Shed ceiling always very wet

BarneyMc

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I have a detached, block built shed with galvanised roof. I keep my oil boiler in the shed. The inside of the roof (galvanised ceiling) is always very wet.

I seems to be condensation rather than a leak because the wetness is spread all over the ceiling and is in blobs rather than dripping in one place.

Is there a way I can get rid of this?
 
Your oil burner would appear to be the culprit. A lot of factors could be contributing to the build up of condensation. Is the burner properly vented? Is the roof low?

I had a galvansied shed and I tacked on felt and held it on place with chicken wire ... something like that will help but not eradicate the condensation fully. This may not work for you as this was done prior to the galvanise being put on.

Also, you need some vents if the garage is too air tight this would be a contributory factor also.
 
Hi Paddy. Well the boiler chimney goes straigh outside but there may be some heat coming from the boiler itself when on. I got the shed plastered some months ago and got the guy to fill up some gaps near the roof... maybe would have been better not! I'll snoop around again and see what I can find. Thanks!
 
I reckon sticking in a few vents would help.

The oil burner is keeping the heat in. The heated vapour is rising and hitting the cold galvanise and condensing it back to water droplets.

You can hire the hole cutter from a tool hire (not all of them would stock them because ppl damage them boring through all sorts of stuff in walls and it doesn't pay the tool hire company to stock them). Bore some vent holes get some covers and voila ... it's a start. Enclosing your bolier would be the next step ... it would also reduce heat loss ... more heat in the house ... more efficiency.

Galvanise is a great fix but a b*&*h for condensation. You'll minimise but probably not get rid of it.

Anyways ........... best of luck with it!
 
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You could use a dehumidifier, I have found it great to get rid of condensation all over my house
 
You could use a dehumidifier, I have found it great to get rid of condensation all over my house


Would it not be an endless circle of oil burner .... dehumidifier? Best option would be to try and put in as many vents as possible, insulate the boiler and take it from there.
 
Barney, if you insulate the roof on the inside this will stop. Unfortunately, as the roof is on you'll have to spray eurathane and this can be expensive. Alternatively, nail on some felt underneath and create a 'funnel' to catch the condensation.
 
OK then. Staple on some clear polythene and funnel it to the lowest corner where it can be collected. Cut a few bits of polythene (2" x 2") an put a couple on them over the polythene where you are going to pierce the membrane.
 
how do you insulate the boiler?


Some kind of a fire-block material.

Myself I'd build a block wall with some kind of steel door and a concrete ceiling (possibly make a slab or two). This would at least have the effect of containing some of the heat generated from the boiler.
 
Your problem is continuation, this is due to the warm air from your boiler meeting the cold roof, so you will have insulate the galvanize, or strip the roof and put in a drain off membrane like felt etc, My answer is to fully insulate the under side of roof, this will stop the hot air from meeting cold surface.
 
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