The best subfloors for roofing in 2023 (2023)

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.

Sense

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

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.

Synthetic

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.

Climate

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.

Installation

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.

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.