Best Method to Prevent Condensation ?

[paulkane1]

I recently extended my Workshop,overall it's about 6x61/2 mars.I put on the roof clear transparent sheeting ,more for natural day light,but, I seem to have a lot of condensation in the air,and I can see rust on some of my old tools,I have lying out in the open,Could someone kindly advise me ,what is the best way to cut out the condensation?for heating ,I have a Propane Gas Heater, Is there some extra piece of workshop kit I could get,to cut out the condensation? All help would be greatly appreciated.

Yours Kindly Paul

 

[wizard]

clear transparent sheeting is a big problem the other is the Propane Gas Heater

 

[Racers]

Chuck out the propane heater they put our loads of moisture.

Pete

 

[Hemsby]

Both the roofing material & propane heater are a major cause of moisture #-o. Put the heater out for the scrap man & get a dehumidifier, for heating possibly an oil filled radiator.

The roof will not be quite so easy to resolve without a reasonable amount of work and at least some form of insulation, bang goes your free light. #-o I would imagine at the moment there will be moisture occasionally dripping onto whatever is below

Regards,
Keith

 

[beech1948]

Condensation on galvanised or plastic roofing is endemic and can not really be got rid of. A galvanised roof could be spray painted with foam and this would help but there will always be moisture at the interface between roof and foam.

What can you do:-

1) Throw out the propane heater as it generates condensation from its combustion.
2) Buy some ply and make a tool cabinet for hand tools and in the base put two incandescent lights ( still available for rough use) and a thermostatically controlled switch. Set to about 5 or more degrees. Seal doors with draught proof foam strip.
3) Cover larger machines with cloth covers with something underneath to provide a 3 to 6 inch stand off.
4) Next summer remove roof and replace with rafters, OSB, breathable fabric and the covering of choice eg Steel sheets or galvanised iron
5) Add additional lights to your workshop.

Its a bigger job than you may think. Sorry to be bearer of bad news.

Al

 

[Higon]

Anyone know if this also happen with the twin wall variety of plastic? something like a 35mm variety? Not planning on using it for a roof, but I do have a couple of sheets...

oh and +1 get rid of the propane heater!

 

[KevM]

Another +1 for getting rid of the propane heater - for each 1 kg of propane you burn you're producing 1.6kg (or 1.6 litres - nearly 3 pints) of water!

Apologies to any chemistry professionals out there, but I doubt this has changed since my O levels!

The combustion reaction for propane (assuming perfect combustion in air) is:

propane + oxygen goes to water + carbon dioxide (+ Heat)
CH3 CH2 CH3 (propane) + O2 (oxygen) --> H2O (water) + CO2 (carbon dioxide) + heat

The left and right side need to balance, so
C3H8 + 5O2 --> 3C02 + 4H20 + heat

So, each mole of propane produces a combustion product containing 3 moles of CO2 and 4 moles of water

Propane (CH3CH2CH3 - Molar mass of propane 44.1g), so 1kg/44.1g ~ 22.7 moles

The 22.7 moles of propane will produce 90.7 moles of water.

Water (H20 - Molar mass of water 18g), so 90.7 moles x 18g = 1633g of water.

So, for each kg of propane burned you produce 1.6 kg/litres of water.

 

[graduate_owner]

Could you fit twin wall polycarbonate to the underside of the roof (no point in wasting what you already have), and seal any gaps with foam? That might help the condensation problem and provide some insulation as a bonus. Triple or better polycarbonate sheet would be even more effective, but more expensive of course. And a dehumidifier will remove a load of moisture from the air, but make sure you seal gaps around door and windows. As has been suggested, ditch the LPG because they really do belt out moisture as well as heat. An electric heater will not be cheap to run, obviously, but with improved insulation at least you won't be heating the garden as well.

The other thing about cladding the underside of the existing roof is that you could go ahead and do it now, and not wait for dry weather. Also you can do it bit by bit - no panic if it's not finished and the weather changes.


K

 

[Jacob]

Condensation on galvanised or plastic roofing is endemic and can not really be got rid of....

Actually very easy to get rid of. There needs to be a steep pitch over say 45º and gaps at joints and eaves such that condensation can run down and out.
There's huge scope for passive dehumidification like this (windows etc) but it gets ignored in favour of techy solutions, ideally with dials, control knobs, expense.
The Victorians knew all about it.