Heating and moisture control recommendations for a shed

[m1ke_a]

Apols for the book but I'm back on to the man cave now that winter's here and have finally finished the interior lining.

Shed is 16 X 12 ship lap and I've added extra wall battens, infilled with 25mm celotex and lined with 18mm mdf.

Running a small fan heater in the recent cold weather has produced noticeable condensate on surfaces and kit within the storage cupboards.

The MDF walls have had one coat of undercoat so far and I'm wondering how many extra coats would be advisable to protect the mdf from damp? Would it also be worth buying a couple of those granular moisture absorbers just to keep on top of things?

The shed will predominately be used to store and work on my bikes as seen here

and in all honesty it's not going to be used day in day out as a workshop. Would one of those greenhouse anti frost heater jobbies be an idea to keep the temp regulated or do folk have other suggestions?

Cheers

Mike

P.S I have more questions on flooring, DGing the windows and so on but will save them for another post.

 

[Dibs-h]

I would be tempted to put in a few of those granular thingys - they are cheap and do work. As for anti-frost type thing - I'd personally use an oil fit electric rad. Very safe.

HIH

Dibs

 

[m1ke_a]

Thanks Dibs, and oil filled rad would make a lot of sense with dust.

It has occurred to me that I didn't paint the inside of the MDF and whilst it's all screwed on, I doubt I could be bothered to remove it and paint. Providing a paint 'barrier' should be sufficient for one side shouldn't it?

 

[Dibs-h]

Mike

By "inside" of the MDF, I'm taking that to mean the face that towards the insulation? If you have fitted foil faced Celotex - then that is providing the vapour barrier, so wouldn't have thought any need to provide "one" again.

It does make me wonder if you have so much condensation - where is this moisture laden air coming from? Or are you introducing it via the cycles - i.e. bringing them straight in from outside?

If it's the latter - then either make the tools cupboards more airtight & perhaps keep some of those granular things in there or perhaps look to fit a dehumidifier in there?

Dibs

 

[Jacob]

....
It does make me wonder if you have so much condensation - where is this moisture laden air coming from? Or are you introducing it via the cycles - i.e. bringing them straight in from outside?.....

Newly introduced heating could be re-distributing moisture - hot air taking it from damp areas and then when turned off depositing it on cold areas. But the overall effect would be drying so you could expect this to ease off.

 

[Dibs-h]

....
It does make me wonder if you have so much condensation - where is this moisture laden air coming from? Or are you introducing it via the cycles - i.e. bringing them straight in from outside?.....

Newly introduced heating could be re-distributing moisture - hot air taking it from damp areas and then when turned off depositing it on cold areas. But the overall effect would be drying so you could expect this to ease off.

Fair point Jacob. Be interesting to see how the OP gets on.

Cheers

Dibs

 

[m1ke_a]

The doors aren't air tight yet and I'm planning on secondary glazing the windows. Consequently the shed doesn't seem to retain heat that well at the mo.

I think Jacob is onto something with redistributing the moisture as I've only just fired up a heater in there. I'll keep an eye on things in the coming months.

Re the painting, the framing is 45mm deep so there's a small void between the 25mm foiled celotex and the back of the mdf sheeting. Whether that'll become a moisture trap is probably something to worry about a couple of years time. I'll do another coat to make the walls a consistent shade and leave it at that.

 

[Fromey]

What's your floor made of? Concrete slab (was it poured on top of a plastic sheet)? Wood on frame (is there any vapour barrier under there, gaps between boards, large knots, etc.)?

I have a concrete slab in my shed. Unfortunately, the whole shed was made by a mad man years ago, so damp rises up through the floor (especially along one edge). I have a humidity meter in the shed and it ranges up to about 72%. Periodically using a dehumidifyer I can get it down to about 60%, but then it slowly rises over time.

 

[m1ke_a]

What's your floor made of? Concrete slab (was it poured on top of a plastic sheet)? Wood on frame (is there any vapour barrier under there, gaps between boards, large knots, etc.)?

I have a concrete slab in my shed. Unfortunately, the whole shed was made by a mad man years ago, so damp rises up through the floor (especially along one edge). I have a humidity meter in the shed and it ranges up to about 72%. Periodically using a dehumidifyer I can get it down to about 60%, but then it slowly rises over time.

A 6" concrete slab was laid to level the site and then the shed put on top. T&G flooring on IIRC, 50mm bearers. There's no DPC or similar anywhere.

I have bits of 18mm ply sheet down in places and have been looking at rubber stable matting or similar for comfort.

 

[Jacob]

...
I have a concrete slab in my shed. Unfortunately, the whole shed was made by a mad man years ago, so damp rises up through the floor (especially along one edge).

You could lay a bituminous floor on top. That'd fix it - very quick and a good working surface. Might still be a problem at the edges but that's down to edge detailing

 

[twothumbs]

By having an air gap between the celotex and the mdf facing is what would be done in buildings (depends on the face of the celotex being sealed). The 'warm' air makes contact with the warm side of the insulation vapour barrier and so does not condense. I am sure it will stablise in time except it is interrmittent use of heating. Best wishes.