Housewrap

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A building wrapped with Tyvek-brand housewrap during construction Tyvek house wrap.jpg
A building wrapped with Tyvek-brand housewrap during construction

Housewrap (or house wrap), also known by the genericized trademark homewrap (or home wrap), generally denotes a modern synthetic material used to protect buildings. Housewrap functions as a weather-resistant barrier, preventing rain or other forms of moisture from getting into the wall assembly while allowing water vapor to pass to the exterior. If moisture from either direction is allowed to build up within stud or cavity walls, mold and rot can set in and fiberglass or cellulose insulation will lose its R-value due to heat-conducting moisture. House wrap may also serve as an air barrier if it is sealed carefully at seams. [1]

Contents

Housewrap is a replacement for the older tar paper or asphalt saturated felt on walls. It is lighter in weight, available in much wider rolls, and both faster and easier to apply.

Major types

Installation

Housewrap is installed between the sheathing and the exterior siding, and is utilized behind vinyl, wood clapboards, shingles or shakes, brick, and other building materials. In all cases, the housewrap helps prevent water intrusion when moisture in any form gets past the siding and its trim and caulking.

As such, housewrap must be both water shedding and have a high moisture vapor transmission rate (MVTR) to be effective. [2] It must also withstand abuse during installation, hold up in significant winds while awaiting exterior siding installation, and, as housewrap is often left exposed for some time before being cladded-over, be resistant to UV. Some new designs must be installed carefully or they will slightly rip or tear during installation, possibly allowing for water infiltration at the damaged areas. Being both thin and inelastic, most newer designs do not "self-seal" well against nails or staples like asphalt products.

Properties

Related Research Articles

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<span class="mw-page-title-main">Exterior insulation finishing system</span> Non-load bearing building cladding

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<span class="mw-page-title-main">Vapor barrier</span> Damp proofing material in sheet form

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<span class="mw-page-title-main">Damp proofing</span> Type of moisture control in building construction

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<span class="mw-page-title-main">Cement board</span> Backing board used in building construction

A cement board is a combination of cement and reinforcing fibers formed into sheets, of varying thickness that are typically used as a tile backing board. Cement board can be nailed or screwed to wood or steel studs to create a substrate for vertical tile and attached horizontally to plywood for tile floors, kitchen counters and backsplashes. It can be used on the exterior of buildings as a base for exterior plaster (stucco) systems and sometimes as the finish system itself.

<span class="mw-page-title-main">Building insulation material</span>

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<span class="mw-page-title-main">Rainscreen</span>

A rainscreen is an exterior wall detail where the siding stands off from the moisture-resistant surface of an air/water barrier applied to the sheathing to create a capillary break and to allow drainage and evaporation. The rainscreen is the cladding or siding itself but the term rainscreen implies a system of building. Ideally the rainscreen prevents the wall air/water barrier from getting wet but because of cladding attachments and penetrations water is likely to reach this point, and hence materials are selected to be moisture tolerant and integrated with flashing. In some cases a rainscreen wall is called a pressure-equalized rainscreen wall where the ventilation openings are large enough for the air pressure to nearly equalize on both sides of the rain screen, but this name has been criticized as being redundant and is only useful to scientists and engineers.

Interstitial condensation is a type of condensation that may occur within an enclosed wall, roof or floor cavity structure, which can create dampening.

References

  1. Krigger, John; Chris Dorsi (2004). Residential Energy: Cost Savings and Comfort for Existing Buildings. Helena, Montana: Saturn Resource Management. p.  110. ISBN   1-880120-12-7. OCLC   56315804.
  2. Reed, Ryan (May 2004). "Housewrap Felt or Paper: Comparing specs on weather barriers". BUILDERnews Magazine. Pacific NW Publishing, Inc. Archived from the original on 2004-08-20. Retrieved 2016-02-24.