Everything you need to specify and build a ballasted or bracketed PV mount for a flat commercial roof, a garage, an outbuilding, or an off-grid ground array — using Fastensol and Renusol hardware in stock at AIZO Quality Heating. Includes an interactive kit builder that picks the parts and quantities for your specific panel count.
Why flat roof mounting is different
A "flat" roof is rarely dead-level — most have a 1° to 5° fall for drainage — but for solar purposes anything below about 10° counts as flat. That geometry changes almost every decision compared with a pitched roof install: you can't hook onto tiles or slates, the panels need artificial tilt to reach a useful angle, and the wind acts on the array in a very different way (uplift and drag on the exposed rear face instead of pressure across the plane).
Three problems have to be solved by the mounting kit:
- Tilt. A panel laid flat in the UK loses roughly 10–15% of its annual yield versus one at 30°, and rain won't self-clean it. Flat roof mounts introduce a fixed tilt — commonly 10°–15° for commercial rows or 30° for smaller domestic and marine arrays.
- Wind resistance. A tilted panel is essentially a sail. The system must either be bolted through the roof deck (fixed) or held down by ballast weight (usually paving slabs) that exceeds the design uplift force for the site.
- Membrane protection. Flat roofs are waterproofed with felt, EPDM, TPO, PVC, single-ply or asphalt. Penetrating every fixing point voids most warranties, so ballasted "penetration-free" solutions dominate the market.
Rule of thumb. If the roof is under 15 years old and the membrane warranty matters, choose a ballasted system (Fastensol Flat Roof Tray, Renusol ConSole+, or Renusol ECO Ballast Set). If the deck is timber or profiled metal and you're happy to seal a small number of fixings, a bracket-and-rail system is stiffer and lighter.
Ballasted vs fixed (penetrating) systems
Almost every flat roof product on the AIZO mounting collection is one of two designs. Understanding the trade-off before you start pricing components will save a lot of returns.
Ballasted (non-penetrating) trays and tubs
The panel sits on a plastic or aluminium tray. The tray is loaded with concrete paving slabs (typically 40 mm × 400 mm × 400 mm) until the total weight resists the design wind uplift. There are no fixings through the membrane. Fastensol's ballast tray and Renusol's ConSole+ are the two dominant options in this shop. The trade-off is weight: a fully-loaded ConSole+ can add 40–80 kg per module to the deck load.
Fixed brackets on penetrating fixings
An aluminium H-profile or VarioSole rail is bolted through the deck into the timber or steel structure, with a flashed and sealed penetration at each foot. Fastensol's Triangle Bracket (MPTB-GS) or Renusol's TriSole+ L-Profile provide the 30° angle. The trade-off is waterproofing risk — done well it lasts decades, done poorly it leaks in the first season.
Hybrid (ballast + tie-down)
On coastal or high-rise sites where pure ballast would need 200 kg+ per corner, installers use ballast for the middle rows and a small number of tie-down anchors at the edges. This is the standard commercial approach above about 20 m building height.
Anatomy of a flat roof mount
Every ballasted or bracketed flat-roof array is assembled from six part families. Knowing the vocabulary makes it much easier to build a bill of materials.
Tray or tub
The load-bearing base that either holds ballast (ConSole+, Fastensol Tray) or connects to the roof deck.
Rails
Aluminium extrusions (H-profile, silver rail, VarioSole 41×35 or 50×37) that the modules clamp onto.
Triangle brackets or L-profiles
Set the tilt angle — Fastensol MPTB-GS (30°) or Renusol TriSole+ L-profile sets.
End clamps and mid clamps
Grip the module frame to the rail. Sized to your frame thickness (30 mm and 35 mm are the UK standards).
Rail connectors and cross-connects
Splices for long runs, cross-connects for perpendicular joints (e.g. Fastensol FS-Hex-nut).
Fixings, bolts & sealants
M8 T-nuts, hex bolts, hanger bolts, plus marine-grade sealants like C-Tec CT1 for bonded and penetration-sealed installs. Small parts, but the whole array relies on them.
