Friday, April 19, 2024
HomeFactsDo You Need Felt Paper Under Metal Roofing

Do You Need Felt Paper Under Metal Roofing

Ask A Question Or Search Inspectapedia

Metal Roofing Underlayment: Felt Paper, Synthetic, Peel & Stick

Try the search box just below, or if you prefer, post a question or comment in the box below and we will respond promptly.

Search the InspectApedia website

Note: appearance of your Comment below may be delayed:if your comment contains an image, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Barricade Udl Select: Quick And Easy To Install

Barricade® UDL Select installs much faster and easier than asphalt felt because it doesnt wrinkle and lies perfectly flat. Offering 33 percent more coverage per lap than 36-inch felt, and 14 percent more coverage than other 42-inch synthetics UDL Selects features save contractors time and money. UDL Select underlayment also has an anti-slip coating on both sides and weighs less than asphalt felt alternatives.

Barricade® UDL Select synthetic underlayment for metal roofs has superior heat and UV resistance, which helps protect the building or home. For the best underlayment for metal roofs, choose Barricade® UDL Select.

So Much Protection So Many Options

Metal roofing with effective underlayment provides so many advantages compared to other roofing types. Among them:

  • Metal roofing is lighter than other materials
  • Its energy-efficient, reflecting heat away from your home
  • It lasts longer because there is no chance for rotting or rusting even moss wont gain a foothold
  • Easy maintenance
  • Aluminum is versatile

Don’t Miss: How To Cool Seal A Mobile Home Roof

Install Drip Edge Flashing Below Underlayment Or Ice

Our photo above illustrates several details of roof drip edge, eaves flashing, and gable end flashing at an asphalt-shingle re-roof job we documented in Dutchess County, New York. From left to right:

  • Green arrow: points to the white aluminum drip edge installed at the lower roof edge. Drip edge is also sold in brown, black and some other colours.Drip edge flashing directs roof runoff away from the roof fascia and edge and into gutters or at least not down the fascia board and it is recommended by roofing standards, manufacturers, and experts.

See DRIP EDGE FLASHING for ROOFS for complete details about installing drip edge.

Inadequacy Of Roofing Felt As A Vapor Barrier For Asphalt Shingles In Hot Humid Climates

Underlayment for Metal Roof and the Material Types

A Building Sciences Corporation report lso elaborates the usefulness of placing a vapor barrier on the roof deck below shingles in hot humid climates. BSC points out that:

Unvented roofs with asphalt shingles in hot humid climates require a vaporbarrier between the asphalt shingles and the roof deck. This is because asphalt roofing materials store water from dew or rain.

Thus asphalt shingles form a water reservoir not unlike wood shingle or shake roofs.

The report argues that this stored moisture is driven inwards when sun strikes the damp or wet roof surface, and it continues to argue that moisture is driven through vapor-permeable roofing paper, felt, and plywood or OSB roof decking, thus ultimately into the attic space

But unlike an asphalt shingle roof nailed directly to a roof deck, a wood shingle or shake roof that has been installed using best practices includes a disposal path for water absorbed in the roof surface: an air space between the wood roofing and the roof deck, or the installation of wood roofing over spaced nailers or “skip sheathing”.

In cool or temperate climates this does not present a problem because the combination of heavy wetting from due or rain i snot combined with solar heating at high outdoor temperatures, say the authors who go on to argue that that buckled roof shingles observed in the morning relax during the day.

But on an un-vented roof moisture driven inwards in hot humid climates, needs to be addressed.


Don’t Miss: A Team Roofing Collierville Tn

How To Install Felt Paper

Extreme caution needs to be exercised when working on your shed roof and installing roofing felt paper. If not properly secured down to your shed roofing, accidents will occur while working on top of the felt paper. The following guidelines are general and you should always follow the manufacturers installation instructions located on the roll of felt paper you use.

  • Make sure your roof deck is clean and free of debris. If you are using drip edge you will want to install it on your eaves first, and the rake edges after the paper is put down.
  • Starting from the bottom of your roof, roll the paper out going from edge to edge, leaving 1/2″ overlap past the edges and trim.
  • Secure the paper in place with plastic capped roofing nails every 12″ with the exception of doing the top edge.
  • Overlap the next layer of paper on the previous , then secure this layer as you did the previous with your plastic capped roofing nails.
  • When you get up to the ridge of your shed roof, overlap the ridge with the paper

Would you prefer to share this page with others by linking to it?

  • Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment,your Facebook account, or anywhere that someone would find this page valuable.
  • What Is Drip Edge

    Drip Edge is a thin metal flashing that is applied to the edges of your roof underneath the shingles. The main purpose of the drip edge is to direct the flow of water away from the fascia board and to help protect the rakes and eaves of your roof.

    Drip Edge is commonly made of steel that is galvanized or covered in a protective coating like galvalume or a painted finish. You may also find it made from other materials like aluminum, copper, or vinyl.

    Worried About Doing the Work Yourself?

    I recommend finding a professional roofing contractor through our trusted partner Home Advisor because they allow you to get up to 4 quotes for free. This allows you to compare and choose the best roofing professional for your needs. Check them out by clicking this link.

