1. Flat roof: General

2. Flat roof - Generalities
Changed requirements due to the PV system
Roof types
Planning process
Flat roof solutions
Conclusion
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3. Changed requirements to the buildings because of PV systems
Noticeably elevated loads on the roof
Own weight of PV system
Wind loads
Vertical (= uplift)
Horizontal (= slipping)*
Changed load on the roof: point loads as apposed to previous consistent surface loading
Additional operational demands on the roof cladding
Slipping of the mounting system, frction with roof surface material
Roof penetration
Tightness
Insulation *only at firm embedding in the roof
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4. Important roof construction features for the PV system
Permissible additional load
Per m² roofi surface
As line load/point load on bearing substructure
Consistence of roof surface
Trapezodial sheeting (exact shape, material, strength)
Gravel fillings (Weight per m²)…
Substructure
Exact position of beams and distance between each other
material and dimensions of beams
Distance to surface of the roof (Insulation material, thickness,…)
Superstructure or special requirements: roof windows, chimneys, ventilation shafts, fire access points etc.
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5. Planning procedure flat roof
Gather information about the roof:
Location, building height etc. (cf. planning aids)
Construction information about the roof: Permissible additional load, roof cladding, substructure etc. (cf. previous page)
Estimation if a standard system is suitable or not
Via customer
Via Mounting Systems
Standard suitable:
Quote standard material
Order
Standard not suitable:
Request to Mounting Systems, enclosing the necessary information
Project quote by Mounting Systems
Order of project material
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6. Flat roof solutions System with ballasting
On concrete strip foundation
On sheets with spread-out ballast (e.g. gravel)
System with roof penetration:
With concrete anchors directly through the footers of the triangle
With various fixings and bottom rail/beam constructions
Additional measures for the reduction of the additional load:
Enlargement of the distance between the rows, reducing overall load on the complete roof
Reduction of the module pitch
Interconnection of the rows, support against the attica, counteracting horizontal loads
Wind deflector on the back of the module rows
Some roof penetration points on the outer margin of the otherwise ballasted PV system
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7. Flat roof - Conclusion
A flat roof PV system changes the roof load significantly, so that the building‘s static has to be considered at each project
Depending on construction type and static of the building, different solutions of mounting system may be suitable
According to the solution option the resulting prices of the mounting system can vary widely
Gather the building data at each request for a flat roof!
Take into account increased planning time and costs according to the building restrictions!
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