Glassine

Pergamin is an uncoated roll material made of roofing cardboard saturated with petroleum bitumen. It is used as an underlay in a roofing membrane, as vapor and waterproofing of building structures, and as a protective wrap for pipeline thermal insulation. Unlike mineral-surfaced roofing felt, pergamin has no coarse granule cap sheet, so it is not used as a UV-exposed finish layer.

This product group commonly includes grades based on cardboard density (such as P-250, P-300, P-350). Typical rolls are about 1 m wide with an area of 20 or 40 m². Exact characteristics depend on the manufacturer, size and design and must be checked against the datasheet of the specific product. The material is light, flexible and easy to install: sheets are laid with an overlap and joints are sealed with bitumen mastic.

P-300 Glassine — Rolled Roofing and Sealing Material

P-300 glassine is a rolled roofing and sealing material manufactured in accordance with GOST 2697-83. It is made from a special cardboard base impregnated with petroleum bitumen. The material is used as an underlay for roofing systems, as waterproofing in building structures, and as a protective layer between wood and metal.

The category includes rolls measuring 1 m in width and 20 m in length. The material is dark brown and has a smooth, unsurfaced finish.

Applications

Roofing underlay — installed beneath roofing felt or torch-on roofing materials as a primary waterproof barrier.

Waterproofing for building structures — protects foundations, plinths, and partitions against capillary moisture.

Protective layer between wood and metal — used around embedded components, supports for timber structures, and wherever wooden joists come into contact with concrete or metal. It helps prevent wood decay.

Protection of timber structures — installing glassine between a wall and a window frame or between a wall and rafters is a simple, proven way to extend the service life of timber.

Specifications

Grade P-300 — the number indicates the weight of the cardboard base per square metre: 300 g/m².

Roll size: 1 × 20 m.

Roll area: 20 m².

Thickness: 0.4–0.5 mm.

Flexibility over a bar with a radius of 25 mm at a temperature not exceeding +5 °C.

Water absorption after 24 hours: no more than 20% by weight.

The estimated service life as a roofing underlay is 5–7 years. When used as a waterproofing layer inside concealed structures, the material may last considerably longer.

Frequently Asked Questions

What is the difference between glassine and roofing felt?

Glassine is cardboard impregnated with bitumen, without an external protective coating or mineral surfacing. Roofing felt consists of cardboard with bitumen treatment on both sides and an outer protective layer of mineral or slate granules.

Glassine is thinner and more economical. It is used as an underlay beneath roofing felt or as waterproofing in concealed areas. Roofing felt can be used as a standalone roofing material and can withstand exposure to sunlight and precipitation. Unprotected glassine deteriorates quickly when exposed to outdoor conditions.

Can glassine be used as the only roofing layer?

No. Glassine is designed to be installed beneath a protective layer. Without a top covering, ultraviolet radiation, temperature fluctuations, and precipitation will cause it to deteriorate within one or two seasons. Roofing felt or a torch-on membrane should be used for a single-layer roofing system.

Is glassine suitable for foundation waterproofing?

Yes. It can be used as an economical option in residential construction. The material is installed between concrete and the bottom course of a log structure or between the foundation and the plinth.

For permanent waterproofing of below-ground structures in modern buildings, torch-on membranes and liquid-applied waterproofing compounds are normally used. These materials are more durable and provide a continuous protective coating.

In pipeline systems, pergamin is used as a moisture barrier around insulation half-shells and segments in ducts, trenches, basements and attics, where condensate and ground moisture must be kept away from the insulation. When selecting a product, consider the grade, roll area, installation conditions and compatibility with adjacent insulation layers.

You can order pergamin with delivery across Ukraine. Confirm the required grade and footage before purchase so the material can be matched to roofing, structural waterproofing or pipe-insulation protection.