View Single Post
  #5   Report Post  
Posted to uk.d-i-y
Terry Fields Terry Fields is offline
external usenet poster
 
Posts: 854
Default Sheds and condensation avoidence thereof


Chris Wilson wrote:

Folks,

I plan on building reasonably large wooden shed (either with a concrete or
more likely a raised wooden floor) this summer.


snip

My main concern is condensation or to be more precise how to avoid
condensation, if anyone could give any pointers I'd be most grateful.


The problem is the faster temperature rises that cause items having a
large (undefined) thermal mass to lag far enough behind the rising
temperature to fall below the dew point.

If your shed gets down to say 2 degC overnight with 50 percent
humidity, then if the morning sunshine causes a rapid rise in
temperature to say 10 degC, it's a racing cert that large items will
only have reached the dew point of 4 degC when the shed thermometer
reads rather higher than this.

As moisture settles out from the air, every surface including internal
ones that have a pathway to air will suffer condensation, with all the
problems that can cause.

Heating such a shed to a temperature having a high probability of
avoiding the dew-point problem (10 degC might be such a figure) would
cost a fortune unless extremely well insulated. Dehumidifiers could be
a way to go, but you'd need one that works down close to 0 deg C and
they are expensive too.

Some combination of insulation, humidity control, and emergency
electric heating would, if you kept your eye on each day's overnight
weather forecast, avoid the most of the problems, but finding where
the balance should be struck between these three is going to be
interesting.

TF