Hi Corey,
The box needs to be at least 5 to 6 inches to accommodate the depth of the speaker. These speakers work in an infinite baffle so they adapt to a broad range of enclosure sizes. You could have him build an enclosure featuring a top and two sides using the ceiling joists or studs as the other two sides. It's a good idea to isolate the speaker from the insulation. You can also load the enclosure with fiber fill (Dacron-Polyester fiberfill) that allows you to build a smaller enclosure. You can buy this at any fabric store or in a bedding section of a K-Mart or Home Depot. There are some simple solutions to covering the speaker with a wire mesh but if you have the ability to build enclosures, this is the optimum solution.
TL/MA