we are considering building a upvc ,dwarf wall, p shaped conservatory. we really wish to be able to use this year round , so its stays warm in winter and cool'ish in summer. this conservatory would be bought from a diy conservatory supplier . i want to know the minimum specs for roofs , doors and windows (thickness etc) and also any underfloor insulation or heating to achive our aims. also anyone any thoghts on steel bases against conventional bases.