    Recommended Reading: How Much Should It Cost To Replace A Roof

    Why Use Roofing Felt Paper

    Roofing experts have discovered that adding a layer of protection between your structural roof decking and your roof shingles helps create a better-looking and longer-lasting roof. In fact, there are a number of important ways roofing felt not only protects your roof, but also your residence. For example:

  • It repels waterWind-driven rain or snow can trap water under your shingles, putting your roof deck and inner residence at risk of moisture damage, leaks, rot and mold. Roofing felt helps ensure the water drains off the roof and doesnt leak into your home.
  • It provides backup protection in the event of ice or water damageIn northern climates, ice or snow dams are another common cause of residential water damage. When the heat from your home melts snow or ice on your roof, the water can then seep into your roofs nooks and crannies and ultimately into your residence, causing damage to ceilings, walls, or insulation. Your best protection against an ice dam is an ice and water protection membrane which can seal around the shanks of the roof fasteners for a leak-resistant fit. However, roofing felt offers additional protection against leakage, providing an extra layer of water resistance.
  • It protects your roof deck while you work on itRoofing felt prevents the deck from being exposed to the elements before, or while, the shingles are being applied.
  • Which Weight Is Right For Your Project

    Roofing – Installing Tarpaper Felt – The Basics – Dry in of Mockup

    For many years, roofers used asphalt saturated felt under roofing shingles, and it was historically available in two standard weights: 15 pounds per hundred square feet and 30 pounds per hundred square feet. The 15 pound was for lighter weight projects, while the 30 offered more heavy duty protection. Today, the actual weights have changed, but the categories have stuck.

    The information on this website is subject to change without notice. IKO assumes no responsibility for errors that may appear on this website.

    IKO strives to accurately reproduce the screen images of the shingle swatches and house photos shown. However, due to manufacturing variances, the limitations of your monitor resolution and the variation in natural exterior lighting, actual colors may vary from the images you see. To ensure complete satisfaction you should make final color selections from several full size shingles and view a sample of the product installed on a home. Please refer to our Legal Notices for U.S.A. or our Legal Notices for Canada.

    Don’t Miss: How Many Roof Vents Do I Need

    What Do You Put Under Siding

    The wood that goes under residential siding exterior sheathing performs several functions. It adds insulation, waterproofing and structural support for the framing. It also provides a surface on which to nail the siding. The most common sheathing materials include oriented strand board and plywood.

    There Are Stages To A Roofing Project

    The modern roof has multiple layers. On top of the rafters or joists there is sheathing. Generally made from half inch OSB or plywood, this is what provides the bulk of the support for anything that hits, lands, or walks on top of your roof. That sheathing is covered with an underlayment that is designed to be waterproof, helping to stop any moisture that makes it past the shingles or metal. Over the underlayment the shingles or metal is applied.

    There are some roofers out there that believe that since metal is such a great material, and since it generally comes in large sheets making it all but impermeable, they can skip the underlayment section and attach the metal directly to the sheathing. Their attempt to save money may cost them more in the long run.

    You May Like: How To Insulate Pole Barn Roof

    Does Felt Paper Go Over Ice And Water Shield

    Ice and water shieldfelt paperbarrierwaterFelt paper does

    . Similarly, do you need felt over ice and water shield?

    Drip Edge, Ice& Water shield and roofing paper. It is not absolutely necessary but it is extra protection over that area of the roof that could potentially have water backing up from roof edge ice dams, up and under the shingles. Many building codes now require this layer.

    Additionally, can ice and water shield be installed over tar paper? But if you call them, they will tell you a single layer of ice and water shield is acceptable, no underlayment required over it.

    Also know, does underlayment go over ice and water shield?

    5 Drip Edge says, Underlayment shall be installed over the drip edge along eaves . Because the icebarrier membrane in this situation is taking the place of the underlayment along the eaves edge, it should be installed over the drip edge according to the code.

    How far up should ice and water shield go?

    The minimum is typically 2 feet above the vertical projection of the inside of the exterior wall. In colder regions, a good practice is to cover the first 3 feet of roof over heated space with ice and water protector. All overhangs should also be covered.

    Underlayment On Standard Slopes Where Asphalt Roof Shingles Are Installed

    Roofing Underlayment â Roof Online

    As stated in Best Practices Guide to Residential Construction:

    On roofs with a slope of 4:12 orgreater, use a single layer of 15 lb. asphalt-saturated felt,starting at the eaves and lapping upper courses over lowerby a minimum of 2 inches. Vertical joints should lap a minimumof 4 inches and be offset by at least 6 feet in successiverows .

    Secure each shingle course along seams and edges withenough corrosion-resistant nails to hold it in place untilthe roofing is installed.

    In high-wind areas, apply fastenersa maximum of 36 inches on-center along overlaps.

    Don’t Miss: How To Replace Asphalt Roof

    Does Drip Edge Go Over Or Under Felt Paper

    While doing any roof work, its important that everything is layered so water drains off properly. The placement of the drip edge is critical to help prevent rotting due to water damage. Where do you install drip edge in relation to the underfelt paper?

