House Wrap Applications
If you are either having a new house built or an existing home re-sided,
you may want to know if home wrap is being applied onto your exterior sheathing,
beneath the siding. Tyvek and Typar are two very popular wraps although there are others.
There are some important reasons in favor of applying house wrap.
A major reason among remodelers is that it offers a degree of protection against
damage due to water infiltration. Without this barrier, moisture can
accumulate and trap inside the wall, entering into the framing. Over time, this
takes a toll on your outer carpentry and sheathing. The quality wrap will actually help lessen moisture
content within the wall itself - that is, one with an upward Moisture Vapor Transmission
Rate (MVTR) - emitting moisture from inside while and helping to keep it dry, this preserving exterior
trim and siding.
A main advantage of quality wraps on the market is that they are much easier
to install than the felt paper (asphalt tar paper). Anyone who has handled materials
such as Tyvek instantly notices its durability in appearance and tear resistance,
well beyond the heavier black sticky rolls. If it has a disadvantage, some of
the wider rolls are clumsy given their length. But unrolling these doesn't seem much an issue
since its easy to see that the more continuous rolls are intended to
form a barrier in a more seamless fashion.
Which brings up the next point, wraps can minimize airflow. While this may be done
especially on older remodel projects having a greater amount of exposure, or in windier
climates (coming from seams in underlayment/sheathing) benefits may also be in the
form of energy reduction for heating and cooling. Not to mention the reduction
in unwanted drafts. All of which assumes a proper installation of material.
Wrap materials also offer varying UV protection - the layer of material can remain
on the exterior surface for some period of time under the suns rays before the siding or what have you is installed.
Usually, the total costs for wrapping are low compared to benefits. However the higher
end wraps are considerably more than felt paper. Though remember, your home should ‘breath.’
In the larger picture, at the same time, beware of not to wrap a home too
snug and in-turn cause adverse affects. There are rare exceptions to the need
for house wrap and always consult the maker before applying.
The application of house wrap is not required by code in all communities. Some homeowners are surprised during a repair
of brick or siding to find out that this has not been done.