building is all well and good but not what u are thinking
here is a dry tent (i use this myself u are only limited by the room and how much u want to spend )
1 build a floor ..............what ever size u want u need it off the dirt
2 u can not build a wall and ceiling inclosing it ....or u can buy a tent (i own the tent).......i use a secret jardin dr90 rev 2.5
now u need to control factors to get the best out of your stuff
light.................no light or as little as possible (not sure if green light is safe )
temp ..............78 degrees is the highest ....80 degrees THC will degrade
humitidy...........40 to 60% is the safe zone 50% is the golden area
air current/movement..............air needs to move to remove the water from plant
ok here are some items i found makes this easy
the tent
http://www.amazon.com/Secret-Jardin-Darkroom-Pro-DR90/dp/B004NGKWWI
the rack...........this allow u to get alot of materal in the area and is much better then the hanging them on the line
http://www.amazon.com/Advanced-Nutrients-Quick-Cure-Drying/dp/B004TESI84/
it will fit i own it is really 35'..................i get about 4 oz per teir (if u use all 6 at once u need a low profile fan ) 4 teirs is more then enough for me
now u need a fan ..............i just got this one really like it for the range of motion on the fan makes great air currents
http://www.amazon.com/gp/product/B00873CICA
now u need a carbon filter and fan so u can suck the air out of the tent to keep it from smelling and alerting to ppl (i figure u got own links for that )
the intake u need to make a filter box to clean the air
here is how too................just make sure u get a lvl 10 filter ...wil help control bad smells from getting in somewhat but not 100%
u will need a senor to check the rooms temp and humidity
http://www.amazon.com/Digital-Display-Thermometer-Hygrometer-Humidity/dp/B00IZ8MT2G
finally u need to control mold and the under the house smell otherwise the weed will get little funky
u need a OZONE GEN
http://www.ebay.com/itm/NEW-COMMERCIAL-INDUSTRIAL-OZONE-GENERATOR-PRO-AIR-PURIFIER-MOLD-MILDEW-ODOR-/161042404876?pt=LH_DefaultDomain_0&hash=item257ee0160c
that one is powerful when u turn it on u leave the area it will kill everything in the air as in smell and mold ...........u will have to repeat this every 2 or 3 days
http://www.ebay.com/itm/NEW-LIVING-ALPINE-AIR-PURIFIER-OZONE-GENERATOR-HEPA-ALLERGY-ASTHMA-5-YR-WARR-L-/111408437380?pt=LH_DefaultDomain_0&hash=item19f075d884
this is a weaker model it can be turned on and left running (will not shut off) also has UVC to kill anything it blows tho it ...............i have the 2013 model running in this room it kills the smell of everything( smoke growing smells even gas and mash buckets)........... smells like hospital waiting room
this method ..............if u clip correctly and the humitidy is some where around 40/50 it is 7 days to dry stuff ..............if wetter say 50/60 it is 8 to 10 days before u can safely jar it up and start the final curing