DuPont's Tyvek

Protects buildings and their occupants through the use of its unique and highly advanced technological material, Tyvek®. At the same time DuPont products protect the environment for future generations, as Tyvek® roofs and walls are extremely efficient - cutting energy consumption, heating bills and greenhouse gas emissions to the atmosphere, and thus reducing the risk of global warming.

DuPont has an outstanding track record as a strong and reliable manufacturer with a long standing commitment to sustainable growth, meeting the specific needs and requirements of all customers, such as architects, specifiers, builders, roofing contractors, etc.

Unique technology is used to create the fibre structure of Tyvek®.

Backed by more than 30 years experience worldwide it ensures superior durability and long term performance which provides the following benefits:

Tyvek® is the only product with a unique functional layer that is entirely made up of millions of unique micro fibres. These are bonded together to create a maze that stops water penetrating, whilst allowing water vapour to freely move through the fibres (pores).

Moisture management and protection from the external elements

Minimises air and water ingress, whilst allowing moisture to migrate freely and safely into the atmosphere as required in Building Regulations/Standards (Tyvek® high vapour permeability).

Helps minimise condensation to protect the building structure, preserve the integrity of the insulation material and thus its performance and provides a healthy indoor climate.

Energy efficiency

Helps to reduce energy loss due to uncontrolled air infiltration (Tyvek® air tightness). The new generation of metallised membranes reflect the heat inside the building during winter leading to increased energy savings (Tyvek® low emissivity). Helps to minimize CO2 emissions by reducing energy consumption.

Comfort

Tyvek® membranes control the movement of heat, air and moisture in a building by minimising air leakage and therefore allowing greater environmental control to the occupants. The new generation of metallised membranes helps to reflect external heat during the summer.

Building regulations compliance

Tyvek® membranes help to satisfy items a, b & c of Approved Document C(2) for England & Wales and Sections 3.10 and 3.15.4 of The Scottish Building Standards – Resistance to moisture/Precipitation and Interstitial condensation

Tyvek® membranes also assist in satisfying Approved Document L for England & Wales and Section 6.2.5 of the Scottish Building Standards – Air permeability/Air infiltration

Tyvek® metallised membranes further assist in Part L and Section 6.2 compliance by improving thermal performance.

Certified and durable materials

UV and heat stability ensure long term performance. CE marking and warranties available. In the event of a fire, Tyvek® membranes will not give off any harmful gasses.

Tyvek® Supro

The market leading vapour permeable roofing underlay: an extremely water-resistant, airtight and vapour open membrane.

More Energy Efficiency For Less Roof Ventilation

Tyvek® Supro is an extremely water resistant, airtight and vapour permeable membrane providing superior air and 0moisture management for commercial and residential buildings.

Tyvek® Supro is a multi-purpose, durable and reinforced Tyvek® grade for use in all supported and unsupported pitched roof applications, including warm, hybrid and cold roofs.

Also suitable for Scottish sarking board systems and low pitched metal roofs as well as wall and floor applications.

Product Properties

Composition: Spunbonded polyethylene and polypropylene

Roll Size 1.5m x 50m; Weight 12kg; Coverage 67.5m2

Roll Size 1.5m x 50m; Weight 8.5kg; Coverage 42.5m2

UV exposure 4 months

Warranty 30 years

Description

Tyvek Supro is vapour permeable and manufactured by spinning strands of high-density polyethylene (PE-HD) and bonding them together with heat and pressure to form a flexible sheet.

Tyvek Supro is available with or without an integral adhesive tape (see Tyvek Supro Plus below).

The product has the nominal characteristics of ...

Thickness (mm) 0.45

Mass per unit area (gm–2) 145

Roll length (m) 50 - Roll width (m) 1.0, 1.5

Tensile strength (N per 50 mm) longitudinal >400 transverse >400

Elongation at break (%)(1) longitudinal 17 transverse 17

Colour white underside/ grey top side and red logo

General

Tyvek Supro Roof Tile Underlay must be installed and fixed in accordance with the BBA Certificate No. 08/4548

Installation can be carried out under all conditions normal to roofing work.

The product is installed with the printed side uppermost and lapped to shed water out and down the slope.

Overlaps must be provided with the minimum dimensions given in the table below

In closed eaves constructions, eaves guards should be used to protect the product from sunlight and direct water into the gutter. Tyvek Eaves Carrier is recommended by the manufacturer for this purpose.

Hips should be covered with a 600 mm wide strip of the product.

Weathertightness

Tests indicate that the product will resist the passage of water, wind-blown snow and dust into the interior of a building, under all conditions to be found in a roof constructed in accordance with the relevant clauses of BS 5534 : 2003.

The product resists penetration of liquid water and consequently may be used as temporary waterproofing prior to the installation of slates or tiles. The period of such use should, however, be kept to a minimum.

Risk of condensation

For design purposes, the product’s water vapour resistance may be taken as not more than 0.25 MNsg–1 and for roofs designed in accordance with BS 5534 : 2003 or BS 5250 : 2002, Section 8.4, it may be regarded as a Type LR membrane.

