with the help of my son we managed to insulate the roof of the shed where i store some of my astro stuff and have a fridge etc. the heat in there during summer is unbearable - normally but it is now several degrees cooler inside. made a huge difference. this weekend was a huge test being so hot. as for the product i fully recommend its possibilities for your observatory
When we were living in Perth, summer was a bummer, with up to 3 consecutive weeks over 35 degrees.
The back shed was our office, and was unbearable, as you note.
I had a mate who was working at a polystyrene place, and he arranged for a huge delivery of 2-inch thick polystyrene rejects (there was a tiny line running down them). It cost me a bottle of Jack Daniels to get enough delivered, to cover the inside of the roof, all the walls and the doors. To stick it, I used industrial strength liquid nails.
Then I cut a hole in the wall and fitted a small aircon unit. On 43 degree days, it was a lovely 25 degrees inside.
Finally, I ran phone and network cables underground from the house, and my job was done.
