New shed condensation

[pinheadplanet]

I've just built a timber shed from scratch, to replace an old one that was rotting at the bottom, but now it's all finished I'm getting condensation on anything that has liquid in: paint pots, gas cylinders, weed killer, literally everything. It wasn't like this in the old shed. Can't work it out because there is a lot of ventilation in the shed as around the top where the walls meet the roof there is a gap all the way round.

Roof and floor are OSB. Felt roof with bitumen adhesive. Featheredge walls. Couple of single glazed windows and one double glazed, completely sealed in with glazing sealant. Carpet over 80% of the floor.

Ideas?
Thanks

Just adding to this after reading a few other posts. The shed is on an 'open' sub base so water should be draining down, but tbh the rest of the garden is completely waterlogged with all the rain we've had in the UK. The bearers are 3"x2" with a dpm on top before the shed base frame. I've still got the bearer base blocked of at each end with pieces of wood to stop any animals entering that space but I'm gonna open that up now and buy some galvanised wire mesh to stop animals/allow airflow.

Shed is 2.7m x 2.1m

 

[hllns]

Everything's a bit damp and it's still drying out? Could get the windows and doors open whilst the weather's mild to try and get a bit more air through.

 

[mrrusty]

Weather recently has been strange recently. We've had some prolonged very cold weather and stuff has got very cold. Now we have warm wet weather. If there is good ventilation, that nice warm wet air is getting in and condensing on your still cold stuff. This will always happen when you go from cold to wet warm. There isn't an easy fix except heating, and you won't be doing that in a shed.

You'll get less condensation in these circumstances if the warm wet air can't get in!

 

[pinheadplanet]

The old shed is in the sun whereas the position of this one means the south facing wall is hidden from the sun behind next doors fence and the pent roof if sloping away from the low sun, so I can believe this shed is colder than the previous. May be I take all the paints out and get them in the sun if it shines tomorrow

 

[freddiemercurystwin]

Personally I wouldn't store any paints outside in a shed or even in an adjoined garage.

 

[pinheadplanet]

Why's that then? Next door is a painter, he stores all his paint in the shed.

 

[freddiemercurystwin]

In my experience paint deteriorates quicker when exposed to more extreme temperatures/changes. Each to there own, perhaps if your neighbour is a painter he doesn't have tins of paint lying about for a year or so until he uses them again.

 

[MisterBoy]

Condensation simply means the air is touching something significantly colder. When the air temperature increases rapidly, your tins take much longer to heat up so you get the same effect as a cold glass of coke on a warm day.

It could be because odd weather has caused the air to hear you quickly, but it doesn't sound so much a ventilation issue as temperature management issue

 

[pinheadplanet]

Condensation simply means the air is touching something significantly colder. When the air temperature increases rapidly, your tins take much longer to heat up so you get the same effect as a cold glass of coke on a warm day.

It could be because odd weather has caused the air to hear you quickly, but it doesn't sound so much a ventilation issue as temperature management issue

Yeah, I'm thinking where this shed is in the shade, whereas the last one was in full sun, could possibly explain this happening to such an extent as to be noticeable now and not before

 

[MisterBoy]

Do you have any insulation or heating?
I would actually have thought being in the shade would give a more consistent temperature. As someone said, we have had quite unusual weather recently so you might want to wait a while before getting too concerned.
Find a way to deal with the water though so it doesn't pool around the tins onto wooden shelving, etc.

 

[pinheadplanet]

Do you have any insulation or heating?
I would actually have thought being in the shade would give a more consistent temperature. As someone said, we have had quite unusual weather recently so you might want to wait a while before getting too concerned.
Find a way to deal with the water though so it doesn't pool around the tins onto wooden shelving, etc.

No insulation or heating and there's a good ventilation around the roof. I'm gonna remove the paint over the winter into the old shed as that'll be coming down in the spring so it don't matter if it gets wet

 

[MisterBoy]

Ventilation won't help the issue where you have warm air touching cold surfaces and condensation forming... But it should help with mould which is probably more important

 

[JohnD]

Do the gutters and downpipes lead all rain away from the base?

 

[DIY_Doctor]

Just to mention my experience which may help you.

Had my brick shed roof replaced during lockdown around the same time I got uPVC door and window installed. The inside of the roof turned into a black mouldy mess within a matter of months! I can only imagine the installation of uPVC door/window turned the once drafty shed into one with little to no ventilation. Also, I was surprised how much moisture treated (or wet) timber holds which is probably another source of moisture build up (and therefore aiding the mould). And the concrete slab was likely another source of moisture as almost certain it wasn't insulated when laid decades ago.

Have completely rebuilt the roof myself in November, with treated timber rafters but kept the OSB3 deck dry throughout. Generous overhangs of the flat roof mean plenty of cross ventilation of the roof, even now when I've got round to putting PIR between the rafters. Been inspecting the roof obsessively and apart from some dew/condensation around the time of the cold snap, it dries up quickly and thankfully no mould yet (touch OSB).

 

[pinheadplanet]

Just to mention my experience which may help you.

Had my brick shed roof replaced during lockdown around the same time I got uPVC door and window installed. The inside of the roof turned into a black mouldy mess within a matter of months! I can only imagine the installation of uPVC door/window turned the once drafty shed into one with little to no ventilation. Also, I was surprised how much moisture treated (or wet) timber holds which is probably another source of moisture build up (and therefore aiding the mould). And the concrete slab was likely another source of moisture as almost certain it wasn't insulated when laid decades ago.

Have completely rebuilt the roof myself in November, with treated timber rafters but kept the OSB3 deck dry throughout. Generous overhangs of the flat roof mean plenty of cross ventilation of the roof, even now when I've got round to putting PIR between the rafters. Been inspecting the roof obsessively and apart from some dew/condensation around the time of the cold snap, it dries up quickly and thankfully no mould yet (touch OSB).

Did you do a felt roof on the new one? Since the very cold snap the felt on mine has wrinkled, i guess because Expansion of the osb roof and no elasticity in the felt, so it hasn't shrunk back flat