Condensation issues in workshop

[hunggaur]

hi I have a work shop that is built out of concrete blocks with insulation in the cavity and a flat roof the roof void has been filled with insulation.

The whole workshop has been lined with 9mm laminated melimine boards.

However I have started to suffer a problem with condensation on the walls, ceiling and the machines.

Should I put In additional air vents to get greater airflow or should I seal the room more to limit the amount of air flow.


If I need additional air vents should I put a couple at low level in the door and one at high level in the wall.

Cheers

Jon

 

[big-all]

what sort off heating do you have
how often is it heated and to what temperature

 

[theprinceofdarkness]

With machinery its a problem, a few cold days, machine gets really cold. The weather changes (like today mild and moist) when this air touches your cold machines you will get condensation. So for this effect no ventilation would be the best, trying to keep the cold dry air inside the workshop and the warm wet outside. Normally a VCL ( vapour control layer) should be installed during the build as close to the inside as possible. This would be to stop your condensation ocuring in the insulating layer. But I reckon melamine board is a fairly good VCL anyway.
In a houses, keeping the internal temperature above 10 degs C is meant to keep condensation at bay. So you could try trace heaters on your machines.
Frank

 

[^woody^]

A vcl does nothing in terms of internal condensation, nor the OP's predicament.

The problem is one of too low internal temperature, and no amount of ventilation is going to help if the internal air is not kept high enough to hold moisture.

If the heating can't be kept on at low level, then a positive pressure fan may be the answer.

 

[big-all]

i light the wood burner when the internal temperature drops below 8 degrees when not in use if its very cold i will drive the temperature up to around 26-28 degrees to warm up all the fabric and metal for about 2-3 hours this will tend to hold the temperature above 10 into the second day
if the temperature is around the 10-12 mark for a few days i will fire up the burner to maybe 20-25 every 3-4 days

yes i still get some condensation on the glass on the door but not enough to worry about

 

[JohnD]

I wonder where the water is coming from.

Does it have a concrete slab floor, in contact with the wet earth, with no DPM?

 

[^woody^]

Cycling of heating and extreme temperatures can still cause condensation as the air cools. The air temperatres may well be 10 degrees, but the cold machines may be at the dew point for condensation

 

[big-all]

the fact its a wood burner it draws the air out
yes i agree such a variation are not ideal
funny enough i some times store several 2L bottles off irbru on the floor under the shelve and they attract the condensation as they dont change temperature quickly

 

[JohnD]

I was thinking particularly of "condensation on the walls and ceiling" which is unusual in an insulated building if there is no particular source of water vapour, such as a steamy shower or gas heater.

 

[big-all]

i am wondering if the heating is gas or parafin as that would be the most likly cause
i get no condensation at all on the wood or metal only on the glass door and the bru bottles

 

[theprinceofdarkness]

I have an inherited wood burner in my workshop. I have used it for the first two winters but not for this one. What I noticed is that it would melt plastic 12" away from it and the other side of the insulated shed would be freezing. I tried a high power fan on the flue and it helped a lot. Also it needed topping up every 1/4 hour or so. So I use an electric turbo heater, 30p/hour while I am in there, its part of the cost of my hobby. Oh yes, my one ton milling machine and my much smaller lather don't suffer from condensation beading and mild steel rusts really slowly, not noticed any yet in four years.
Frank

 

[JohnD]

A dehumidifier may also help in two ways. They generate mostly heat, due to the intrinsic inefficiencies of the machine. I saw one on offer at Screwyou for £99 with the facility to attach a drainage pipe instead of having to empty the internal vessel.

I still suspect the OP's floor, though.

 

[big-all]

I have an inherited wood burner in my workshop. I have used it for the first two winters but not for this one. What I noticed is that it would melt plastic 12" away from it and the other side of the insulated shed would be freezing. I tried a high power fan on the flue and it helped a lot. Also it needed topping up every 1/4 hour or so. So I use an electric turbo heater, 30p/hour while I am in there, its part of the cost of my hobby. Oh yes, my one ton milling machine and my much smaller lather don't suffer from condensation beading and mild steel rusts really slowly, not noticed any yet in four years.
Frank

i use old single finned radiators as heat sheilds and a ryobi fan on the floor like this
http://www.amazon.co.uk/Ryobi-One-Fan-18v-Version/dp/B000RY2OY4

the radiators are 4" at the closet point with logs stored on the other side no problem