How do you fight workshop/shed condensation

I was doing that, but the oil tended to emulsify and act like a poultice on the bare metal. strangely i went out to the shed today and the machines were fine , no condensation to be seen, the uni-bond humidity absorbers did have some water in them though.

The shed itself is the usual cavity cement block construction with concrete floor. I wouldn't have built it like that personally, the father built it and its not a good job.

There are two problems with de-humidifiers - quite expensive to run and the typical ones don't work at low temperatures. They work well at 20C and pretty much not at all below 5C. I found it easier to stop heating the workshop and to keep machines covered up and things like chucks etc in zip lock bags. Keeping chucks in bags aslo keeps any avoidable dirt out.

One thing that will cause condensation is the sun streaming in on a cold winter's day. Everything warms up, sun goes down, condensation forms.

I had wondered about the effect of a large window (which it has) on the condensation situation in the shed. Natural light is so much nicer to work in than artifical light though.

I have been using dehumidifiers for years. over 20 years ago I worked for a paper storage company and they held masses od docs from insurance companies, banks etc. the holding site was an old corrugated roof warehouse block. there was no heating and just around 10 small dehumidifiers. They worked. I also have used one to keep my motorhome fittings dry and its been preforming that duty for 9 years with no faults. I can,t see how they are expensive to run, they only work when they need to. as to temp never found that to be an issue. After fitting the insulation the workshop never drops that low.

i built my shed 2 years ago now. brand new bought from the local shed and general garden wooden building emporium which has now disappeared..!!

I insulated with 1 inch thick/thin polystyrene boards. Floor, roof, walls and door. then laid10mm plywood from the local plywood supplier over the top of that. Again, floor, roof, walls and door. my 12X6 shed now measures 5'6" by 11'6" internally.

in addition to this i use a small cheapo electrical blow heater set to give a low, comfortable heat, and left turned on 24/7. It gets turned up slightly in the colder weather that invades my small area of the world [UK] occasionally, but otherwise is left alone.

I have absolutely NO condensation at all. At least i have seen NONE at all in the time the shed has been built and inhabited. it contains tools such as a lathe and a miller and associated tools and lots of wooden cabinets to support and store said tools. Again,NO condensation.

make of this what you will. there are also 3 windows in the shed. Glass. and never a bead of damp on any of them.

in the past 2 years i have had ZERO - 0% of condensation.

cost of the heater is minimal due to the thermostatic control.

Edited By Ziggar on 12/11/2013 22:02:49

I double glaze my windows in my workshop/shed with bubble wrap . I cover my lathe's and mill drill with aircraft wheel cover material my son got me when in the RAF silvered on outside and rubberised on the inside
walls insulated with waterproof Millboard my Father got me Seem to work ok
Nobby

Yes, but it forms on the window not on the previously warmed machines. Collect the water as it runs down the window and you have a de-humidifier

Russell.

this problem has been running on for a number of years in threads not only in this forum but others.
as far as I can make out it depends on, type of shed, position, insulation or not, windows I could go on suggest looking up old threads.

Fizzy changing the subject how is twinkle, I got told at the weekend that I was going to be a Great Grandad when tribe came round
Bob

Fitting a blind to workshop windows can get round the problem of the sun heating the air inside and causing condensation on cold surfaces. Since this is mainly a problem early in the morning after a cold night the blinds can be removed when the workshop is occupied. Over the winter I cover my machines with a double layer of bicycle covers from the pound shop and stick one of these small silica gel moisture absorbers under the cover. Every couple of weeks I plug the silica gel units into the mains to reactivate them. I have done this for a number of years and don't suffer from condensation, although the workshop is insulated but not heated.

Doug

Be careful with the dehumidifers, dry air can cause irritation of the nose and throat and mummification of everything else.
Hi Terry,
As a now retired local councellor there was many people who would have liked to have mummified me.
seriously when you say mummification do you mean that it dries out everything oil the lot.
Bob

My solution is a differential temperature measuring between outside in inside. I keep the inside temperature with an electrical heater 3 degrees higher then outside. This works for me allready 20 years at low cost!

Mart Hurkmans, Netherlands

Hi Ronan

My garage conversion is in a previous write up on 'heating the workshop'. In essence studding frames, Celotherm insulation (same as Kingspan) fitted, overlaid walls with OSB sheeting, Celotherm fitted to access door & roll up door, loft space rafters covered in plasterboard, loft insulation on top (space blanket give 6" thickness),so far this year has kept the temp stable at 10*C even with the warm weather we've had, supplemented for winter with 2 small oil filled rads, one either end of garage which were switched on yesterday for the first time for about an hr, brought the temp up to a cosy 14-16*C, then turned thermostats down as it was getting overwarm, so far no need for dehumidifier & no signs of rust.

George

Dehumidifiers work superbly, providing the workshop is reasonably airtight and not draughty. I have used one for six years in a large workshop (triple garage), with a well insulated ceiling but bare brick walls and solid concrete floor, keeping the RH below 60%. At that humidity there is no rusting whatsoever. As a bonus, you walk into the workshop early morning when it is 5 degC and the fact that it is dry makes it feel much more pleasant. After a few hours with electric heating it is up to 14 deg C and the dehumidifier no longer comes on because the warmed air is drier (relatively). When I leave at the end of the day the dehumidifier works hard on the cooling air to control a potentially increasing RH.

Yes, the condensing surface dehumidifier is much less effective at 5degC but at that temperature the air contains a lower mass of water, and the external air leaking in is typically colder, and thus carries less weight of water, even if its outdoors relative humidity is 100%.

Silica Gel bags simply would not cope except inside sealed plastic bags - there is far too much water to be removed.

My dehumidifier is an EBAC CD35, measures 14"x14"x28", costs around £300 and rated at 350 watts typically runs at a 30-50% duty cycle for me. Working fully I find it removes 80-100 cc of water per hour at 60%RH and 10-14 degC. They need a drain drilled through an external wall, unless you enjoy spending time pouring away a litre or so per day!

Norm

There seems to be some confusion over what causes condensation. Condensation will form on a machine when the temperature of that machine is below the Dew Point temperature. Heating or cooling the air in a room without a dehumidifier will not change the Dew Point. So you can let the sun shine in, or turn on an electric space heater without risk but also without short term benefit. Machines have a high thermal inertia so they stay at a more or less constant temperature.

There are a number of weather forecast sites that give both temperature and humidity forecasts. From those figures it is relatively easy to calculate the minimum temperature of your machine tools to avoid condensation. They can then be heated to a few degrees above that temperature at minimum cost.

As an example, the forecast for tonight in Cambridge is a minimum temperature of 5 C with 90% RH. That equates to a Dew Point of 3 C so if your lathe is warmer than that you will not get condensation on it.

Russell.

Sorry about that! My reference to a previous posting seems to have gone wayward, to say the least!!

I'll try and make a better job next time (novice at this game!!)

Trev T