The Fastensol range
Fastensol is a UK-focused range with a lightweight aluminium tray system that suits residential, garage and small commercial flat roofs, plus a 30° triangle bracket for panels mounted on rails. The full Fastensol catalogue in stock:
Flat roof trays and brackets
Flat Roof Tray Kit (Landscape) — 30 mm clamps
Ballasted aluminium tray for landscape-mounted framed panels with 30 mm frame thickness. Suits garage, outbuilding and ground-mount use.
Flat Roof Tray Kit (Landscape) — 35 mm clamps
Same aluminium tray sized for the more common 35 mm framed modules used by JA Solar, Jinko, Longi and DMEGC at typical Wp ratings.
Flat Roof Tray (Landscape, Extended)
Extended version for wider panels up to 1140 mm. Use when your module frame won't fit the standard tray footprint.
Triangle Bracket MPTB-GS (30° portrait)
Fixed 30° triangle bracket for portrait modules on flat roofs and ground mounts. Pairs with the 3300 mm H-profile rail for a fully engineered install.
Rails, clamps and small parts
3300 mm H-Profile Rail
Aluminium H-profile rail — the backbone for Triangle Bracket builds and bespoke mounting projects.
3550 mm Silver Rail
Longer aluminium mounting rail for pitched and flat roof PV systems where the standard 3300 mm won't span the layout.
Black End Clamp 30 mm
MCS-certified end clamp for 30 mm framed modules. Black anodised for a matched all-black install.
Cross Connect with Hex Nut
Perpendicular rail fixing for triangle brackets and standing-seam hooks. Joins two rails at 90°.
H Rail Splice
Joiner for creating longer runs from two H-profile rails when a single 3300 mm length is too short.
Rail Bolt M8 (T-Nut)
Roof hook and accessory fixing for the Fastensol solar rail. Slides into the rail channel.
The Renusol range
Renusol is the German engineered solution — the ConSole+ polymer tub is one of the most specified ballasted mounts in Europe, and the ECO Ballast Set gives a rail-based penetration-free alternative for larger arrays. Both come with published wind-load and ballast calculators, which makes them the natural choice for commercial and installer specifications.
ConSole+ ballasted tub system
ConSole+ Kit — including mounting material & U-profile
The complete ballasted flat roof and ground mount kit. Recycled polymer tub with integrated U-profile — accepts one framed 60/72-cell module. Currently 16% off.
Mounting Material for ConSole 4.1, 4.2, 5.2, 6.2, CS+
Replacement or supplementary fixing set for ConSole tubs. Use when you're extending an existing installation.
ConSole Elongation Rails XL (pair)
Extension rails for the ConSole 4.1, 4.2, 5.2, 6.2 and CS+ — take a larger module frame or link tubs.
ECO ballast, TriSole+ frames and clamps
ECO Ballast Set FS 2100 mm
Penetration-free rail-based ballast system for flat roofs, 2100 mm module class. Alternative to the ConSole+ tub for larger arrays.
TriSole+ L-Profile Cross Striving Profile SET
L-profile cross-strut kit for building pitched or flat-roof tilt frames — the Renusol equivalent of a triangle bracket assembly.
TriSole+ L-Profile LONG 1900 mm (Bifacial)
The long 1900 mm variant of the TriSole+ cross-strut, specified for bifacial modules where extra clearance improves rear-side yield.
End Clamp+ 30–50 mm (Black/Silver)
Universal end clamp for any framed module from 30 mm up to 50 mm thick. Choose the anodised colour to match your rail.
VarioSole+ Mounting Rail 50 × 37 (up to 4800 mm)
High-load 50 × 37 aluminium PV rail — the workhorse for larger commercial arrays and long spans. Available in silver or black.
VarioSole+ Mounting Rail 41 × 35 × 3600 mm
The lighter, standard-load VarioSole+ rail for pitched and tilted flat-roof mounting.
Renusol's UK range also includes a wide catalogue of roof hooks, hanger bolts, wood screws, storm washers and MetaSole+ metal-roof anchors. See the full Renusol Mounting Equipment collection for slate, pantile and trapezoidal-metal fixings you'll need if the same job spans a mixed roof structure.
