Choosing whether or not to install a house wrap doesn’t seem like it should be a difficult decision to make, and yet both homeowners and home builders alike have varying opinions on the matter. Some believe it’s absolutely required, while others think that it’s an unnecessary additional cost.
So as the owner of a new or otherwise newly-remodeled home, then, whose advice should you follow?
In this article, we’ll clear the air about what house wraps can and can’t do so you can make a properly informed decision for your home.
What is a House Wrap?
To better understand what a house wrap is and how it works, let’s first break down the science of home weatherproofing. Generally speaking, weatherproofing involves designing and building the external walls of a building to protect the interior from undesirable elements such as wind, water, moisture, and temperature. The most effective method that we use today is to use a series of materials layered in such a way that protects both the house and the materials themselves from the components of weather damage.
The most commonly-used materials in weatherproofing are foam insulation to regulate the home’s temperature, a plastic or foil vapor barrier to control moisture, and brick, wood, vinyl, or other materials for the external siding, which handles the brunt of the wind and water.
Sandwiched between the house’s sheathing and the external siding, the house wrap serves as an additional line of defense against inclement weather.
Traditionally, house wraps were done with a material called tar paper, but further advancements in material science have produced synthetic materials like Typar and Tyvek, which are now the standard for house wrapping materials.
Regardless of what material is used, all of these house wraps are known as semi-permeable materials, which means they are designed to block out large water droplets like rain while allowing smaller particles like water vapor to pass through to the outside.
Do you Actually Need House Wrap?
So, to set the record straight: no, it is not necessary to install a house wrap in most homes.
From a legal standpoint, many local building codes don’t actually require homes to have a house wrap installed. In such cases, only an internal vapor barrier is needed to comply with these codes, making the house wrap an optional addition.
Of course, you should always check with the codes or your local authorities to know exactly what is needed for compliance.
Even if you aren’t required to install a house wrap, though, we would still suggest having it installed anyway, as the benefits it offers for your home could make it a worthwhile investment.
Benefits of House Wrap
Although your vinyl siding is responsible for keeping rainwater from reaching the wood sheathing and other components underneath, it can only do so much. Even if the builders manage to install your siding with perfect seals and absolutely no gaps, there is no telling whether those seals will still perform the same way in 5 or 10 years.
And we haven’t yet considered the fact that the siding panels themselves could have cracks and other imperfections that would let wind and water through. The house wrap’s role as an additional line of defense is essential for the most assurance against weather damage.
Regardless of the climate a house is in, insulation is practically a necessity for most modern houses, helping to reduce the house’s thermal leakage (i.e. internal heat escaping the home in the winter and outside heat entering the home in the summer).
However, most insulating materials lose much of their effectiveness when exposed to the elements. Water is especially notorious for causing damage to insulating materials through soaking and providing the right conditions for mold growth.
A good house wrap will improve the house’s insulation by sealing off all of the little leaks and gaps in the walls that tend to arise during construction and are generally unavoidable. With no gaps left in the house’s structure, its interior temperature is maintained for longer, which in turn makes the house more energy-efficient as homeowners have less of a need to use heating or cooling.
Mold and mildew are some of the biggest maintenance challenges for homes in the more humid parts of the world. From the unsightly stains it leaves on walls to the unmistakable “old house” smell that permeates the inside air, mold growth from excessive moisture buildup in the house should be avoided at all costs.
Now, you might meet some homeowners or builders who believe that the house wrap could cause mold and mildew buildup in the walls because the material could trap moisture. Not only is this completely false, but the house wrap actually has the opposite effect.
While it won’t be able to rectify a home’s mold problem if it already has one, installing a house wrap is very effective at preventing the same from happening to a new home. The house wrap’s semi-permeable property allows the walls to “breathe out” any moisture buildup in the walls, keeping the internal structures dry and mold-free.
What’s the catch?
From what we’ve discussed so far, house wraps don’t really have any inherent drawbacks to speak of. However, we touched on earlier that the effectiveness of the house wrap largely depends on how well the wrap was installed.
A house wrap that isn’t mounted correctly or doesn’t cover the entirety of the house would introduce ingress points for rain that would not be able to drain out of the wall, which produces the opposite effect of what the house wrap was made to do.
Although the process for installing house wrap is not necessarily difficult, there is still the ever-present potential for a worker misstep during the installation. As such, homeowners must be aware of the quality of the work being done on their houses to ensure they will last through the generations.
