View Full Version : shipping container workshop?

16-10-2014, 11:21 PM
I have a plan to cut a 30 ft shipping container down to 15 ft and insulate it to help prevent condensation on my machine tools; mill and lathe.

My workshop is an old farm shed so there is very little weather protection and on a frosty day there is loads of condensation which on a bad day can look like somebody has power washed my machines.

What do you guys think? Will this help putting them inside a container inside the shed?

16-10-2014, 11:39 PM
why not just leave it 30ft ?
more space the better.

or repair the farm shed roof :)

16-10-2014, 11:46 PM
Don't have the space, the 30 ft containers are 500 but the 20 and 10 ft are both 1500. Mainly cause the big ones are hard to handle.

Its not the leaks it's the condensation. The only sure fire way to stop it is to heat the space the machine sits in but this isn't practical so i was hoping insulating the container plus adding a shipping container damp stick will stop the condensation. Not sure it will work?

The other plus point is I could sit a small heafter in the container and I can be warm.

16-10-2014, 11:53 PM
so the plan is to cut the 30ft container down the middle to 15ft.

how do you plan closing up the end.... ?
once its in half what end would you be using..... the part with the doors or with the back end.

i guess whatever end you use, you would have to put the other end on it.
unless you cut 15ft out of the container and weld the two parts back together ?
that would proberly be less work.

16-10-2014, 11:58 PM
No two cuts, one in the middle and one in one of the other sides to end up with both ends still on the container.

17-10-2014, 12:24 AM
yes i see.
what do you plan on using to insulate it.
and what will you cover the insulation with.

17-10-2014, 12:30 AM
Spray insulation and then maybe osb or plywood or possibly just leave the foam exposed.

17-10-2014, 12:36 AM
sounds like a fun project LOL

17-10-2014, 10:20 AM
I've worked out of containers workshops before and they do run with water, I would rather insulate the farm shed.
If you treat it as a 'cold roof' design and use this stuff http://www.celotex.co.uk/applications/flat-roof-insulation/between-and-under-joists
but make sure you comply with ALL the requirements of a 'cold roof'.
My workshop now is a double skin with cavity block building but I still need a dehumidifier going otherwise things get rusty, it's to do with the 'dew point'

17-10-2014, 10:25 AM
Thanks Eddy, did you have insulation in your container?

17-10-2014, 10:45 AM
Thanks Eddy, did you have insulation in your container?

Some were used for sotrage and did not have insulation but vents had been fitted along the top and bottom so that the air inside was at the same temperature as the air outside.
Some were plywood lined and were quite good but I have no idea what was going on behind the wood (between the wood and metal), nobody cared either because they were just scrapped at the end of the job.
There was no heating in any of them and gas heating is the last thing you want due to the huge amount of water they produce.

17-10-2014, 10:54 AM
Thanks thats interesting, sounds like there is a lot more you could have done to help prevent water build up. Im hoping this is possible to have a decent protection. I remeber going to a military event day and they had shipping contianer workshop full of machine tools.

There is some good advise on this website

17-10-2014, 11:04 AM
At the end of the day it's physics, warm air condensing on a cold surface, warm air holds more moisture than cold air.

From Wiki

"The dew point is the temperature at which the water vapor in a sample of air at constant barometric pressure condenses into liquid water at the same rate at which it evaporates. At temperatures below the dew point, water will leave the air. The condensed water is called dew when it forms on a solid surface. The condensed water is called either fog or a cloud, depending on its altitude, when it forms in the air."

"Relative humidity of 100% indicates the dew point is equal to the current temperature and that the air is maximally saturated with water. When the moisture content remains constant and temperature increases, relative humidity decreases"

Control that lot and you're there ! :friendly_wink:

So with my dehumidifier I keep the relative humidity below 50% whatever the temperature and that's mostly to keep my wood right but also keeps rust at bay. If I put my wood burner on the relative humidity can drop to low 40's%

17-10-2014, 12:22 PM
Do you have a fancy dehumidifier?

