Ballasted mounting system for flat roofs – EAST–WEST orientation
Manufacturer: SOLTREK CO s.r.o.
Website: www.soltrek.cz
1. Introduction and important safety information
- Professional installation: This mounting system may only be installed by trained personnel with appropriate qualifications in photovoltaic system installation and construction work.
- Structural assessment and ballast: Before installation, the installation company must arrange a structural assessment of the roof's load-bearing capacity and a precise calculation of the concrete ballast required for the specific wind zone and building type. The manufacturer is not responsible for damage caused by insufficient ballast or an incorrect structural calculation.
- Roof protection: Before placing the trays, visually check that the EPDM rubber strips on the undersides of the trays are undamaged.
2. Main components
- Ballast tray: 0.8 mm thick galvanised sheet, measuring 990×685 mm, with integrated EPDM strips (30×3 mm).
- Left roof bracket (aluminium): The starting component for the East–West assembly. Exactly 2 left brackets are used at the left-hand start of each row of A-frames: one on the east-facing side and one on the west-facing side. They set the panel angle and allow the left side wind deflector to be fitted.
- Right roof bracket (aluminium): The standard intermediate and end component. Used at all remaining positions in the row, it allows the right side wind deflector to be fitted correctly at the end of the row.
- Lower connecting plate (60×40×3 mm): A thick steel component providing a rigid mechanical connection between opposing trays.
- Side wind deflector: 0.8 mm thick galvanised sheet closing the sides of the A-frame at the ends of each row.
- Solar rail (40×40 mm aluminium profile): A 3 m long support rail.
- Aluminium solar rail connector, 40×40×120 mm: An external aluminium component for rigidly joining solar rails end to end into long rows.
- Fixings: Stainless steel M8/M10 bolts for connecting trays to brackets, 40×40×3 mm square washers, self-drilling TEX screws with EPDM washers for the side wind deflectors, and panel end and mid clamps. Note: Stainless steel bolts and nuts for securing the aluminium connectors and rails to the roof brackets are also included.
3. Step-by-step installation procedure
Step 1: Position the ballast trays back to back
- Following the installation design, position the ballast trays on the roof in back-to-back pairs to form the base for the East–West panel orientation.
- Make sure all 4 integrated EPDM strips underneath each tray sit directly on the roof membrane from edge to edge (along the 990 mm length), protecting the waterproofing.
Step 2: Connect the tray to the aluminium roof bracket, connecting plate and washers
- IMPORTANT – left and right bracket arrangement: Each row of A-frames contains exactly 2 left brackets and must start with them on the left: one for the east-facing line and one for the opposing west-facing line. All subsequent positions, right through to the end of the row, use standard right roof brackets. This arrangement is essential for correctly fitting the side wind deflectors on both sides of the A-frame.
- Place the appropriate aluminium roof bracket (left or right) against the top of the ballast tray.
- Use steel M8/M10 bolts with nuts for the connection. Each tray is attached to its bracket through 2 mounting holes:
- Inner hole (where the trays meet back to back): Place the 60×40×3 mm lower connecting plate beneath this hole on the underside of the tray. It bridges the connection and rigidly joins the opposing trays together.
- Outer hole: Place a separate 40×40×3 mm square washer beneath this second hole on the underside of the tray.
- Firmly tighten all bolts using an impact wrench to form a single rigid assembly.
Step 3: Assemble the row and set the exact spacing (1650 mm)
In the same way (following Step 2), assemble the next pair of trays and brackets alongside the previous pair in the row. Position this next pair exactly 1650 mm centre to centre, measured between the aluminium brackets, from the previously assembled pair. Use a tape measure to strictly maintain this exact 1650 mm spacing between all consecutive brackets throughout the row. Correct measurement ensures the structural strength of the complete assembly.
Step 4: Add the concrete ballast
- Place standard 300×300 mm concrete paving slabs inside both prepared trays (east-facing and west-facing).
- Arrange the slabs symmetrically on both sides of each tray.
- The total number and weight of the slabs must precisely match the structural calculation and wind loading for the project so that the structure is immediately stabilised on the roof.
Step 5: Install the 3 m aluminium solar rails
- Place the 3 m long, 40×40 mm aluminium solar rails on the upper and lower bearing surfaces of the aluminium roof brackets. Install the rails in two lines, one above the other (upper and lower support lines).
- Insert M10 fixing bolts into the bottom channel of the solar rail. Pass each bolt through the hole in the roof bracket and secure it firmly from below with a nut.
- Join the individual 3 m rails into long rows using the aluminium solar rail connectors and secure them with bolts.
- Firmly tighten the entire rail structure using an impact wrench.
Step 6: Position and secure the solar panels
- Place the solar panels (for example, 1722 mm wide) on the prepared rails. Half of the panels will face east and the other half west.
- At the very beginning and end of each panel row, use end clamps to secure the panel firmly to the aluminium rail.
- Use mid clamps between adjacent panels in the row. These secure two neighbouring panels at the same time and maintain the required spacing between them.
- Firmly tighten all clamps using an impact wrench.
Step 7: Fit the side wind deflectors
- Rear wind deflectors are not installed in the East–West configuration because the structure forms a closed A-frame.
- At the ends of the rows (the left and right edges of the entire roof array), position the side wind deflectors to cover the open triangular sides of the structure: the left deflector on the left starting bracket and the right deflector on the right end bracket.
- Using an impact wrench, secure the side deflectors with self-drilling TEX screws with EPDM washers (normally 4 screws on each side of the deflector).
4. Final checks and maintenance
- After installation, check that all bolted connections are tight and that the A-frame rows are stable.
- We recommend visually inspecting the structure and checking the tightness of the connections once a year.