Insulating Metal Shed Obs

[garymck]

Hi,

I'm looking for a way to insulate my metal shed observatory. I've had a dew problem all winter and would also like to assist with heat reduction in summer.

I'm unsure whether a reflective foil type radiant barrier would work. It seems difficult to seperate marketing hype from actual performance. Straight foil seems to reflect 96% of heat and is a lot cheaper than the foil plus bubble wrap..and that bubble wrap stuff doesn't seem any better spec wise?

Opinions please? I've also put in some large vents and a whirlybird...

Just want to make sure moisture doesn't damage my scopes/electronics.

cheers
Gary

[mswhin63]

Foil will radiate heat when it is hit. It will though radiate in all directions including inside when it heats the whole surface so it will heat inside as well. The bubble will create an insulating "bubble" (pardon the pun) similar to the way double brick homes are built for that very reason.

Bubble is not the only material, other more heat barrier material is used increasing efficiency of the insulating layer.

[glend]

The problem with metal sheds is they are usually all metal, meaning that the side walls are heat sources as well, and insulating just the roof may not make alot of difference. The sisilation type sheeting really doesn't stop heat for long, yes it reflects but it gets hot as well and radiates into the room. That said, Bunnings has recently had rolls of rockwool type insulation on sale for $39 I think it was. If you can attach that to the internal side of the roof it could help ( I think having it suspended by a wire grid might be the only way as no adhesive will hold it against the heat it would be subjected to). You could potentially spray insulation foam on the entire internal structure ( probably would need to get someone in to do that). I'd do the walls as well if your going to spray the foam on. Spray foaming would probably be more expensive than rockwool rolls.

Personally I don't leave scopes mounted in my observatory during the summer, despite it being a raised on stump timber structure and well ventilated. I bring them in the house after each session. I use Suntuff roofing with a big solar powered vent at the roof peak.

Good luck.

[bkm2304]

The insulation I used for my observatory is called "AMETALIN", and the type is "Thermal Break 8.0" which states that it can produce an 8 Deg C difference between inside and outside - which it gets close to.

It has 2 outer layers of highly reflective foil sandwiching a tough foam - like layer about 6mm thick. Highly recommended but not cheap.

It certainly takes the "edge" off of the temperature so that a 34 Deg C day is translated to a 26 Deg C interior - not a cool room but pretty good.


Richard

[garymck]

Thanks for the replies, I did have my doubts about the foil alone. The Ametalin looks Ok - I see Bunnings have 30sqm a rolls at $295 (one roll would do my 2.4m square obs) and it was one of the ones I was thinking about, but have no real experience with. I appreciate the real life knowledge! The other options course is to rebuild the shed in timber with fully insulated walls. Would this likely be that much better do you reckon?

Gary

[astro_nutt]

You could try Polystyrene sheeting and glue them with a water-based liquid nails, then cover them with black fabric.
Cheers!

[E_ri_k]

Hi Gary, I had this problem to, temperatures inside got so hot, it could actually hurt my hand to hold it on the mount for too long. This was my solution, its not pretty but it works surprisingly good, better than I expected.

I had some spare silver insulation left over from a renovation, which I duct taped to the roof. It has gone from unbearably hot, to quite bearable. It still gets quite warm on a 35 degree day, but nothing like it used to. Touching the roof from the inside actually feels quite cool, compared to the walls which are lie a frying pan!

Erik

[ZeroID]

Double skinning the roof and maybe the North facing wall is the way to go. Air gap circulation will remove a lot of heat. The good old Landrover had a double skinned roof and airgap for just that reason. When I rebuilt my Ob roof after it's second demise in the wind I was almost going to use the thin corrugated panels as an extra top skin but our temps over here aren't quite as extreme and it wasn't really necessary.
Planting shrubs along the North wall and possibly the East\West walls would also provide a shade\air gap. Might please the wife as well to have it prettied up a bit.

[garymck]

Thanks Erik,

that looks pretty simple as a solution. I'll try it - may also put some Ametalin inside as well. Hell of a lot cheaper than building a new Obs.

My other problem is that one wall is exposed directly to the north, and another to the west. I'm not sure putting shiny stuff on the north wall next to the entertaining are will be allowed though :-(

cheers
Gary

[rogerg]

I recently installed Sisalation under the roof of my RoR Obs open half to prevent dew condensing inside and ripping on to equipment.

I plan to never insulation the walls, as they are E, S and W facing and conduct heat out of the observatory very effectively to assist in cool-down times.

My thread has more info:
http://www.iceinspace.com.au/forum/showthread.php?t=137980

The Anticon I used was about $115 and will insulate better than the foam insulation, but arguably might not look quite as nice because it's thicker so bulges. I spent about $50 in other parts - longer tech screws and tape.

Roger.

[ZeroID]

Doesn't HAVE or need to be shiny, the airgap between the hot exposed surface and the real wall is the insulator and ventilator. Edges must be open to let air through so it takes most of the heat away. You could put a nice wooden fence in front instead, trellis and vine, hedge type bushes.
Roof is same principle, air gap and open edges so the air can blow through. If anything put insulation on the inside of the extra wall but I wouldn't bother.

My North 'Insulation' is an old tin fence that happens to be the back fence of one of my neighbours .