Would something like this work ok, it appears to have a low power usage so I could have it on all winter doing its thing.


17-10-2014, 12:25 PM
There was a grand designs last week about a guy in Ireland that clagged together 4 containers and the finished article was very nice, foam spray is the only way to go you want no air gaps @ all and all steel must be covered ie main support framework or you will get a thermal bridge, with a dehumidifier as well it should be fine.

17-10-2014, 12:28 PM
There was a grand designs last week about a guy in Ireland that clagged together 4 containers and the finished article was very nice, foam spray is the only way to go you want no air gaps @ all and all steel must be covered ie main support framework or you will get a thermal bridge, with a dehumidifier as well it should be fine.

Yeah that was fantastic, cant believe he spent 14k on a bath!

17-10-2014, 12:50 PM
Do you have a fancy dehumidifier?

This one,


A bit high wattage but the built in humidistat only brings it on when required. It also has continuous drain so no need to keep emptying it.

I can't remember where I saw it but there's web sites where you can determine the size of dehumidifier required for the volume of your space.

17-10-2014, 03:23 PM
If you insulate the entire container really well, it will only require a small heat input (when closed) to keep it warm enough to stop dampness. Remember that insulation will not keep it warm in itself, it just stops heat escaping so you will still need a heat source.

I used to work in a small recording studio where the room was kept closed nearly all the time and had sound-absorption over most of the room surfaces. Even just running the computer and an amp the room was noticeably warmer than anywhere else. I calculated that was probably about 100 watts of heat output keeping the room warm.

17-10-2014, 10:20 PM
Have a look at this thread (http://www.mycncuk.com/showthread.php?p=34400) which shows how to calculate heat loss and insulation needs. I'd hazard a guess that 150mm of insulation with a vapour barrier and 18mm osb would be dry n toasty with a couple of hundred watts of heat input.

18-10-2014, 12:28 PM
I've just insulated and boarded out a 3m x 5m metal shed with wood battens, 25mm Celotex in the spaces and all the insulation joints foil taped prior to boarding out with 18mm OSB.
I'll report back on heating requirements once it gets icy, meanwhile I've fitted an extractor as at the moment it gets too warm for jeans & T-shirt sat at the bench with just me & the strip lights on ;-)

- Nick

18-10-2014, 01:56 PM
Hi, A mate of mine had two 20ft containers welded together and removed the centre metal work creating it twice the size in width, he then foam sheeted it and timbered the intererer leaving the existing wood flooring down. then he proceeded to remove the doors and replace them with an electric roller shutter he now keeps his motor bikes in he has electric for lighting and the shutter it looks really well and without damp it may be worth you looking at buying a 40 ft and cutting it in half then doing something similar

08-07-2015, 11:43 PM
I'm a little late to the party but to prevent condensation you need to move the dew point to the outside of the container.
If you insulate the inside the dew point also moves further in, insulate the outside and the dew point will be on the outside of the steel with minimal heating inside.

In a non breathable structure like a shipping container you also need a a way to dehumidify the air if you are going to work in there. That water you see running down the walls was sweated out of your butt crack an hour ago. :(

09-07-2015, 03:39 AM
Good to know that steel buildings should be insulated on the outside!

Boyan Silyavski
09-07-2015, 08:27 AM
The insulated board, what we call here in Spain -sandwich panel is made from sth like 2x0.8mm galvanized steel or aluminum and 30-50mm expanded polyurethane in the middle. Its price is 20euro/m2 in a normal shop, 14euro/m2 from add or distributor and could be has for as low as 6euro/m2 from dismounted structure. Lengths are up to 15m i believe, width is 1m

Light frame structure with some channel to hold it and there you have something better than a container.

I dont know what is the equivalent in UK but here we also have something similar ready pre[made, they use it for offices in construction sites and is a bit more expensive than container but is insulated, has a door and windows.