Why House Wrap?

Builders!

When you go out in bad weather, you put on a raincoat or windbreaker, and you shouldn’t build a new house without giving it protection against air and moisture infiltration either.

Just shy of a decade in the mainstream market, house wrap and other weatherization products are now becoming well known among builders and contractors.

A proven, dependable product category that essentially sells itself would appear to present few challenges beyond keeping adequate inventory.  But, as dealers continue to dedicate resources to expanding their knowledge and offerings in dimensional lumber and other commodity categories, maintaining strong market share for a price-competitive product such as house wrap can pose a challenge that calls for focused attention on innovative sales and marketing approaches.

Why use house wrap?

Various weather-resistive barriers, placed over exterior sheathing, have been used in home construction for decades.  "Building paper", traditionally a sheet of paper or felt with an asphalt coating, was designed primarily to protect the house from exterior water penetration, and is still widely used today - but developments in materials in recent times have led to the introduction of extremely versatile synthetic "house wrap" materials.  These materials not only protect the home from exterior water penetration, but also resist air infiltration while still allowing moisture from inside the house to escape.

At an average cost of about 25 cents per square foot, house wrap should pay for itself in energy savings in just a few years.

To help maintain loyalty among their pro customers, and get some additional drive-by PR at the same time, many distributors take advantage of their manufacturers' offer to print their name and logo on the house wrap itself.  Once unrolled on the exterior walls, the house wrap serves as a billboard of sorts, attracting the attention of passersby and various crews and contractors working in the area.

Most house wrap manufacturers have a minimum order size to print a logo on the product (about 180 rolls), as well as a onetime setup fee and additional lead time for delivery, and not all pro customers garner enough volume to justify the added cost.  Larger distributors, however, maintain enough house wrap inventory to offset the premium. 

Your logo on a roll of house wrap, as well as its appearance on a framed wall before the siding goes on, only scratches the surface of the value a dealer can add to a product category that is quickly earning commodity status.

Different brands also vary in their construction. A non-woven product, for instance, resembles paper in its installation and applied appearance, while a woven house wrap product's fabric-like construction appears smooth on the wall and is more tear resistant.

Dealers are learning the nuances of house wrap's impact on a home's energy efficiency, especially when integrated with other value-added products, such as insulated windows and upgraded insulation, along with the use of other tight-house construction techniques.  Energy savings, insulating value, and saving money on heating and cooling bills are all selling points to builders.

Part of understanding the value of house wrap is knowing the difference between it and a vapor barrier or rigid foam panel, as well as building paper or felt.  You also have to understand variations among house wrap products, such as perforated, non-perforated, woven, and nonwoven.

Knowing these and other differences in house wrap products helps dealers sell a package of integrated energy-efficient products that can help their contractor customers avoid latent problems such as moisture damage and related construction defects - creating a more consultative selling atmosphere when working with builders.

Educating builders and their crews to properly install house wrap requires a basic knowledge of how air and moisture pass through the exterior envelope, and the impact that various products have on that movement.

Everywhere two building materials come together, at every joint in exterior sheathing, you're likely to have a leak.  In fact, the average 2000 square foot home has about a half-mile of cracks and gaps.  This uses excess energy, leads to higher utility bills, and can lead to rotting and the development of fungus or mold.

house wrap serves as an air barrier, a vapor retarder, and a watershed that is installed between the exterior sheathing (often OSB) and the finished siding.  

house wrap that is properly installed 

Research indicates that house wrap reduces leakage of outside air through the wall assembly from 40 to 93%, and that a draft as light as ten miles an hour can decrease the effective “R” value of insulation by 63% in an unwrapped house.  In an unwrapped house, significant inside/outside air pressure differentials can be created that can either suck the AC or heated air out of the house or pull hot or cold air into the house from outdoors. Either way, you’re losing money.  The U.S. Department of Energy estimates that nationwide, $20 billion a year in energy dollars could be saved if all structures were built with optimal ventilation.

A house wrap's ability to block air infiltration or air transfer lessens the burden on the mechanical systems. The result is an HVAC system that performs better.  It doesn't operate as often or work as hard to condition the indoor air, and requires less maintenance over time - thus reducing energy costs.

Compared to 15-pound building felt or rigid foam, even un-taped house wrap is more effective at blocking the majority of air infiltration through the framed walls and it's easier and faster to install.

But...

To effectively inhibit air transfer through the wall, house wrap must:

Only a comprehensive approach to installation will optimize house wrap performance.  Taping joints, as opposed to simply overlapping the material, is an essential element to an airtight application. 

To insure they get the most value out of a house wrap, some dealers are adding the category to their list of installed products or factory-built components.  

As remodelers build room additions or replace siding, older homes also serve as an increasing market for house wrap - for many of the same reasons.  It's just much easier to put up compared to rigid foam or other alternatives.  When energy issues get hot, it's even easier to sell."

Prime Wrap® house wrap from CS Fabric

There is often a gap of several weeks between installing house wrap and installing the exterior finished siding, so it can be very important to use a house wrap that is tear-proof and highly resistant to ultra-violet light.

Prime Wrap® house wrap is a cross-woven polyethylene fabric with a durable plastic coating that makes it virtually tear-proof.