In common with all roofs, care must be taken in the overall design and installation to minimise the risk of water vapour coming into contact with cold parts of the construction. Factors to be considered and minimised include, moisture diffusion through the ceiling, infiltration through unsealed openings/penetrations in the ceiling and services evaporating or venting moisture into cold spaces.

The risk of condensation is highest in new-build construction during the first heating period, where there is high moisture loading due to wet trades, such as in-situ cast concrete slabs or plaster.

The risk of condensation diminishes as the building naturally dries out. See BBA Information Bulletin No 1 — Roof Tile Underlays in Cold Roofs during the Drying-out Period. Ceiling and insulation horizontal (cold ventilated roof)

Roofs designed and constructed in accordance with BS 5250 : 2002 will adequately limit the risk of interstitial condensation. Ceiling and insulation inclined (warm roof)

For roofs with an insulated inclined ceiling, ventilation above or below the underlay will not be required provided that the passage of moisture by diffusion and by convection is controlled, eg, by a vapour control layer (eg TYVEK SD2) or a continuous envelope of insulation with a high vapour resistance. Ceiling and insulation partially inclined (warm roof and cold roof)

Where an insulated ceiling only spans part of the roofline, resulting cold roof spaces should be installed in accordance with Product Sheet 2 of this Certificate.

Wind loading

Project design wind speeds should be determined and wind uplift forces calculated, in accordance with BS 6399-2 : 1997.

The product, when fully supported, has adequate resistance to wind uplift forces. 7.3 For a cold ventilated system, wind loading on the underlay should be calculated in accordance with BS 5534 : 2003, Section 5.5.2.7. For acceptable wind loads with specific batten spacings for the draped product, using a 25 mm deep tiling batten (see section 16, Table for Physical properties — general).

Strength

The product will resist the loads associated with installation of the roof (See BBA Certificate Section 16, Table for Physical properties — directional).

Properties in relation to fire

The product will melt and shrink away from heat, but will burn in the presence of a naked flame. The product is classified in accordance with BS EN 13501-1 : 2007 as a Class E material.

When the product is used unsupported, there is a risk that fire can spread if it is accidentally ignited during maintenance works, eg by a roofer’s or plumber’s torch. As with all types of underlay, care should be taken during building and maintenance to avoid the material becoming ignited.

When the product is used in a fully supported situation, the reaction to fire will be determined by the support.

Maintenance

As the product is confined within a roof structure and has suitable durability maintenance is not required.

Durability

The product will be virtually unaffected by the normal conditions found in a roof space and will have a life comparable with that of traditional roof tile underlays, provided they are not exposed to sunlight for long periods (see section 12.4). Advice regarding exposure can be obtained from the Certificate holder. Installation

Installation

Tyvek Supro Roof Tile Underlay must be installed and fixed in accordance with the Certificate holder’s instructions, provisions of this Certificate and the relevant recommendations of BS 5534 : 2003 and BS 8000-6 : 1990.

Installation can be carried out under all conditions normal to roofing work.

The product is installed with the printed side uppermost and lapped to shed water out and down the slope.

Overlaps must be provided with the minimum dimensions given in Table 1.

In closed eaves constructions, eaves guards should be used to protect the product from sunlight and direct water into the gutter.

Tyvek Eaves Carrier is recommended for this purpose.

Hips should be covered with a 600 mm wide strip of the product.

Procedure

Fully supported

The product may be used over sarking boards of softwood (cold ventilated roofs), and either with continuous insulation or insulation placed between the rafters (warm roofs).

The product is either secured to the support with counter battens at least 12 mm thick to create a drainage and vapour dispersal space between the product and the tiles or, when using timber sarking, the traditional Scottish practice with the tiles or slates fixed directly into the boards. This space should be ventilated in accordance with BS 5250 : 2002 when using tight fitting roof covering.

Counter battens, when used are fixed with corrosion-resistant staples or galvanized clout nails as appropriate. Tiling battens are secured to the counter battens and support fixings. Alternatively, the membrane may be installed draped over counter battens, with sufficient drape to allow drainage of liquid water under the tiling battens.

Care must be taken to minimise the risk of interstitial condensation as described in section 6.5 particularly for timber sarking which may be below the dew-point for extended periods during winter months.

Unsupported

The product, when installed as an unsupported system, is fixed in the traditional method for roof tile underlays, ie draped between the rafters.

Repair

Damage to the product can be repaired easily prior to the installation of slates or tiles by replacing the damaged areas, by patching and sealing correctly. Care should be taken to ensure that the watertightness of the roof is maintained.

Finishing

Detailing of abutments, verges and hips must be in accordance with the Certificate holder’s instructions.

The tiling and slating must be carried out in accordance with the relevant clauses of BS 5534 : 2003, BS 8000-6 : 1990 and the tile/slate manufacturer’s instructions, especially when using tightly-jointed slates or tiles.

Manufacturer

Du Pont (U.K.) Limited, Wedgwood Way, Stevenage, Herts SG1 4QN
Tel: +44 (0) 1438 73 4000 Fax : +44 (0) 1438 73 4836

Page last updated Tuesday, June 1, 2010