20 If you require a permit for your greenhouse, then the foundation may also need to be engineered as well to ensure that it meets the local building codes in terms of thickness and depth. Occasionally some customers require a separate permit to engineer and design the foundation to suit the weight and substance of the greenhouse. If the foundation is simple in design (width, depth and indicates the placement of steel), BC Greenhouse Builders can offer the engineered shop drawings for the foundation as an add-on (see image on previous page). We are able to design the concrete foundation detail and have our engineers design it per the applicable code for the home owner’s region as we are licensed in all states and provinces. Concrete Slab vs. Footing When would you build a slab over a footing? A concrete slab is preferred by those that want a faster, easier foundation that does not go down as deep. Typically Many greenhouse gardeners like to experiment with passive heat sources and will paint the concrete dark colors to absorb the sun’s energy particularly on the north wall. ✻ greenhouse tip