The best subfloors for roofing in 2023 (2023)

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From the ground, onehereit looks like a simple set of inclined planes designed to expel water. However, roofs are actually complex systems of tiles, plywood, different types of flashing, membranes, vents,sealant, and more. Underneath it all is one of the most important components of the system: the cover.

The covering undercoat serves many purposes. Protects plywood decking from the weather, helping to wick away moisture and prevent leaks by maintaining a barrier between the roofing material and the decking. This guide will explain how to choose and what to look for in the best covering blankets.

  1. BEST OVERALL:Synthetic Roofing Felt Gaf FeltBuster
  2. BEST EARNING PER DOLLAR:Ceiling subfloor Grip-Rite ShingleLayment-15 GRE
  3. UPDATE SELECTION:GCP Grace Ice and Water Shield HT
  4. BEST SENSE:Warrior Roofing 30W Felt Roofs
  5. BEST RUBBER:GCP Grace Shield of Ice and Water
  6. BEST SYNTHETIC:Owens Corning ProArmor Synthetic Ceiling Subfloor
  7. ALSO CONSIDER:Ice and Water Infiltration Barrier Gaf WeatherWatch


Types of Roof Underlays

There are essentially three types of underlays for roofing: felt, rubberized and synthetic. Each has its pros and cons, and there are certain situations where one can stand out from the rest.


The felt cover layer, also known as felt paper, is the old version of the cover layer. These thick, heavy felt rolls include combinations of polyester and natural plant fibers soaked in bitumen (commonly known as asphalt). They are generally inexpensive compared to other materials and come in lighter (15 pounds) or heavier (30 pounds) varieties.

Although felt is more affordable, it's important to understand its drawbacks. First, it is very heavy and difficult to lift over a roof, so it comes in much shorter rolls than other materials. Also, felt paper is not very tear resistant; therefore, tiles must be installed immediately to prevent damage from the elements.


Rubber roofing underlayment is a different animal. These products are essentially rubber membranes that roofers can apply directly to the roof. One side of the membrane is smooth, while the other has a sticky substance known as butyl.

The rubber roofing membrane is highly adhesive and creates a waterproof barrier over the roof deck. It's the best material to prevent leaks from ice dams and other weather events, and many installers use rubberized underlays in conjunction with felt or synthetics.


The popularity of synthetic foundation is growing rapidly. These lightweight sheets made from woven or spunbonded synthetic fibers (polyethylene or polypropylene) provide a durable, weather-resistant barrier that is easy to apply and often includes tile or nail patterns printed on their faces.

Because synthetic undercoats are so light, manufacturers can offer more square feet per roll. They are more expensive, but the faster coverage that synthetic underlays offer due to their size can be a huge production boost. Also, because the fibers that make up synthetic linings are so durable, you don't have to cover them up as quickly as you do with felt.

What to consider when choosing the best roof undercoat

Before deciding on materials for a roofing project, there are a few considerations to make. The following sections include some of the most important points to consider when choosing the bestroofsubfloor

roof type

The type of roof can play an important role in choosing the best roof. Certain materials, such as asphalt shingles, metal roofing or slate, may require a specific type of underlay over another.

While it is always best to consult the manufacturer's instructions before deciding on an underlayment, the following guidelines may be helpful:

  • Asphalt Shingles – Almost all types of underlay are suitable for asphalt shingles.
  • Metal roofing: The expansion and contraction of metal roofing panels can wear down the felt or synthetic base. Rubberized subfloors are best for these ceilings.
  • Slate and Tile Roofing: For these classic or traditional roofing materials, many manufacturers recommend heavy duty #30 (30 lb.) felt paper as the base material.


The climate in which a home was built can determine which subfloor material to choose. For example, in colder climates where snow and ice predominate, the rubberized base is the most effective in preventing leaks. Rubberized underlayment is also better for extremely high temperatures. Synthetic blanket is generally better than felt because it allows moisture to escape and prevents water penetration, but both will work well in temperate climates.

Keep in mind that fire resistance is also important, especially for those in drier climates prone to wildfires. For the best protection, look for Class A certified underlays to combine with fire resistant shingles or other roofing materials.


The installation process between the three types of subfloors varies slightly and can be a determining factor for some DIYers.

Felt paper is very heavy, so manufacturers often sell it in rolls that are 3 feet wide (1 foot less than most synthetic liners). That means less coverage per roller and more trips up and down a ladder. After the felt paper is unrolled, users staple it to the deck surface. They should also be careful as the felt can tear and create a fall hazard.

Synthetic roofing underlay is much easier to install than felt. It's lighter and comes in wider rolls, which means more coverage with less work. However, it typically requires cap nails for installation, which are more expensive and require more effort to apply than staples. And while the original synthetic underlayments were slippery, today's versions are a bit tacky, providing a better foundation.

