Keeping things dry in me little workshop

[DigitalM]

I have a 3m x 4m workshop lined with 50mm insulation internally (there's an airgap outside of that before external classing, I posted about that I think in the past but I can't seem to find it). I'm soon cladding on top of the insulation internally with ply ... just 'saving up'!. I've got a chinese diesel heater that I can set to a timer if need be. What sort of things do I need to consider and do if I'm to keep it dry enough not to destroy my tools and things in the winter months. Are there any proven strategies for this sort of thing. I welcome any links to info or videos that any of you found useful, and any feedback of tried and trusted methods so I don't have to reinvent the wheel.

Thanks. DM

 

[TRITON]

Our big workshop - (4500+ square foot) had zero insulation in walls and roof, so in winter we used an industrial dehumidifier.

So maybe something like a small unit in the months where the air/moisture content is high, have something like that running
Alternatively theres dehumidifying tubs filled with those little silicon bead things(like you get with shoes) might at least do something to keep the air a bit drier.

Clarks have a model, not too expensive at £125, and not too big either.
https://www.machinemart.co.uk/p/cla...V5oBQBh2NqynuEAQYBCABEgKo5_D_BwE&gclsrc=aw.ds

Small tubs-
https://www.amazon.co.uk/Babz-Inter...8c3c29632d8874ce56a1466c933&gad_source=1&th=1

Probably better with the plug in unit, as the tubs might probe expensive in the long term

 

[Sideways]

Single car garage workshop.
Single brick. OSB and edpm flat roof.
Zero insulation.

What works for me:
Tools in boxes as far as possible with big 50 or 100g bags of silica gel. (It's cheap by the kilo and regenerated in 20 minutes on defrost in the microwave.
Cast iron machinery: keep the bare metal waxed and covered to keep damp air off it.
Bare steel like the colum of a drill or arms of a power feeder: heavy lathe slideway oil or spray white lithium grease is good protection
Metalguard ultra and similar spray rust inhibitors really helps on bare metal. Renew every few months..
A dessicant type dehumidifier (ecoair DD3) set to a target of 60% RH. Run it on a timer for 1 hr at dusk every day. Dry the air before temp falls and could cause condensation. I used to run it for 2 hrs and that would take as much as a litre of water a day out of the air. It also makes a little warmth as it draws a few hundred watts while running.
Reduce the draughts around the door. A brush strip on the bottom made a big difference. A proper new roller door (seceuroglide) is absolute luxury.
Lastly: be v careful in autumn and early spring : opening the door to let wet air from a rainy morning in on metal that has been chilling all night is a recipe for massive condensation and flash rust.

 

[alex robinson]

I have a 3m x 4m workshop lined with 50mm insulation internally (there's an airgap outside of that before external classing, I posted about that I think in the past but I can't seem to find it). I'm soon cladding on top of the insulation internally with ply ... just 'saving up'!. I've got a chinese diesel heater that I can set to a timer if need be. What sort of things do I need to consider and do if I'm to keep it dry enough not to destroy my tools and things in the winter months. Are there any proven strategies for this sort of thing. I welcome any links to info or videos that any of you found useful, and any feedback of tried and trusted methods so I don't have to reinvent the wheel.

Thanks. DM

Have you actually had problems with damp since the insulation is in? My shed is a similar size and before I insulated it, everything rusted immediately. Once insulated, I have never had a problem and it gets no heating or dehumidifying at all.

You may be pleasantly surprised!

 

[kinverkid]

I have a 12mx2.7m tandem garage workshop. It's insulated on the outer wall and rafters and attached to an uninsulated 1920 house. We've lived here for 31 years and for some reason, nothing to do with anything I've done as far as I can tell, I don't get condensation. That said, on 1st October I will get a reminder from myself on my phone calendar, as I do every year, to wipe all my tools over with my oily rag, rag in a can or wax. I have lots of hand tools and use them all but some of them only occasionally - once or twice a year maybe. So, I take no chances and wipe them with a protective coating. This will be my third year of using a diesel heater. Just set it up yesterday and fired it up today. Still no condensation problems but it is only re-circulating existing air within the workshop. So if the air is dry it should only be circulating dry air. If you do get condensation after firing your heater up, get the room to a reasonable temperature, open the outside door on a dry day and possibly a window the furthest distance from that door for ten minutes. Moist air will normally exit with the warm air from inside. After closing the door and window there should be enough radiating heat present from things around the workshop to bring it back to your desired temperature quite quickly.

 

[Dabop]

Our big workshop - (4500+ square foot) had zero insulation in walls and roof, so in winter we used an industrial dehumidifier.

So maybe something like a small unit in the months where the air/moisture content is high, have something like that running
Alternatively theres dehumidifying tubs filled with those little silicon bead things(like you get with shoes) might at least do something to keep the air a bit drier.

Clarks have a model, not too expensive at £125, and not too big either.
https://www.machinemart.co.uk/p/cla...V5oBQBh2NqynuEAQYBCABEgKo5_D_BwE&gclsrc=aw.ds

Small tubs-
https://www.amazon.co.uk/Babz-Inter...8c3c29632d8874ce56a1466c933&gad_source=1&th=1

Probably better with the plug in unit, as the tubs might probe expensive in the long term

You can actually reuse those 'tubs' of silica gel beads- once they have absorbed as much as they can (weight them before opening, and after a few weeks they will hit their maximum absorption of about 30% more by weight...)