Side-by-side comparison
The two brands overlap on paper but suit different jobs. Read this table before committing to a system for a whole array.
| Feature | Fastensol Tray | Renusol ConSole+ | Renusol ECO Ballast | Fastensol Triangle Bracket |
|---|---|---|---|---|
| Type | Ballasted aluminium tray | Ballasted polymer tub | Ballasted rail system | Fixed 30° bracket on rails |
| Roof penetration | No | No | No | Yes (bolt-through) |
| Typical tilt | ~10° | ~10° | ~10° | 30° |
| Best for | Single panels, garages, sheds | Commercial 60/72-cell arrays | Large commercial rows | Domestic ground mount, higher winter yield |
| Frame thickness | 30 mm or 35 mm variant | Universal U-profile | 30–50 mm via End Clamp+ | 30 mm via Fastensol clamp |
| Ballast required | Yes (slabs) | Yes (slabs / gravel) | Yes (slabs) | None |
| Cost per panel (kit) | £29.95–£59 | £79.95 | £49.95 | ~£65 (bracket + rail) |
| Best-in-class for | Low weight, single-panel jobs | Engineered commercial spec | Bifacial & large modules | Off-grid, 30° optimisation |
Ballast weight is your headline number. A ConSole+ can require 60 kg+ of paving slabs per panel in exposed sites. Always confirm your flat roof deck can carry the total dead load (array + ballast) plus the live load (snow, maintenance access) before ordering. Older commercial felt roofs on lightweight steel deck often can't.
Special case: Fastensol Narrow Boat Tilt Mount
Fastensol Semi-Permanent Adjustable Tilt Mounting Set — Narrow Boats
Not every flat surface is a building. UK canal boats and narrowboats have a broadly flat cabin roof that behaves very differently from a house — the boat rotates in the water as it moors, so an array fixed to a single orientation is only aligned to the sun for half the time. Fastensol's Narrow Boat Tilt Mount is engineered specifically for this problem, and it's the reason this product sits in the flat roof mounting family rather than the domestic solar range.
Why it exists — the situations it solves
Boaters live off-grid or semi-off-grid on 12 V or 24 V systems. Solar is the primary way to keep leisure batteries topped up between engine runs. The problems the mount solves:
- Mooring changes. When you move to a new mooring, the boat might now face north-east instead of south-west. The telescopic tilt legs let you flip the panel from port to starboard in seconds — the array can always be angled toward the sun regardless of which way the boat is moored.
- Bridge and tunnel clearance. Under way, you need a low profile so you can clear low bridges and don't create windage that pulls the boat off course. The same legs fold the panel flat against the roof, so sightlines from the tiller stay clear.
- Marine environment. Rails and legs are AL6005-T5 aluminium — the same alloy used in yacht spars — chosen for corrosion resistance in a permanent waterway environment.
- Winter tilt. UK winter sun sits at ~15° elevation. A near-flat panel produces almost nothing in December. Tilting to 30°–45° can double December output, which is the difference between running lights and heating in a liveaboard scenario.
Typical situations this product suits: continuous cruisers on the Grand Union, Kennet & Avon or Leeds & Liverpool; liveaboards with a 300–500 W solar array powering a Victron or EcoFlow off-grid setup; hire boat fleets specifying a flip-tilt array for guest reliability; small motor cruisers with a flat coachroof.
Fixing note for boats. The tilt legs are through-bolted and bonded to the roof surface — this is a semi-permanent fixture, not a portable mount. We stock C-Tec CT1 TRIBRID sealant for this exact job — it cures under water, bonds to all metals including lead, has excellent UV resistance for years of exposed marine service (-40°C to +120°C), and is available in black, anthracite or grey to match the aluminium rails. Two 290 ml cartridges typically cover a single-panel install. Fixing screws and rubber isolation pads still need to be selected for your specific deck thickness and material.
Interactive kit builder
Tell the tool how many panels you're mounting, which mounting style you prefer, and your panel frame thickness. It will generate a full bill of materials with quantities and total cost, using in-stock Fastensol and Renusol parts. Every part links straight to its product page on qualityheating.co.uk.
