Folks,

I plan on building reasonably large wooden shed (either with a concrete or
more likely a raised wooden floor) this summer, it's going to be a non
standard shape somewhat trapezoidal approx 26' by 16' at its widest
narrowing to around 12' at one end.

I'm more than happy with the basic design and I'm happy I have the skills
for the basic construction and so forth however I will wish to insulate the
shed so that the inside remains dry and at more or less constant (extremes
of winter excluded) temperature. If anyone's that interested I'll be
putting a model railway inside it.

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.

--

All the best,

Chris

I would have thought that you would not have a problem without a
source of humiIdity like steam from cooking, drying clothes, people
living in it or rising damp. If you do, maybe because of warm days and
cold nights (as boats do) then a dehumidifier should keep it at bay.

On 20/01/2011 14:40, 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, it's going to be a non
standard shape somewhat trapezoidal approx 26' by 16' at its widest
narrowing to around 12' at one end.

I'm more than happy with the basic design and I'm happy I have the skills
for the basic construction and so forth however I will wish to insulate the
shed so that the inside remains dry and at more or less constant (extremes
of winter excluded) temperature. If anyone's that interested I'll be
putting a model railway inside it.

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.


Insulate and use electric heating, which has a drying effect. My latest
shed has 100mm insulation in the roof, 50mm under the floor and 25mm on
the walls, which seems quite adequate in all weathers.

Colin Bignell

On Jan 20, 2:40*pm, 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, it's going to be a non
standard shape somewhat trapezoidal approx 26' by 16' at its widest
narrowing to around 12' at one end.

I'm more than happy with the basic design and I'm happy I have the skills
for the basic construction and so forth however I will wish to insulate the
shed so that the inside remains dry and at more or less constant (extremes
of winter excluded) temperature. If anyone's that interested I'll be
putting a model railway inside it.

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.

Basically dehumidifier or heat. Dehumidifier is far cheaper to run.


NT

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

On Jan 20, 3:28*pm, Tabby wrote:
On Jan 20, 2:40*pm, 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, it's going to be a non
standard shape somewhat trapezoidal approx 26' by 16' at its widest
narrowing to around 12' at one end.

I'm more than happy with the basic design and I'm happy I have the skills
for the basic construction and so forth however I will wish to insulate the
shed so that the inside remains dry and at more or less constant (extremes
of winter excluded) temperature. If anyone's that interested I'll be
putting a model railway inside it.

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.

Basically dehumidifier or heat. Dehumidifier is far cheaper to run.

NT

Unfortunately dehumidifiers don't work at low temperatures.
Condensation is a well known problem in sheds. Basically as the
weather warms up, the air holds more water. This condenses on anything
that's colder, especially at night as the air temp drops anyway. Large
lumps of metal are particularly suseptible, smaller ones less so. My
lathe always suffers as it's nearly a ton of cast iron.
Stationary engine enthusiasts are always moaning about condensation.
They spray everything with various oils to protect the metal. That may
not be an option for you. I'm assuming your models are relatively
small.
The only answer is to heat, and possibly duhumidify the shed. The
trouble is that's expensive.

John

On Jan 20, 2:40*pm, 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, it's going to be a non
standard shape somewhat trapezoidal approx 26' by 16' at its widest
narrowing to around 12' at one end.

I'm more than happy with the basic design and I'm happy I have the skills
for the basic construction and so forth however I will wish to insulate the
shed so that the inside remains dry and at more or less constant (extremes
of winter excluded) temperature. If anyone's that interested I'll be
putting a model railway inside it.

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.

--

All the best,

Chris

My shed, 14"x 8", complete with model railway. Outer skin horizontal
timber shiplap boards, underneath is a layer of breather roofing
underlay all the way round and including the roof and floor. Roof &
floor is constructed of t&g boards. The roof is covered with top
quality mineral felt, under the roofing boards in between is 50mm
insulation boards fitted tight up to the underlay. The floor as a
layer of breather underlay covered with 12mm insulation covered with
clip fit boards. The inside walls have 50mm insulation fitted tight up
to the layer of breather underlay covered with 12mm sheet ply board.
In the winter I have and electric heater with a thermostat sitting,
this is set just to keep the chill off and try to keep any
condensation at bay. I’ve had no problems apart from the heat in the
summer, it gets a little to warm and a few spiders.

On Jan 20, 2:40*pm, 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, it's going to be a non
standard shape somewhat trapezoidal approx 26' by 16' at its widest
narrowing to around 12' at one end.

I'm more than happy with the basic design and I'm happy I have the skills
for the basic construction and so forth however I will wish to insulate the
shed so that the inside remains dry and at more or less constant (extremes
of winter excluded) temperature. If anyone's that interested I'll be
putting a model railway inside it.

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.

--

All the best,

Chris

Most moisture is likely to arise from the floor. Concrete is OK but
you need t have a damp proof membrane in it. I would consider putting
your locos & any portable electric bits in a cabinet with it's own
chemical dehumidfier.
With the shed as well as insulation, you need to consider one of two
options ventilation, or alternatively, seal it up tight and a
dehumidifier. Permenent heat would be an expensive option unless you
can tap in off your home central heating.

On Jan 20, 2:40*pm, 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, it's going to be a non
standard shape somewhat trapezoidal approx 26' by 16' at its widest
narrowing to around 12' at one end.

I'm more than happy with the basic design and I'm happy I have the skills
for the basic construction and so forth however I will wish to insulate the
shed so that the inside remains dry and at more or less constant (extremes
of winter excluded) temperature. If anyone's that interested I'll be
putting a model railway inside it.

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.

--

All the best,

Chris

The biggest problem is likely to be the roof. The cheapest and easiest
is metal, but you must insulate it to prevent condensation. The
condensation occurs when cold weather is followed by warm when any
metal objects as well as the roof cool the air and cause condensation.

Chris Wilson wrote in
:

Folks,


Thank you all very much for the tips, ideas and "heads up". If I haven't
replied personally it doesn't mean that I haven't read your post, let alone
valued the advice contained within for I have.

--

All the best,

Chris