• What determines the height of the product?

For practical reasons, it is advised to extend the height of the inspection box with the lid about 1/2" above the surface surrounding it. That way the lid can be easily removed and replaced, yet the rainwater can drain into the outlet, but the silt from flowing water does not block it.
With the aid of the 2" and 4" extension elements it is easier to follow the level of the substrate and thus adjust the height of the product accordingly

• Why is a gravel strip necessary around an inspection box?

Best practices recommend the construction of a one (1) foot wide gravel strip around the inspection boxes, because it keeps vegetation away from the inspection boxes, and enhances the drainage of surface water.

• Why is the use of inspection boxes recommended for green roofs?

The areas near water outlets are ideal for plant growth because these locations retain moisture longest on a dry green roof. If the outlets remain uncovered, plants will grow into them and they can easily be clogged up. Inspection boxes prevent plant intrusion as well as protect the outlets from debris, UV light. Additionally, these products increase the ease of both inspection and maintenance without requiring complicated dismantling of the system.