In article ,
Hax Planx wrote:
My ancient detached shop/garage has an uninsulated roof and now that
temps are parked in the 90's with full sunshine most days, the heat
radiating from the roof turns it into an oven. Things inside (like
projects) get warm to the touch and the ambient temperature soars to
about 105°(40.6°C). I've had to move all glues and solvents and
anything else that might be temperature sensitive into the house. As
you can imagine, it makes things like brushing shellac difficult. Any
ideas for a cheap remedy just for the radiating heat problem? I know I
could insulate the roof, but that isn't the direction I want to go with
this space. Before winter sets in, I want to frame about half of the
inside of the building into a room for the wood shop and insulate that,
but I didn't want to do it now. The building is about a 1000 sq/ft and
the roof is over 12' high at the peak, so that isn't very practical
anyway. I was thinking along the lines of maybe using a reflective
coating for the roof or tacking down tarps to cut down on the heat
absorbing properties of the black shingles. Does this sound practical
at all?

There are a few 'cheap' solutions.

1) a large 'barn fan'. venting to the outside. this will help pull the
'inside' temperature down to 'approximately' what it is outside.

2) "water the roof". Intermittantly -- just enough to dampen it, and let
it evaporate off. As long as the ambient humidity isn't excessive,
your water costs are reasonable, and you don't have excessive amounts
of minerals in the water, this can be suprisingly effective. If tap
water quality is suspect, or expensive, build a cistern to capture
the rainwater from the roof, and 'recycle' it.