    If the drip edge is along the eaves of the roof, it goes underneath the felt underlayment. When the drip edge is along the rake edges, it is placed over the felt paper underlayment.

    If you are not a professional, do not fret, as it isnt too hard to grasp. Discover what the purpose of drip edge and felt paper is and why you place the drip edge over or under felt paper. Ill also explain the differences between eaves and rake edges.

    Why Does Drip Edge Go Underneath the Felt Paper on the Eaves of the Roof?

    When you install the drip edge under the felt paper along the eaves of the roof, this will allow water to flow freely over the drip edge. Whenever you are dealing with a roof, it is imperative that you always keep in mind the direction or path water will run along and off the roof.

    If the drip edge was installed over the felt paper or and underlayment, water may puddle up against the drip edge. Over time some water may work its way under the drip edge and get onto the wood underneath. This will cause your roof to start rotting, so be sure to place the drip edge underneath the felt paper on the eaves of the roof.

    Why Does Drip Edge Go Over The Felt Paper On The Rake Edges Of The Roof?

    What Is The Purpose Of Drip Edge?

    The Best Underlayment For Metal Roofs

    The first goal of roofing underlayment is to keep the roof deck dry before installation of the metal roofing material. Underlayment must also act as a secondary weather barrier in case the roof fails. Traditionally, metal roofs have used standard 30-pound felt paper underlayment. However, contractors now recognize the benefits of synthetic underlayment for metal roofing, particularly when it comes to its tolerance to heat and ultraviolet radiation.

    Don’t Miss: How To Change A Flat Roof

    Why Should You Use Felt Paper On Your Shed Roof

    There are a number of reasons for the installation of felt paper on your shed roof.

    • It repels water.
    • In the event of ice and water damage it will provide back up protection.
    • It provides extra protection against the weather.
    • It may be required by your building code in your local municipality.
    • It will protect your roof decking while working on your roof.
    • It will help your shed roof look better. It will provide a more uniform look and prevent that picture frame effect from the edges of the roof panels.
    • Felt paper prevents stains from wood resins.

    Roofing Felt Installation Details

    Underlayment and Metal Roofing â Metal Roofing 101 with Todd Miller

    Reader questions on roofing felt installation specifics

    Anonymous said:

    Hi Dan, a couple of roofing questions:

    1) We often see roof felt stopped short of the eaves. Builders argue its not a problem. I once had a written opinion from NRCA stating felt needed all the way to the eaves but can’t find it anymore. Any known reference clearly indicating need to felt to eaves?

    2) Asphalt shingles on less than 2:12 pitch, builder says ice& water shield under it, I know that’s not OK but again any reference source you may know of?Hope all is well in NY land, nice here in Raleighwood. – Steve Smallman


    Thanks for the important questions Steve:

    1. Felt underlayment omission from some roof areas: this defect – taking a shortcut by leaving off some roofing felt, is an example of a wider problem: building codes & standards writers have given up on trying to anticipate every possible way that people can make a mistake, shifting instead often to “performance” codes that give the general intent of the code. So we’ll have trouble finding an explicit citation for your question part 1.

    But a reading of roof shingle manufacturer’s specifications for using an underlayment does not find any exceptions that allow leaving out some of the coverage area.

    I’d excuse the omission of felt at the eaves and at rake edges of a roof IF instead the roofer is installing a stick-down impermeable barrier such as ice and water shield. Otherwise it’s a mistake.


    Also Check: How To Fix Gazebo Roof

    Do You Need A Vapor Barrier Under A Metal Roof

    Vapor barriers are used to reduce the amount of condensation that can move through a material. When theyre installed properly, they can help reduce any problems that you have with condensation as well as air leakage on fiberglass-insulated walls. Without one, water can get trapped in the wall, which will produce moisture and ultimately other issues like rot, mold, and trouble with thermal performance. Vapor barriers are recommended for under metal roofs.

    Felt Paper Underlayment Disadvantages

    DOESNT LAST AS LONG The biggest issue with felt paper underlayment is that it doesnt last as long as a synthetic underlayment. Longevity varies dramatically from manufacturer to manufacturer since this material is most popular with shingle roofing, most felt paper is warranted for the lifetime of a shingle roof . Felt underlayment will break down and weaken over time, especially if exposed to high heat, sun exposure, or frequent temperate fluctuations.

    HIGH-TEMPERATURE PROBLEMS Another problem that could arise with felt underlayment is that it doesnt respond well in high heat environments. Asphalt is a semi-solid form of petroleum and an oil-based product, so it is more susceptible to high temperatures breaking down the material, drying out the oil, cracking, and ultimately degrading prematurely.

    LESS EXPOSURE TIME Felt underlayment should not be exposed to sunlight for an extended period of time. How long it can be is dependent on how much asphalt/oil is in it and how quickly the material will dry out and not perform properly. According to Construction Pro Tips, some roofing felt can bubble, buckle, and wrinkle within just 24 hours of UV exposure. These imperfections created in the felt can even translate through shingles or metal panels to create an unsightly surface.

    Read Also: How To Seal Your Roof


    Most Popular