You might’ve used house wrap sometime in the past to protect the outer sheathing of your walls or read about its protective attributes online and wondered if you could use it on a roof.
Well, the answer to this isn’t so straightforward. House wraps aren’t designed to be used as a surface finish for a roof, but they can sometimes be used as roofing underlayment.
Over the years, these wall coverings have evolved considerably, so much so that at present, it’d be insubstantial to refer to them simply as water-resistive barriers.
A lot of DIYers and contractors can’t seem to agree on whether or not house wrap is a suitable building material to use on a roof, and that’s where we come in to shed some light.
Is House Wrap the Same as Roof Felt?
Although house wrap and roofing felt are both weather-resistive barriers, their internal and physical make-up are not the same. Also, house wrap isn’t as difficult to install as roofing felt.
House wrap is a water-resistant synthetic board material, fabric, or paper that is commonly used to wrap the outer sheathing of a wall.
Roofing felt, on the other hand, is a sheet or mat that can be made of synthetic or natural materials. It is coated with bitumen or other protective materials to keep its surface impervious to water.
When it comes to durability, roofing felt lasts much longer than house wrap; this is because compared to house wrap, it is less susceptible to sunlight and moisture damage.
Roofing felt, otherwise known as tar paper, has a lot of seams; due to this, air sealing issues are pretty common when installing this material. It takes extra caution to install roofing felt successfully.
Contradictorily, the installation process for house wrap is quite easy. All you need to do is staple the wrap to the sheathing with a hammer tacker.
Another noteworthy difference between house wrap and roofing felt is that the first is water-resistant while the latter is water-proof.
Here’s a table that summarizes all the information provided above.
|House Wrap||Roofing Felt|
|Generally used on walls||To be used on roof|
|Not so durable||Very durable|
|Easy to install||Not easy to install|
|Not safe to walk on||Safe to walk on|
|Expensive||Not so expensive|
Do House Wraps Work on Roofs?
Despite the fact that house wrap is commonly used to protect wall cavities, these barriers can sometimes be used as roofing underlayment. Kindly note that it is not advisable to use house wrap as a surface finish for a roof.
This weather-resistive barrier has very few anti-slip properties; this is why it’s better off as a roofing underlayment than a surface finish.
Not all house wraps can be used as an underlayment; only those with a testing report showing it’s suitable for this function can be used.
For a successful installation, put as few holes in the house wrap as possible, or better yet, use a proper roofing underlayment.
What Underlayment to Use for Shingles?
The type of underlayment you use underneath roof shingles depends on the specifications of your local building code, the preference of your roofer, or the recommendations of the manufacturer of your roofing products.
Generally, asphalt-saturated felt matches well with traditional shingles, while roofing sheets that retain heat (e.g., metal roofing sheets) go perfectly with synthetic underlayment.
The climate of your region is also a major determinant of the type of underlayment you can use for your shingles.
For instance, if where you live is prone to snow and windstorms, a super thick or heavy asphalt-saturated felt would be most suitable for your roof.
In hot or very wet regions, homes or buildings require synthetic underlayment underneath roofing shingles.
Now that we’ve gotten this out of the way let’s take a closer look at the types of roofing underlayment on the market.
- Asphalt-Saturated Felt
This type of roofing underlayment has been around for ages. It is made of an organic mat or sheet coated in protective materials such as bitumen to make it resistant to water damage.
Asphalt-saturated felt can also be referred to as tar paper. You can get it either in a 15-pound per hundred square feet roll or 30-pound per hundred square feet roll.
The size or weight of tar paper you go with depends on the nature of your project. For instance, heavy-duty roofing projects require a 30-pound roll of tar paper.
Lightweight roofing projects like shed roof installations require a 15-pound roll of tar paper.
Most DIYers and roofers prefer to use a 30-pound asphalt-saturated felt for any roofing project, irrespective of its nature; this is because it’s much stronger than the other size of felt.
- Rubberized Asphalt Underlayment
Despite their staggering costs, rubberized asphalt felt remains one of the most popular roofing underlayments on the market. It is also known as self-adhered underlayment.
This type of underlayment contains high amounts of asphalt and rubber polymers and has a protective layer that shields its sticky side.
All you have to do to install this type of underlayment is peel off the protective layer and smoothen the sticky part of the felt over the roofing deck.
No fasteners are needed to install rubberized asphalt felt, but they can self-seal around nails and staples.
You can leave this type of underlayment on your roofing deck without shingles for as long as 180 days, they’re more durable than asphalt-saturated felt and are beyond efficient at protecting your roof from water damage.
- Synthetic Underlayment
With a synthetic makeup of polypropylene polymers or polyethylene, synthetic underlayment has an impeccably high tear strength and is quite resistant to water and wind damage.
This type of underlayment weighs a lot less than asphalt underlayment, and it’s resistant to UV rays. It also prevents mold and mildew buildup.
Synthetic underlayment is the most popular weather-resistive barrier used in the US today. It has way more coverage per roll and clear overlap guides that ensure you install them successfully.
In some cases, house wrap can serve as an equally functional alternative to roofing underlayment.
After all, newer versions of this building product encompass most of the features or qualities of roofing felt.
To be safe, use the underlayment recommended by the manufacturers of your roofing shingle so as not to violate the product warranty.
If you’re willing to forfeit the warranty, maybe because it isn’t worth much, make sure you carry out proper research or consult a professional before choosing a different roofing underlayment.
We hope you found this article super helpful, and we wish you the best of luck on your roofing project.