Typar® Laminated Housewrap

Typar Laminated Housewrap - Beware!


Laminated house wraps rely on a thin, fragile ­film layer to keep air and water out. But the functional layer can easily scratch and tear during the installation process, allowing water in the walls which can lead to exterior wall damage. DuPont Tyvek® weather barriers are made with a unique material that provides superior performance for keeping air and rain out while letting moisture escape. So don’t settle for less. Whether you’re building a new home, or residing or remodeling an existing one, insist on Tyvek® for superior weather protection. It’s no fairy tale.

TYPAR® house wrap and similar laminated-film products are comprised of a thin film coating on a polypropylene fiber mesh. The polypropylene backing consists of a coarse mesh, similar to that of a landscape fabric. This backing is needed to provide support for the thin film layer. This mesh is tear resistant but offers no protection for water and air penetration. The thin film coating, or functional layer, is added so minimum water and air resistance standards are met.

Tyvek versus TYPAR functional layer magnification

Also, as you can see in the electron micrograph image of TYPAR ® (right), the thickness of the functional layer is not consistent. In this particular example, the thickness varied from 4.8 to 22.6 microns – which is less than half the thickness of a human hair. The thinnest areas tend to occur above the protruding fibers, making these areas even more susceptible to damage.  By comparison, the entire thickness of Tyvek® HomeWrap® (left) functions as an air barrier and provides water resistance and is 4 to 20 times the thickness of the functional layer of TYPAR® depending on the point at which the functional layer of TYPAR® is measured.

Abrasion testing, conducted at the request of DuPont, was used to simulate real world exposure of both Tyvek® and TYPAR® to the rigors of a typical construction site. Next, Tyvek® and TYPAR® were tested for air and water resistance. Sample abrasion was conducted per ASTM D3884 on commercially available Tyvek® HomeWrap® and TYPAR® house wrap.

The following images that were taken with an electron microscope show samples Tyvek® HomeWrap® and TYPAR® after only 1 cycle of abrasion which is what you might expect to see after dragging a tool belt across the surface or fitting wood siding into place. 

Further examination using electron microscopy shows that although small fibers are pulled from the surface of Tyvek® HomeWrap®, the material underneath remains intact. The TYPAR® house wrap sample developed holes in the fragile functional layer which compromises the product’s ability to hold out air and water.


TYPAR® lost most of its effective water resistance after only After 1 abrasion cycle. The water resistance of Tyvek® was not significantly affected after 5 cycles.

Can minimal surface damage and a few microscopic holes really affect a product’s performance? To find out, both products were tested for air and water resistance after abrasion exposure.

All testing was performed using commercially available Tyvek® HomeWrap® and TYPAR® house wrap. The results are clear. TYPAR® house wrap lost virtually all of its measurable water resistance after only 1 abrasion cycle. If a WRB cannot effectively hold out water, it will not be able to hold out air. Therefore, minimal abrasion to TYPAR® would result in loss of air barrier properties.

Tyvek® HomeWrap® offers high vapor permeability without sacrificing resistance to air and bulk water penetration. Also, the functionality of the entire thickness ensures the product will perform after exposure to the rigors of the jobsite and installation. TYPAR®, on the other hand, relies on a thin functional layer which is susceptible to damage that can limit the products performance as an effective WRB. Once again, Tyvek® HomeWrap® offers the best balance of properties to help you build more durable, energy efficient structures.



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DuPont™ Tyvek® Certified Installers are on-site DuPont air-and-water barrier product experts, able to provide installation services that can help seal the building envelope.

TYPAR® is a registered trademark of Avintiv, Inc., a Berry Plastics Company.