Help translate terminology relating to flat roof construction
2 LAYERS ASPHALT TO CP144
with SOLAR REFLECTIVE PAINT
on [10?]mm PEARLDECK ([.025/.023])
ON @@@@@ SC3 Joists
AT #00 CENTRES

@@ RRING [PIECES?] [10?/TO?] @@@ 1-30

CP144 is a standards document describing roofing requirements. (It's been superseded.)

Based on some cursory research, it doesn't looks like Pearldeck comes in 10mm thicknesses, so I'm not sure what that number might be. 

SC3 is a European strength rating for joists that has been replaced by a different rating system. (According to the link, SC3 is roughly equivalent to C16)

I'd bet that the last line is "100 CENTRES" with 100 being cm, which seems to be a common spacing for joists.

Pearldeck is hard to find, but based on these two sources:

http://www.woodgreentimber.com/Roofing-Materials-Wood-Green-Potters-Bar.php
http://www.euroken.net/supplies/products.html

It looks like it's an insulation board for roofing.

As to whether or not it's a good roof, cold, hot, or anything else, I have absolutely no idea, and it will largely depend on your local climate. Maybe an expert can add something to this answer, or maybe my translation will let you ask someone you know.

Lastly, not only am I not a professional, but I'm also American (I'm not familiar with common European building measurements/practices), so any or all of this might be completely wrong. This is all based on deduction and Google ;-) So feel free to edit whatever is obviously wrong.

I hope that helps!