i have a grow shed which is plastic about 8x8,i insulated it with that light weight insulation with the tin foil,i stuck that all around my shed, then got some wood and built a shed inside, i then got silicon about 20 i used a coved every gap holes i could see, my door i used velcrow all around to stop anything getting in ,i then cut out my holes for my fan in and out at the top out and down the bottom in i made them air tight, i then put my two plug and grow lights in which are 300 watts but the lumens of a 1000 a fan which my fan goes off and on evey ten minute keeping it at 26 degrees. o and make sure you do the floor too at least four inches off the ground. well my plant are going great, and were the front of ur room is make sure its insulate so wood insult then wood again. and the roof about a foot gap then just chuck what you wont on top of it well that was what i did and its going good took me about aweek and abit to build after work a couple of hours every day well worth it...