Crijep, lim, sendvič: koji nosač za koju podlogu Tile, metal, sandwich: which mount for which substrate
Izbor montažnog sustava za solarne panele jednako je važan kao i izbor samih panela — pogreška u montaži može ugroziti vodootpornost krova, statiku i garaniju na panele. U ovom vodiču prolazimo kroz tri najčešće podloge s kojima se susrećemo u Hrvatskoj i koja rješenja koristimo za svaku.
1. Crijepni krov — K2 KlickFit sustav
Crijep je daleko najčešća krovišna podloga u Hrvatskoj, posebno na obiteljskim kućama iz 80-ih i 90-ih godina. Rad s crijepom zahtijeva posebnu pažnju jer je svaka krovišna kritina različita — neke se mogu ukloniti bez loma, druge zahtijevaju rezanje.
Naš standardni izbor je K2 KlickFit sustav s inox vijcima Duo za montažu na rafters (rogelji). Postupak:
- Uklanjanje odabranih krijtina na točkama montaže (1-2 komada po nosaču)
- Bušenje u rogel, aplikacija EPDM brtvila i montaža KlickFit Roof Hook
- Postavljanje krijtina natrag (ili specijalne zakrivljene krijtine za nosač)
- Montaža aluminijskih profila i klema za pričvršćivanje panela
Prednosti K2 KlickFit: modularan sustav, jednostavna izmjena komponenti, dostupnost rezervnih dijelova, usklađenost s HRN EN 1991-1-4 (opterećenje vjetrom). Nedostatak: zahtijeva pristup tavaniškom prostoru za montažu nosača.
2. Lim s stojećim šavom — svornjaci bez bušenja
Limeni krovovi s stojećim šavom (Falzziegel, Kalzip, Kingspan) sve su popularniji u modernoj gradnji i industrijskim objektima. Za ovaj tip krova standardna rješenja s vijcima nisu prihvatljiva — bušenje u lim narušava hidroizolaciju i garaniju krova.
Koristimo svornjake (clamp-on nosače) koji se hvataju za stojeći šav bez bušenja. Ključni dobavljači: Schletter S-5!, Renusol, SunModo. Svaki svornjak prihvata opterećenje do 1,5 kN po točki montaže — što je dovoljno za sve standardne solarne panele do 2,5 m² površine po ploči.
Trapeznatolimeni krovovi (bez stojećeg šava) traže drugačiji pristup: posebne brtve i vijke koji ne propuštaju vodu pri bušenju (EPDM washer vijci). Ovi krovovi su češći na industrijskim i poslovnim objektima.
„Nikada ne bušimo bez brtve i nikada ne koristimo čelične vijke na aluminijskom limu. Galvanska korozija između čelika i aluminija unijet će propuštanje u roku od 3-5 godina."
3. Sendvič paneli — nosači bez ikakvih bušenja
Sendvič krovni paneli (EPS, PIR, kamena vuna između dvaju limenih ploča) su dominantna podloga na industrijskim halama i modernim poslovnim objektima. Specifičan izazov je mala nosivost površine panela — tanka čelična ploča između izolacije ne može primiti točkasto opterećenje bez deformacije.
Rješenje su aerodinamični nosači bez bušenja (Renusol ConSole+, K2 CrossRail) koji se postavljaju direktno na površinu sendvič panela i koristite vlastitu masu i aerodinamičan profil za stabilizaciju. Masa sustava (beton balasti + metalni profili) osigurava otpornost na podizanje vjetrom, bez jedinog vijka u krovnu podlogu.
Uvjet za ovu metodu: minimalni nagib krova za odvod vode je 1,5° (preporučen 3°+), i statičar mora verificirati da sendvič panel može podnijeti raspoređeno opterećenje od 15-25 kg/m² od sustava.