Rubber roofing underlay can be difficult to install. These rollers are heavy and don't offer a lot of coverage. The user must spread the material on the roof surface, cut it, and then remove the sticker paper before sticking it on the deck surface. Sticky butyl usually sticks to itself and becomes very difficult to separate. However, once cut and pasted on the ceiling, the user only needs to smooth the surface, without the need for nails or staples.

Tip: Apply a rubber base coat at lower temperatures (about 40 degrees Fahrenheit) to make the job as easy as possible.

Our best picks

That's a lot of knowledge about the best undercoats for roofing, but choosing just one product can still feel overwhelming. To help, check out some of the following top products on the market.

better overall

The best subfloors for roofing in 2023 (3)


People looking for a versatile coverage foundation should consider Gaf's FeltBuster Synthetic Coverage Foundation. Despite its name, this product is fully synthetic, designed to be tough enough to withstand the elements and light enough to carry it up and down a ladder with ease.

This synthetic cover comes in rolls that measure 250 feet long by 4 feet wide, allowing for coverage of up to 1,000 square feet. There is a convenient nail pattern on the face for accurate nail placement, and the material offers more traction than asphalt base for safer working conditions. The polypropylene material is class A fire resistant and lays flat in overlapping sections, promoting a more uniform and consistent appearance when the roof is finished. It's a little pricey, but it might be worth the investment.

product specifications

  • Type:Synthetic
  • Size:250 meters long by 4 meters wide
  • Fire resistance:a class


  • Lightweight, durable polypropylene construction.
  • Provides traction for security.
  • Nail pattern on the front
  • Class A fire resistant


  • A little expensive compared to other synthetics.

Get GAF's FeltBuster Roof Undercoat atthe house store.

Best value for money

The best subfloors for roofing in 2023 (4)


Those looking to protect their roofing investment without breaking the bank should consider Grip-Rite's ShingleLayment Roofing Underlay. This affordable undercoat comes in rolls that are 250 feet long by 4 feet wide, allowing users to cover their roof decks for less than most other synthetics.

ShingleLayment is made from polypropylene, giving this synthetic underlayment plenty of strength and durability against the elements. Features a nailing pattern for lid and overlapping nails, promoting a cleaner installation for better water resistance. In addition, the tile pattern printed on the face makes tile stroke alignment easier and more accurate. This roller is not only affordable, but also non-slip. Unfortunately, it is not rated for fire resistance.

product specifications

  • Type:Synthetic
  • Size:250 meters long by 4 meters wide
  • Fire resistance:None


  • Affordable price compared to other synthetics
  • Nailing, overlapping and shingling guides for easy installation
  • Non-slip surface for added safety.


  • Not rated for fire resistance.

Get Grip-Rite Roof Undercoat atthe house store.

update selection

The best subfloors for roofing in 2023 (5)


DIY roofers looking for the ultimate roof protection will want to consider GCP's Grace Ice & Water Shield HT Roof Base. This rubberized undercoat features a peel and stick application process that requires no fasteners and creates a durable watertight seal. It comes in rolls that are 75 feet long by 3 feet wide and has a Class A fire rating.

The HT in the product name stands for High Temperature and indicates that this rubber membrane is suitable for application on the hottest roofs. It is also suitable for roofing materials of all types. It's quite expensive, especially considering the rollers don't offer much coverage, but it's worth it for the level of protection.

product specifications

  • Type:Rubber
  • Size:75 feet long by 3 feet wide
  • Fire resistance:a class


  • Peel and stick application
  • Creates an airtight seal
  • The HT formula is suitable for the hottest roofs
  • Class A Classification


  • Is expensive

Get the GCP HT Roof Undercoat atthe house storethe enamazonas.

better sense

The best subfloors for roofing in 2023 (6)


If felt roofing paper is on the table, Warrior Roofing's 30W Roofing Sheath is worth considering. This 30lb felt layer is made from thick, durable felt that is heavily soaked in asphalt. This combination creates a flat, water-resistant subfloor.

This Warrior Roofing Undercoat comes in rolls measuring 72 feet long by 3 feet wide, providing up to 216 square feet of coverage. It is suitable for tile, slate and tile roofs. It has a Class A fire rating and promotes traction for safety. While the cost per roller isn't high, keep in mind that coverage is low, which makes most synthetic rollers a little more affordable in the long run.

product specifications

  • Type:Sense
  • Size:72 feet long by 3 feet wide
  • Fire resistance:a class


  • High strength sense strongly saturated with asphalt
  • Suitable for use under tiles and slate tiles.
  • Class A fire rating
  • promotes traction


  • Expensive from a square footage perspective

Get Warrior Roofing Coverage Undercoat atthe house store.

best glued

The best subfloors for roofing in 2023 (7)


If someone is looking for peace of mind for their next roofing project, GCP's Grace Ice & Water Shield may be the best product for the job. This rubber covering adheres directly to the deck, creating an airtight seal that synthetics and felt products cannot match.