Flat Roof Mounting Kit Builder
Estimator only — always confirm ballast requirements with the manufacturer's wind-load calculator for your site.
Your bill of materials
Select your options — the parts list will appear here.
Installation and roof-load considerations
Even a perfect bill of materials is worthless if the roof can't take the load. Before ordering any flat-roof mounting kit:
- Structural survey. Get a chartered surveyor or structural engineer to sign off the deck's dead-load capacity. Modern warehouse roofs typically carry 60–90 kg/m². Older commercial felt roofs on lightweight steel deck can be far less.
- Wind zone. Postcode determines your wind zone under BS EN 1991-1-4. Coastal and elevated sites need considerably more ballast — Renusol and Fastensol both publish site-specific calculators.
- Membrane condition. Even non-penetrating ballasted systems concentrate load at their contact points. Add a protective slip mat (typically 3 mm EPDM) between the tray and the membrane on TPO, PVC and modified bitumen roofs.
- Access and edge zones. UK Working at Height regulations require an edge protection strategy for any roof array. Leave a 500 mm walkway around the perimeter of the array, plus space for the inverter, isolators and DC combiner.
- Cable management. Route solar DC cables through UV-stable trunking, not zip-tied to the tray edges. Every clip and cable tie fails eventually in UK weather.
- MCS certification. If the install is grid-connected and claiming the Smart Export Guarantee, the mounting system must be MCS-approved. Fastensol clamps are certified; the Renusol ConSole+ system carries MCS approval for its published configurations.
For a full BOM including panels, inverters and batteries, take a look at our Solar Bundles, browse solar panels, and check off-grid solar kits if the array is for a boat, caravan or remote cabin.
Frequently asked questions
Do I need planning permission for a flat roof solar array in the UK?
For domestic and most commercial buildings in England, flat roof solar under 1 m above the roof plane is permitted development. Listed buildings, conservation areas, and sites within an AONB usually need consent. Always check with your local planning authority before ordering hardware.
How many paving slabs do I need for a ballasted mount?
Between 2 and 6 standard 40 mm × 400 mm × 400 mm concrete slabs per panel is typical for the UK. Exact quantity depends on wind zone, building height, panel size and the manufacturer's calculation. Renusol's online ConSole+ configurator will output the exact number for your postcode.
Can I mix Fastensol and Renusol components?
Not recommended — clamp channels, T-nuts and rail profiles are not cross-compatible. Choose one brand for the mechanical assembly. You can, of course, mix brands across the wider system: Renusol trays with a JA Solar panel, a Victron inverter and a Fox ESS battery is a perfectly normal spec.
What tools do I need to install a flat roof kit?
A torque wrench with 6 mm and 8 mm hex sockets is essential — the clamp torque figures (typically 14–20 Nm) must be respected or the panel frame can crack. Also useful: a rubber mallet, a spirit level, a chalk line for setting out rows, and a lifting strap or two-person lift for larger 500 W+ modules.
Do you offer trade or bulk pricing on Renusol and Fastensol?
Volume and project-based quotes are handled case-by-case — for larger orders or repeat installer accounts, request a bespoke quote via our quote page and we'll come back with pricing tailored to your project. If you install regularly and would rather earn recurring revenue than negotiate one-off pricing, the AIZO Partner Program pays commission on every referred sale — often more valuable long-term than a single discount, especially if you're specifying kit for clients who buy their own hardware.
Are these components covered by warranty?
Yes. Renusol offers a 10-year product warranty on its ConSole+ and VarioSole+ systems. Fastensol aluminium components carry a 10-year corrosion warranty. Warranty is void if the installation exceeds the published maximum wind or snow-load ratings for your zone.
Last reviewed and updated: . Pricing and specifications are subject to change — always check the linked product page for current values.
Building a larger commercial array?
For arrays above 20 panels or MCS-certified installer specifications, our solar team will produce a full bill of materials with wind-load calculations, delivery scheduling and project pricing.
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