This modular house will be used for tactical training of the Fayetteville Police Department. We installed it out of doors underneath a wood pavilion. Our turn-around time for building was two full work weeks and installation took only 2 days with 5 workers.
We laid a Geosynthetic Fabric on the rolled out rocks and then installed a flooring called Ultra Base that helps create a level and uniform floor. Our customers can specify whether or not they want an ultra-base and can customize the color. Here is what the Ultra Base looks like before the house is installed on it. 
We used pressure-treated panels for this house because they can withstand warping and moisture damage better than non-treated panels. In climates of very high humidity or harsh weather, such as North Carolina, we recommend using pressure treated panels to protect the wood panels and increase the life of your modular house.
This is the house during installation. The ground is gravel, so the Ultra Base gives uniformity and level (which also makes it easier to install!). The pressure treated wood usually has a green or dark brown color. You can order the pressure-treated wood as-is or order them painted in any color.