Opterećenja vjetrom i HRN EN 1991
Bez obzira na vrstu krova, svaki montažni sustav mora biti dimenzioniran prema HRN EN 1991-1-4 (Eurokod 1: opterećenje vjetrom). Za Hrvatsku, zona vjetra varira od Zona 1 (Slavonija, Zagreb)** do **Zona 5 (Jadran, otoci)** — razlika u referentnom dinamičkom tlaku je 2-3 puta.
Naša praksa: za sve objekte u priobalnom pojasu (100 km od mora) zahtijevamo projektni proračun nosača u skladu s EN 1991-1-4, uključujući topografski koeficient i koeficient izloženosti. Za kontinentalne lokacije s godišnjim vjetrom ispod 90 km/h koristimo tablične vrijednosti preporučene od proizvođača (K2, Schletter).
The choice of mounting system for solar panels is as important as the choice of panels themselves — installation errors can compromise roof waterproofing, structural integrity, and panel warranties. In this guide we walk through the three most common substrates we encounter in Croatia and the solutions we use for each.
1. Tiled roof — K2 KlickFit system
Tiles are by far the most common roof substrate in Croatia, especially on family homes from the 1980s and 90s. Working with tiles requires special care because each tile type is different — some can be removed without breaking, others require cutting.
Our standard choice is the K2 KlickFit system with stainless steel Duo screws for mounting on rafters. Procedure:
- Remove selected tiles at mounting points (1-2 per bracket)
- Drill into rafter, apply EPDM sealant, and mount KlickFit Roof Hook
- Replace tiles (or use special curved tiles for the bracket)
- Install aluminium rails and panel clamping brackets
K2 KlickFit advantages: modular system, easy component replacement, spare parts availability, compliance with HRN EN 1991-1-4 (wind loading). Disadvantage: requires access to loft space for bracket installation.
2. Standing seam metal roof — no-drill clamps
Standing seam metal roofs (Falzziegel, Kalzip, Kingspan) are increasingly popular in modern construction and industrial buildings. For this roof type, standard screw solutions are not acceptable — drilling into the sheet metal compromises waterproofing and the roof warranty.
We use clamp-on mounts that grip the standing seam without drilling. Key suppliers: Schletter S-5!, Renusol, SunModo. Each clamp accepts loads up to 1.5 kN per mounting point — sufficient for all standard solar panels up to 2.5 m² surface area per module.
Trapezoidal sheet metal roofs (without standing seam) require a different approach: special EPDM washer screws that don't leak when drilling. These roofs are more common on industrial and commercial properties.
"We never drill without a washer and we never use steel screws on aluminium sheet. Galvanic corrosion between steel and aluminium will cause leaks within 3-5 years."
3. Sandwich panels — zero-penetration ballasted mounts
Sandwich roof panels (EPS, PIR, or mineral wool between two metal sheets) are the dominant substrate on industrial warehouses and modern commercial buildings. The specific challenge is the low load-bearing capacity of the panel surface — the thin steel sheet between insulation layers cannot accept point loads without deformation.
The solution is aerodynamic ballasted mounts (Renusol ConSole+, K2 CrossRail) placed directly on the sandwich panel surface and using their own weight and aerodynamic profile for stabilisation. The system weight (concrete ballast + metal profiles) ensures wind uplift resistance, without a single screw in the roof substrate.
Conditions for this method: minimum roof slope for drainage is 1.5° (3°+ recommended), and a structural engineer must verify that the sandwich panel can support a distributed load of 15-25 kg/m² from the system.
Wind loads and HRN EN 1991
Regardless of roof type, every mounting system must be dimensioned to HRN EN 1991-1-4 (Eurocode 1: wind loading). For Croatia, the wind zone ranges from Zone 1 (Slavonia, Zagreb) to Zone 5 (Adriatic, islands) — the difference in reference dynamic pressure is 2-3 times.
Our practice: for all properties in the coastal belt (within 100 km of the sea) we require a structural calculation of mounts in accordance with EN 1991-1-4, including topographic coefficient and exposure factor. For inland locations with annual wind speeds below 90 km/h we use the tabular values recommended by the manufacturer (K2, Schletter).