (no condensation on warm objects), or keep the air out when the shop is cold and it has warmed up outside which may occur when you are not there to take action. For an unheated shop, you must control the air exchange, only allow it when the inside is warm enough (or the outside air cold enough) to ensure that tools and such are above the dew point.

Ventilation has always worked for me.

 

[ondablade]

Virus
Just to say guys that I've just been told there's a virus on the page with the psychrometric chart. I run a Mac which wasn't bothered.....

Be careful with the ventilation Matt. It takes a quick thaw followed by warmer much more humid air quickly moving into the area for the problem to surface - but if this happens and your equipment is cooler than the dew point of this fresh air it could end up like somebody took a hose to it.

Perhaps you are running enough heating in the shop to keep the kit warm enough to prevent the problem arising....

 

[matt]

Hmmm... the workshop is not heated at all when I'm not in there and sometimes even if I am in there I don't bother. Perhaps I'm just lucky.

 

[motownmartin]

Hmmm... the workshop is not heated at all when I'm not in there and sometimes even if I am in there I don't bother. Perhaps I'm just lucky.

Some people are Matt, I Have been so far, no ventilation and insulated apart from the plastic windows, I only seem to get a problem in late Autumn when the still quite strong Sun heats the shop to around 25 C then at night the cold air hits the warm air and Bob's yer Uncle we end up with Orange Machinery.

 

[stuartpaul]

As someonme who is an owner of the aforesaid orange machinery what do people generally use to protect theirs?

Despite a liberal application of wax I still seem to end up with problems and a discoloured slab of cast iron. Lost count of the amount of time spent with white spirit and webrax cleaning it all off to start again :roll:

Any better ideas?