BURGESS SHELTER KING, LLC. Tornado shelters one piece concrete 8inchs thick, poured on site. Not pre fabricated. We build 6x8 and 6x10 that's inside dimensions not counting the steps they are six feet two inches tall easy walk down steps double handrails painted inside and out we install a gas shock on the door for easy open and to close, just about any color you would like. Comes with a five year no leak limited warranty call for a free quote, ask for JERRY BURGESS. The Best On The Market! Meets FEMA P-320 Standards.