48x66 Note the fiberglass panel strip just under the roof, really helps with natural light. Constructed with Magic Trusses, keeps the interior open. And no matter how big you will fill it up and then some. Our floor was not concrete when we moved in and during the spring thaw so much moisture would come up from the ground it would drip from the ceiling on the inside. I put down 6" with rerod and stopped the problem. Hope this helps.