Just bake them in the oven on a low heat setting until they regain their original weight (or you can even get 'bead bakers' to do it) and put them out again- this can be done almost indefinitely...

Another commonly used substance is calcium chloride (readily available as a drying agent for damp rooms and the like at many hardware store or building suppliers, and cheaper than silica beads-look for bags with CaCL2 listed), which can absorb more than 250% of its own weight of water!!! it also can be 'baked dry' at about 250C in a glass oven pot in an oven (and it is low toxicity, with no fumes, like silica gel, so both can be done safely in your normal oven- although your missus might not be approving lol)- might want to invest in a little 'camping cook oven' like the one I use in my caravan in the shed lol

The little black one next to the microwave, cost me under $25 from Woolworths...

 

[Cabinetman]

Time was when with a well insulated workshop you could leave an oil filled radiator on all the winter on a low thermostat. This really did ensure a more pleasant temp on entering and no rust. But it may be too expensive to do now?
If I was working full time in there I probably would but just for occasional days it may be that you just put all your hand tools away in a cupboard with an electric trickle heater in it.
Ian

 

[Phil Pascoe]

I'd be looking at a small dehumidifier rather than a heater.

 

[imageel]

My workshop was never heated and tools never rusted - this metalwork bench I fabbed' lived unpainted for >10y and never rusted...
When I built the shop back in 2011 I had moved from a very damp pre-fabbed concrete garage where everything rusted quickly, but worse I had abusive neighbours on one side such that I had to be careful wrt noise etc so noise insulation was paramount in my new shop build.
I understood all the issues over the years with all these scam home insulation retrofits where folks subsequently plagued with mould etc so I did do a little research into best practice wrt vapour control etc and ended up with shed walls whose section outside->in of -
cedar shingle cladding, breathable membrane, 25mm OSB, 100mm framing studwork infilled with Celotex, polythene vapour barrier, 19mm batten cavity for power etc, 6mm ply internal sheathing.
The window frames I built myself were sized to accommodate DG units with laminated inner glass to not only lessen the chances of breakage from flying timber but also increase the security, and the lights were all sealed using Aquamac 21 seals all round as were the double doors.
When finished, if you tried to slam the door shut you could not because of air pressure within - it was that air-tight!
I did latterly vent the exhaust of my dust/chip extractor externally so that allowed some air movement.
Throughout most of its life the shop was unheated either because it was unused or because once you'd fired up a couple of machines up within 30 mins the place would be quite warm and on more than one occasion whilst working on projects in the winter months I had comments from my neighbours regarding walking the down the garden in only a T-shirt for a tea/fag/comfort break - even on a cold day within an hour it would get pretty warm in there!
So what's the takeaway? IMHO if you can effectively keep damp from entering and have insulation + vapour control to stop humidity from within from entering into the structure of the walls you will have a rust-free whether heated or not.
My metalwork bench as-sold 2 months ago -

 

[pgrbff]

I'd be looking at a small dehumidifier rather than a heater.

But make sure that it works at low temperatures. I have one that really does very little if it is cold.

 

[Sideways]

But make sure that it works at low temperatures. I have one that really does very little if it is cold.

+1
My dessicant model works best in the workshop, a compressor type is more efficient in the house where it's warmer.

 

[Chris Puttick]

Similar experience to @imageel - no heater in the shed, not even any insulation, but it's wooden and breathing. If you go down an insulated route, you can go fully breathable as we did when we built the garden office a few years back; so wool slab + fibreboard + lime plaster. No condensation, no mould. Despite it also being a gym including sauna... Finding someone who can do the lime plaster properly can be a challenge though, if you live somewhere with less old buildings.

 

[Phil Pascoe]

I found the problem before was intermittent heating - I had no rust until I installed a pot belly stove.

 

[DigitalM]

Thanks all. I've ordered a small humidifier, and have some dessicant beads, and also ordered a humidity meter, which will allow me to keep an eye on it. Very grateful for seeing all your approaches and solutions to this. It's a great overview of the sorts of challenges on this topic, almost none of which I was familiar with!

 

[Sideways]

Rust is a chemical reaction.
Reactions slow down in the cold, so rusting does too.
If you can keep the humidity down, winter cold of itself isn't a thread to your tools, actually the opposite. But warm and humid hitting cold metal is the devil...

 

[Jameshow]

You can actually reuse those 'tubs' of silica gel beads- once they have absorbed as much as they can (weight them before opening, and after a few weeks they will hit their maximum absorption of about 30% more by weight...)

Just bake them in the oven on a low heat setting until they regain their original weight (or you can even get 'bead bakers' to do it) and put them out again- this can be done almost indefinitely...

Another commonly used substance is calcium chloride (readily available as a drying agent for damp rooms and the like at many hardware store or building suppliers, and cheaper than silica beads-look for bags with CaCL2 listed), which can absorb more than 250% of its own weight of water!!! it also can be 'baked dry' at about 250C in a glass oven pot in an oven (and it is low toxicity, with no fumes, like silica gel, so both can be done safely in your normal oven- although your missus might not be approving lol)- might want to invest in a little 'camping cook oven' like the one I use in my caravan in the shed lol
View attachment 188824
The little black one next to the microwave, cost me under $25 from Woolworths...

Get an old cool box and put favourite tools in there with silica gel. You won't get the temp variations nor the humidity.