These instructions are a guide to build a 8x8 fort that is roughly ten feet tall. 4 foot open area is centered around a square walkway to enter the sandbox on the ground level. Ladders lead into the housing area and sandbox. The housing area is four feet from the ground and the roof starts four feet from the deck Cost: The price for the materials to build this project would be dependent upon what material that you purchase. Some lumber is more expensive than others. However the original structure was created with standard pine so the general cost would be around $400 which would include hardware. Time: I am not going to waste your time to estimate how long it will take you to assemble this fort. Every person has a different speed and it depends on your tools and expertise obviously. As well as how much free time that is available to you. Theoretically it could be completed in one day. Also theoretically it could take you a week. If you hire some of the contractors that I ve heard complained about it could take them a whole year.