Mineral Wool
From flat board to precision-cut tapered schemes, Gradient UK specifies, supplies, and supports every stage of your roofing project - backed by free design and U-value calculations.
What is mineral wool?
Mineral wool is produced from either rock wool (stone wool) or glass wool and is one of the most trusted insulation materials in the UK roofing industry. Manufactured by melting naturally occurring rock or recycled glass and spinning it into fine fibres, the resulting product is dense, resilient, and dimensionally stable.
In flat and tapered roof applications, mineral wool boards are specified where non-combustibility is paramount. Mineral wool achieves an Euroclass A1 fire rating and will not contribute to the spread of flame - a critical consideration under current UK Building Regulations and the post-Grenfell reform landscape.
Gradient UK's mineral wool systems are compatible with all major waterproofing membranes and structural deck types, including concrete, profiled steel, and timber.
Why mineral wool?
Non-Combustible
Euroclass A1 — will not ignite, spread flame, or generate toxic smoke
Moisture Resistant
Hydrophobic treatment prevents water absorption without compromising breathability
Thermal Performance
λ values from 0.033 W/mK — high R-values achievable at practical thicknesses
Acoustic Control
Excellent airborne and impact sound attenuation for urban buildings
Sustainable
High recycled content, inert at end of life, low embodied carbon
Dimensionally Stable
Does not creep or settle under compressive load over decades of service
Flat & Tapered Roof Systems
Flat Roof Insulation
A continuous, level mineral wool board system installed above the structural deck. Ideal for roofs with pre-formed falls or where drainage is achieved by the deck profile itself.
- Single or dual-layer board configurations
- Compatible with warm roof and inverted roof principles
- Available in mechanically fixed and adhered build-ups
- Thicknesses from 50mm to 200mm, to meet Part L targets
- Suitable for all deck types: concrete, steel, timber
- Can be overlaid with protection board or used as substrate for single-ply
Tapered Insulation Schemes
bespoke engineered system using variable-thickness mineral wool boards to create positive falls towards outlets - eliminating standing water without altering the structural slab level.
- Gradient design service: we produce a full cutting plan to your drawings
- Falls as low as 1:80 achievable with precision-cut boards
- Ridge, valley, and cricket (saddle) configurations
- Minimises structural loading compared to screed-to-fall
- Reduces ponding and the associated membrane degradation
- Compliant with BS 6229 and NHBC roof drainage guidance