Tapered wedges & PIR boards — izoGRASS®
Unfaced PIR boards and flat roof tapered insulation (wedges). Delivery from Poland across the EU.
izoGRASS® is BOKKA’s own brand, manufactured at our facility in Wola Batorska. The line includes 2 products with a PIR core — unfaced — cut to size according to the customer’s project:
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izoGRASS® tapered wedges — PIR wedge elements for creating a slope on flat roofs (1.5–8%) without concrete screeds — reducing roof load by 80–90%. 3 layout types: unidirectional, channel, water flow. Dimensions and slope angle determined individually according to the roof design.
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izoGRASS® insulation boards — pure PIR core (unfaced). Applications: door inserts (external, garage, technical, fire-rated), strips for insulating window reveals, prefabricated elements, and insulation inside frame structures. Cut to size.
Common parameters: λD = 0.027 W/(m·K), reaction to fire class E, compressive stress ≥ 120 kPa, density 30 kg/m³ (+6/-2). Short lead time for custom orders.
Variants
izoGRASS® Tapered Wedges
PIR tapered wedges for flat roof drainage falls — BOKKA made-to-measure production.
λD = 0,027 W/(m·K)
izoGRASS® Insulation Panels
Bare PIR core for non-standard applications — in-house production by BOKKA.
λD = 0,027 W/(m·K)
Variant comparison
| Variant | Facings | Thermal conductivity (λ) | Applications |
|---|---|---|---|
| izoGRASS® Tapered Wedges | Unfaced — pure PIR core | 0,027 W/(m·K) | flat roofs (creating fall) |
| izoGRASS® Insulation Panels | Unfaced — pure PIR core | 0,027 W/(m·K) | non-standard insulation, prefabrication |
Frequently asked questions
What are tapered insulation wedges and what are they for?+
Tapered wedges are angle-cut PIR elements used to create a fall on a flat roof — without screeds or loading the structure. They ensure proper drainage (water runs to the outlets instead of ponding) while also insulating the roof. It is a lightweight, fast-to-install solution designed individually around the outlet layout.
What fall do tapered wedges provide?+
A 2% fall is the standard design (in line with flat-roof requirements), but the layout is set individually — typically from about 1.5% to 8%, with counter-falls and sumps around the outlets. Based on the roof plan and outlet locations, BOKKA prepares a wedge layout design with a parts list.
What is the unfaced PIR board (izoGRASS) and how does it differ from termPIR®?+
izoGRASS® are PIR boards cut to size, without facing — BOKKA's own production. They are used in covered/ballasted flat-roof build-ups (under bitumen felt, membrane, ballast). The lack of facing means reaction-to-fire class E and λD of about 0.027 W/(m·K). It is a different product from faced termPIR® — izoGRASS is not intended for ETICS systems or as a finishing layer.
How do tapered wedges differ from tapered PIR boards?+
Colloquially they are the same thing — tapered PIR boards, tapered wedges and tapered PIR all describe angle-cut PIR elements for a flat roof. The izoGRASS® range offers 3 wedge types (different angles and heights) combined to form the target roof fall.
Are the tapered wedges your own production and what is the lead time?+
Yes — izoGRASS® is BOKKA's own production, so the lead time is short (no waiting for an external factory), and the wedges are cut for the specific roof project. After you send the roof plan and outlet positions, we prepare the layout design, a parts list and a quote.
What roofs are izoGRASS tapered wedges suitable for?+
Flat roofs covered with bitumen felt or membrane, and ballasted/inverted roofs. They work well in renovation (correcting the fall without demolition) and in new builds. For roofs requiring a facing or a higher fire class, we will select a suitable product from the termPIR® line.