Grace Ice & Water Shield comes in rolls that measure 75 feet long by 3 feet wide for 225 square feet of coverage. It has a Class A fire rating and is suitable for any roofing material, especially metal roofs that undergo expansion and contraction. The split release paper on the back also helps with some of the challenges faced with rubber covering undercoats. This product is expensive, but the insurance that Grace Ice & Water Shield can provide could be worth it.

product specifications

  • Type:Rubber
  • Size:75 feet long by 3 feet wide
  • Fire resistance:a class


  • Unrivaled watertight sealing with felt or synthetic blankets
  • Split release paper solves some challenges during application
  • Moves with the expansion and contraction of a metal roof


  • Costly subfloor option

Get Grace Roof Undercoat atthe house storeoLowe´s.

best synthetic

The best subfloors for roofing in 2023 (8)


When synthetic undercoat material is chosen, buyers should consider Owens Corning ProArmor Roofing Undercoat. This product's durable polypropylene material resists stretching or tearing from fasteners, yet weighs just 25 pounds for easy portability. It also has the brand's Fusion backliner, which promotes a more secure fit by offering traction for those who walk on top.

Owens Corning claims that ProArmor undercoat is suitable for asphalt and metal roofs. It comes in rolls that measure 286 feet long by 42 inches wide, providing coverage up to 1,000 square feet, although more strokes may be needed to cover as much coverage as a 4-foot roll. However, it has a class A fire resistance.

product specifications

  • Type:Synthetic
  • Size:286 feet long by 42 inches wide
  • Fire resistance:a class


  • Fusion Back Coating to promote traction
  • Suitable for asphalt and metal roofs.
  • Class A fire rating
  • Resists stretching and tearing.


  • Will require more strokes than a 4ft roller

Get Owens Corning Roofing Underlay atLowe´soby Menard.

also consider

The best subfloors for roofing in 2023 (9)


Gaf WeatherWatch Roof Underlayment can be a smart choice for problem areas. Provides protection around areas such as valleys, attics, skylights and other leak-prone areas, as well as roof edges. Users can apply it all over the ceiling, but it is also suitable for use in just those areas before applying a synthetic primer on top.

These rolls come in 50 foot lengths and are 3 feet wide. The rubber backing features a peel-and-stick release film, while the face contains minerals and fiberglass to promote durability and traction during application. WeatherWatch Ice & Water Leakage Barrier has a Class A fire resistance rating, but may be slightly less flexible than other rubber basecoats due to the minerals, which means that warm weather is generally better for installations.

product specifications

  • Type:Rubber
  • Size:50 meters long by 3 meters wide
  • Fire resistance:a class


  • Minerals and fiberglass on the surface for durability and traction
  • Peel and stick application with separate release film
  • It works on the entire ceiling or just on the edges and problem areas.


  • May be less flexible than the typical rubberized base

Get the Gaf WeatherWatch Roof Dock atthe house store.

our verdict

People looking for a premium synthetic cover undercoat should considerGaf FeltBuster Ceiling Basefor its practical pattern and durable construction. However, those looking to save a little money while protecting their investment should consider theGrip-Rite roof underlay.

How We Choose the Best Roofing Undercoats

Choosing a list of the best undercoats for roofs took a lot of work. We had to leverage all of our experience with roofing and the materials we used to determine the most important features that we felt the average DIYer would need. We then performed an extensive product search to find options that met our criteria.

However, that was not the end. We had to look at all these products and compare them based on our experience, materials, price and other important factors. Products that did not meet our standards were discarded, while those that passed received awards based on their strengths.

common questions

That's a lot of information about roofing underlayments, but there may still be some issues beneath the surface. The following section aims to answer these questions as it is a compilation of some of the most frequently asked questions about roofing blankets. Make sure you find an answer to your question below, but if we can't find it, please call your subfloor manufacturer.

qDo ceiling tiles need an undercoat?

Yes. Although tiles are durable, they are just one part of a system. The rest of this system includes subfloor, flashing, drip edges, and other components designed to work together to protect the deck.

qHow is the roof base installed?

It depends on the product, but the roof deck should be rolled parallel to the top of the roof, starting at the lowest point first. Subsequent strokes must overlap on the way to the top. Staple the felt paper in place or use nails for the synthetic base. The rubberized underlay will self-adhere once the liner is removed.

qHow long is the base of the roof?

Roof subfloor lasts 12 to 20 years before it starts to deteriorate. Some rubber subfloors can last up to 35 years.

qHow long can the roof deck be exposed?

The roof felt underlay should be covered as soon as possible. However, a few days with calm weather are usually fine. Synthetic and rubberized undercoats generally last 90 days, but the sooner it is covered, the better.

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