Cromar Hydrosil Alternative — When to Upgrade to a Premium Silicone System

If you’re currently using Cromar Hydrosil or have specified it on a past project and you’re now asking what else is out there, you’re not alone. Cromar Hydrosil is a well-established 100% silicone roof coating available through builders’ merchants across Ireland and Northern Ireland, and it does the job it was designed to do. But for a growing number of commercial projects — higher warranty tiers, occupied buildings, programme-critical refurbishments — specifiers are looking for a premium step up. This article gives you an honest comparison and helps you decide when the upgrade makes sense.

Where Cromar Hydrosil sits in the market

Cromar Hydrosil is a solvent-based, moisture-cure, 100% silicone roof coating. It’s typically applied in two coats, available in 3.78L and 18.9L packs, widely stocked and competitively priced. For small-scale repair work, builders’ merchant availability and a handful of domestic flat-roof refurbishments, it’s a legitimate product that has earned its market share.

Cromar is part of the Sika group — no small pedigree — and the product is independently tested to ASTM D6694, the recognised silicone roof coating standard. Nothing we say here should be read as a criticism of the product; we simply want to explain when a different tier of silicone makes more sense.

Where a premium silicone steps in

Commercial specifiers typically look beyond mid-market silicone products when one or more of these triggers apply:

• Warranty duration above 10 years. Mid-market silicones are typically backed by 10-year manufacturer warranties. For a large commercial asset on a 20-year hold period, a 20-year manufacturer-backed product warranty changes the lifecycle maths.
• Single-coat application. Most mid-market silicones are formulated for two-coat application. On a 5,000 m² warehouse, halving the coat count halves the labour and the exposure to Ireland’s changeable weather windows.
• Low VOC on occupied buildings. Schools, hospitals, care homes and food-processing sites often need sub-50 g/L VOC. Solvent-based silicones in the 200–400 g/L range are harder to specify in these environments.
• Class A fire certification. UL Listed Class A roofing gives specifiers a definitive fire answer; not all silicones carry this listing.
• Cool-roof performance. For energy-upgrade works, CRRC-listed and Energy Star qualified cool roofs can contribute to a building’s energy performance and its BER.
• Third-party EPD. BREEAM-rated projects need a published Environmental Product Declaration — not universal across the silicone category.

Head-to-head — Cromar Hydrosil vs GacoFlex S42

GacoFlex S42 is manufactured by Gaco (Amrize, USA), and Duratite supplies GacoFlex silicone systems in Ireland. Here’s the comparison against published data:

When Cromar Hydrosil is the right choice

Not every project needs a premium silicone. Hydrosil remains a fair choice when:

• The roof is small (under 300 m²) and low-stakes
• The contractor has existing Hydrosil familiarity and stock
• A 10-year warranty matches the client’s hold period
• Builders’ merchant availability matters more than manufacturer technical backup
• The project is domestic or light commercial, not part of a tendered spec

For those jobs, sticking with Hydrosil is entirely rational. Nothing we offer is “better” in the abstract — it’s a different tier of the same category, aimed at a different project profile.

When specifiers switch to GacoFlex S42

The typical switch triggers we see on commercial projects across Ireland and Northern Ireland:

• A tender spec requires 15+ years of manufacturer-backed warranty
• The roof exceeds 1,000 m² and single-coat labour savings are material
• The building is occupied during install (low VOC matters)
• Class A fire is specified
• The client is pursuing BREEAM or a BER-led energy upgrade
• The specifier wants direct manufacturer technical support on a large asset

Practical advice

Before committing to either product, get a free written specification. Duratite supplies free project-specific spec clauses for GacoFlex S42 within 48 hours — no obligation. If after reading the spec you decide Hydrosil or another system better fits your project, that’s fine too. We’d rather lose a job honestly than win one with the wrong product.

Ready to compare on your specific roof? Email info@duratite.ie or see the full GacoFlex S42 technical page — pricing, warranty tiers, application guide and 15 FAQs.

Cromar® and Hydrosil® are registered trademarks of Cromar Building Products (part of the Sika group). Duratite has no affiliation with Cromar. All comparisons use publicly available manufacturer data as at April 2026.