Housewrap
A sarking membrane is a flat component that is arranged in sloping roofs below a water-diverting roof covering. It is used to derive drifting snow or rain that is blown by the wind under the buy down. In contrast to the underlay sheet, which rests on a dimensionally stable base, it is tensioned freely between the rafters. An undervoltage must be ventilated on both sides ( primary ventilation level).
Diffusion openness initially no role to play in lower voltages (typically Sd value: 3 m).
One insulation between the rafters must hold when it is not open to diffusion, to ensure removal of internally migrating to the outside humidity by air flow beneath the path from the eaves to the ridge through at least 2 cm from the underlayment.
However, if a layer of insulation to installed close to the web ( eg a subsequently blown cellulose insulation ), one speaks of a shortfall, the web must be open to diffusion in this case (typical Sd value: 0,02 m).
Vapour-permeable underlay and undercover sheets there are many. They differ in the layer structure, in the material, in the nature of the functional membrane, and in weight. As a result, the cars are only apparently similar. Four tracks types, it is important to distinguish:
- Fleece combined with a microporous membrane function
- Fleeces combined with monolithic functional membrane
- Products made entirely of spunbond
- Fleece combined with coating
Today, classic underlays are usually only used in undeveloped attics.
The path should sag slightly in order to remove the accumulated water from the counter battens away and down. The webs should each overlap the underlying web 10 to 20 cm. The joints and seams can be glued by the undervoltage is the closed deck pad for securing against wind forces. Upon execution, the relevant product and manufacturer's instructions should be considered.
After the product data sheet for underlays ( USB) of the Central Association of German Roofers ( ZVDH ) should be developed for residential purposes in and insulated roof spaces are provided Behelfsdeckungen. An underlayment applies as a provisional when all connections secured against running behind and nail sealing tapes are used under the counter battens.
Linings of all kinds, which are used in the traditional pitched roof are also called roofing sheets.
A special form are lining membranes. These are generally underlays, which (usually a continuous layer of boards ) are intended for installation on a formwork level.
Facade membranes are used on vertical surfaces.