It's Airtight Outside
The Problem - In many constructions, about half of all heat loss is due to air leakage through the building. Given that approximately half of all energy used in the UK is from buildings, it is easy to see that air leakage, or draughts, account for a
considerable amount of energy - and therefore cost.
As thermal insulation requirements have increased over the last few years, the proportion of energy lost through air leakage has become more evident. The ever-increasing thermal insulation required will however be rendered largely ineffective unless
the airtightness of the structure itself is addressed. Tests indicate that air leakage can reduce the effectiveness of thermal insulation by up to 70%; therefore if energy efficiency is to be improved within buildings, this is the most critical area
to focus on.
In addition to improved insulation, energy efficient heating systems will also be ineffective if warm air can escape the building and cold air can seep in. This is reflected in the fact that total space heating costs in an airtight construction may
be as much as 40% less than in a leaky one.
Another issue associated with air leakage in buildings is that warm and often moist air can escape to colder parts of the outer construction where it can cool and condense, leading to a build-up of moisture. This in turn can lead to:-
Decay of organic materials such as timber frames. Saturation of insulating materials, thus reducing their insulative effect (further increasing heat loss). Corrosion of metal components. Frost damage where moisture has accumulated on the cold side of
Air leakage through cracks, holes or gaps causes a significant reduction in the thermal performance and efficiency of a structure. However this can be remedied by careful design and good quality construction practice.
The Solution - Wraptite and Wraptite Tape are effective methods of stopping unwanted air leakage. Wraptite is a self-adhering airtight membrane which consists of a triple layer polypropylene micro-porous film laminate with a proprietary moisture
vapour-permeable adhesive, plus a silicon-coated PET release liner. It can be used in full wall applications, on pitched roofs (under metal, tile, slate, wood shingles and clay tile) and for window flashings or other details.
Wraptite combines the best properties of a vapour-permeable membrane and an airtight membrane in one innovative, affordable self-adhering product. It fully bonds (no primer or mechanical attachments required) to almost any substrate for air tightness
and ease of installation, negating the requirement for sealants or tapes.
Penetrations in sheet material such as pipes, ducts and electrical work also need to be sealed to ensure compliance with air pressure testing. Wraptite Tape is an air tightness tape that has all the benefits of Wraptite, but with the convenience
of a tape. Air tight Wraptite Tape is tear resistant and offers high vapour permeability for internal and external applications. It is also suitable for permanent airtight sealing of membrane overlaps. Detailing is quick and easy, providing an effective,
convenient solution to what can be an expensive problem.
Wraptite: All-in-One - Wraptite products do not require a primer and can be installed in temperatures as low as 0°C.Its wide service temperature range means it can be easily installed in all climates. It is very easy to install, with a tough facer laminate
that resists rips, punctures and tears. Wraptite is fully bonded, hence fasteners are not required at installation; this prevents lateral air movement, further enhancing the building’s thermal performance, and increasing performance in an air leak
test. Being highly water vapour permeable, Wraptite thereby reduces potential for trapped interior moisture and condensation. Wraptite is resistant for up to six weeks of UV and climate exposure.
Wraptite and Wraptite Tape are unsurpassed in performance. Both offering an SD rating of 0.039, Wraptite and Wraptite tape provide a highly vapour-permeable, yet airtight performance for a wide variety of applications and conditions, and offer
an optimal solution for achieving excellent results in an air pressure test. They allow damp sheathing to dry quickly and moisture vapour to escape, ensuring good indoor air quality while reducing incidence of mould, mildew, condensation, timber distortion
and metal corrosion. The unique characteristics of Wraptite allow the moisture vapour to escape the structure easily, while fully maintaining the integrity of the air-tight building envelope.