Nonwoven fabrics for building materials, manufactured to order

Construction is an unforgiving application for a fabric. The material goes up once, is covered by cladding or roofing, and then has to perform for the life of the building with no opportunity for inspection or replacement. That is why SMS composites have taken over house wrap and roofing underlay from the films and papers that preceded them: the spunbond faces give tear strength and nail-tear resistance for installation, and the meltblown core provides the barrier function, in one fabric that is dimensionally stable on the roll and on the wall.

Moisture management is the reason the fabric is there. An SMS house wrap is strongly water repellent, so bulk water driven against the building envelope does not collect in the wall cavity or seep into the structure, which is what causes mould growth and structural decay. At the same time the fabric is breathable, so water vapour generated inside the building escapes outward instead of condensing in the insulation. Getting both properties from one layer is the whole point of the construction, and it is set by the meltblown basis weight and the bonding pattern rather than by a coating.

Temperature serviceability is the second requirement. A membrane is installed in whatever weather the schedule delivers and then lives through the full annual cycle of the site, so it has to stay flexible when it is cold and dimensionally stable when a roof deck is in full sun. Polypropylene and polyester constructions hold their properties across that range, and their thermal stability contributes to the performance of the insulation behind them, which shows up as lower heating and cooling loads over the building's life.

Durability comes from treatment. UV stabilisers are specified according to how long the membrane is expected to stay exposed before cladding or roofing goes on, which on a real site is often much longer than the programme assumed. A stabilised fabric keeps its tensile strength and its barrier properties through that exposure instead of chalking and tearing at the fasteners. Flame-retardant grades are produced where the assembly or the local code requires them, and coloured grades are available where the membrane is visible or where a contractor needs to identify a grade at a glance. Coloured and treated grades, UV and FR, are available in widths up to 63 inches.

The same fabric family extends past the envelope. Roofing underlays use heavier constructions with the tear strength to survive foot traffic during installation. Wall insulation facings use lighter grades to contain fibre and give the batt a handling surface. Wall coverings use coated and laminated constructions where the finished face has to be printable, cleanable or dimensionally stable over a large area. Lamination and extrusion coating are applied to order where a fully waterproof layer or a specific vapour permeability is called for.

We manufacture construction nonwovens to order. Send the construction, basis weight, roll width and length, colour, UV and flame-retardant requirements and the quantity, and we will quote the specification delivered. The minimum order is one 40-foot container.