Cold Pitched Roof Construction
Tyvek® and AirGuard® membranes minimise interstitial and surface condensation in cold pitched roof construction, while helping to ensure optimal energy efficiency.
With traditional cold pitched roof construction, more insulation often means more interstitial and surface condensation, too – a danger that is aggravated by precipitation and wind. As a result, cold pitched roofs often need ventilation openings to ‘change the air’. These can reduce thermal efficiency by impairing the performance of fibrous insulation.
Tyvek® membranes are specially designed to alleviate this problem, and provide a holistic solution to cold roof constructions. They permit water vapour in the roof space to permeate through to the batten space, where the natural movement of air through the roof covering disperses it into the atmosphere. This removes the need for ventilation in the insulation – a benefit that is particularly important with cold pitched roof construction. A non-ventilated Tyvek® system will not only prevent excessive condensation but offer substantial gains in energy efficiency.
As a secondary water-shedding layer, Tyvek® membranes also provide a barrier that minimises the wind load acting on the slates and tiles, and helps keep wind-blown snow and dust out of the roof construction.
Tyvek® and AirGuard® in Cold Pitched Roof Applications
The insulation is installed at joist level, with a cold loft space (attic) between the insulation and roofing underlay. Usually, quilt insulation is laid between and over ceiling joists.
Tyvek® and AirGuard® in Room in the Roof Applications
Room in the roof constructions often use a combination of warm and cold roof constructions, with varying types of insulation. Cold roof areas usually include ‘vapour-open’ fibrous insulation (e.g., mineral wool quilt); the sloping ceiling areas include closed-cell or foil-backed rigid board insulants, most of which are highly vapour-resistant. This variation in vapour resistance can create an imbalance in vapour drive. To solve this, we recommend installing an air & vapour control layer (AVCL), such as DuPontTM AirGuard® Control, beneath the ‘vapour-open’ quilt insulation.
Meets Building Requirements
Non-ventilated pitched roof systems that use Tyvek® as rooﬁng underlay satisfy the requirement of Approved Document C2.
BBA certificate 08/4548 approves the use of non-ventilated Tyvek® systems for cold and warm pitched roof constructions. These constructions are categorised as shown; the difference lies in where the insulation is positioned.
DUPONT PRODUCTS & SERVICES
Tyvek® Supro is the market-leading breather membrane, and is a water resistant membrane suitable for all supported and unsupported pitched roof applications in commercial and residential buildings.
All Tyvek® breather membrane products
A complete listing of all Tyvek® breather membrane products
- Tyvek® AirGuard® Smart
DuPont™ AirGuard® Reflective is a low emissivity internal vapour barrier that combined with an airgap can enhance thermal comfort by reflecting up to 95% of radiant heat back into the building.
AirGuard® Reflective E
AVCL which boosts your thermal efficiency
DuPont™ AirGuard® Control is a tough, transparent vapour control barrier that improves airtightness by reducing convective heat loss and air leakage while also minimising the risk of condensation in roof and wall insulation.
Tyvek® Double-sided Tape
DuPont™ Tyvek® Double-sided Tape is an advanced sealer tape that bonds all Tyvek® membranes to smooth surfaces, and seals membrane overlaps effectively.
Tyvek® Butyl Tape
DuPont™ Tyvek® Butyl Tape provides a moisture- and airtight seal between Tyvek® breather membranes or AirGuard® AVCLs and a wide range of materials.
Tyvek® Metallised Tape
DuPont™ Tyvek® Metallised Tape is a single-sided, reflective waterproof sealing tape that seals overlaps in Tyvek® Reflex, and Air and Vapour Control Layers
Tyvek® Plastering Tape
A high performance airtight and moisture adaptive carrier tape that can be rendered. It seals difficult areas like windows, doors and timber to block connections – 1 product that fits application outside and inside.
Transparent primer that is permanently tacky after curing and with very fast curing time.
Tyvek® Acrylic Tape
DuPont™ Tyvek® Acrylic Tape is the ideal single-sided tape for repair work, or for making good around windows and pipes. It provides strong, durable bonds, and is suitable for use with most Tyvek® and AirGuard® products.
Webinar: Design Air-tight, Condensation Free Buildings
With the trend towards greater energy efficiency in buildings, as driven by Building Regulations, air tightness plays a vital role in meeting these standards. While in the past little or no attention was paid to airtightness, in recent years it has come become clear how much air tightness can contribute to the energy balance of a building.
- Tyvek® Breather Membrane Solutions
- Tyvek® Sealing Tape
- AirGuard®: Vapour Control Layer Solutions
- New Tyvek® FlexWrap EZ tape helps optimise airtightness and seal awkward areas
- Tyvek® Supro at the Jamaica Inn: Reliable resistance for a windswept cultural icon
- Lethame House aims high with DuPont membranes
- Reconstruction after the earthquake in Abruzzo
- Restoration of a architectural and cultural gem: St. Germanus church
- Tyvek® adds to the architectural wisdom of the new Liverpool Central Library
- Tyvek® helps restore the glory of historic St. Augustine’s
- XIV century St. Wenceslas Chapel is now protected with DuPont™ Tyvek® Metal advanced membrane
- DuPont™ Tyvek® is cast as a reliable performer in Poldark country
- DuPont™ Tyvek® breathes new life into heritage renovations
- Tyvek® advanced building membrane is fit for purpose at new Sports Hall
- AirGuard® Reflective achieves an air-tight seal of approval at a new Housing Association project in York
INFORMATION & IDEAS
- How to - Selecting the right vapour control and vapour barrier sealing tape for the job
- How to – Vapour control and vapour barrier installation
- What Makes a Tyvek® Watertight Breather Membrane Unique?
Underlayment: Quality and Thickness of Functional Layers Are Critical
Tyvek® membranes are proven to resist ageing better than most common multi-layer underlayments. Even after prolonged exposure to UV radiation and heat, Tyvek® underlayment stays watertight and provides superior condensation control.
- An Alternative to Multi-Layer Breathable Roofing Felt
- An Alternative to Roof Ventilation
- The Tyvek® Evolution Story
- Building In Energy Efficiency
- Tests: ventilated versus non- ventilated cold pitched roofs
- How to - Fixing the vapour barrier and vapour control membrane – timber, concrete and steelwork
Tape selection guide
Find the right Tyvek® and AirGuard® tapes and adhesive accessories for your application with our selection guide.
- How to - Install vapour control and vapour barrier membrane on down lights and ceiling hatches