Collector and Array Mounting and Structural Attachment
This domain tests collector mounting and structural attachment: how arrays are fixed to roofs or ground, how penetrations are flashed, and how wind, snow, and seismic loads are handled.
Attachment and waterproofing
Mount collectors to structural members-rafters, trusses, or blocking-not to sheathing alone. Use manufacturer-approved standoffs, rails, clamps, and fasteners; lag screws must engage the required depth. Every roof penetration needs flashing that sheds water over the uphill edge and sides; sealant is a supplement, not the waterproofing method. Keep standoffs high enough for water flow and debris clearance.
Loads, tilt, and spacing
Check wind uplift, snow load, and seismic requirements for the site. Rows must be spaced to avoid inter-row shading at the winter solstice, and collector tilt should match the design intent. On flat roofs, use ballasted or engineered racks; on shingle roofs, avoid compressing or cracking shingles. Provide thermal expansion allowance in rails and pipe.
Worked example
On an asphalt-shingle roof, a standoff is centered over a rafter, the shingle is cut cleanly, flashing is slid under the uphill shingle, and the fastener is sealed with manufacturer-approved sealant. The rail is then clamped to the standoff. Driving a lag through exposed shingle without flashing is a defect even if sealant is applied.
Traps
Fastening only to sheathing; relying on sealant; blocking roof vents; mixing rack parts from different manufacturers; forgetting expansion and row spacing.