The Importance Of Roof Sheathing

When most homeowners consider roofing parts, they probably think of shingles, gutters and maybe insulation. However, one important roof layer is often overlooked: the sheathing.

Roof sheathing is also known as roof decking. It is a crucial part of the entire roof structure as it helps to prevent an array of different issues and damages.

In addition to that, sheathing a roof can also help you prolong the roof’s lifespan and make your home more energy-efficient.

Read on to learn the proper roof sheathing definition and discover several reasons why roof sheathing is such a crucial component of your roof.

What Does Roof Sheathing Do?

So, what is roof sheathing, and what does roof sheathing do?

Roof sheathing or decking is an important layer of the roof that sits hidden underneath the top layer of shingles, which means that shingles are attached to these squares or planks of wood. It is most commonly made out of plywood in the form of planks or roof boards. 

Before plywood and OSB boards, a long time ago, tongue-and-groove boards were used as roof sheathing material (nowadays, tongue-and-groove boards are used for decoration purposes).

These boards can be installed in two different ways and based on the installation method, we can differentiate between two types of roof sheathing. The sheathing can be either open, with gaps between the roof boards, or closed, with no gaps between them. This closed sheathing is also called solid sheathing.

The open sheathing is generally lighter and lower in cost, but solid sheathing panels are more efficient in protecting your roof from leaks; therefore,they are a better option for residential construction. 

One more type of sheathing besides open and solid sheathing is concrete sheathing, which is considered a heavier material for roofs that need more strength and durability for heavy loads. In order to withstand heavy loads on the roof, metal reinforcement is added to the concrete sheathing.

Also, sheathing can be made out of wood panels too. 

However, ultimately, the type of sheathing you and your roofer opt for will depend on the needs of your roof structure.

A Middletown roofing contractor can ensure that a homeowner’s sheathing is always properly installed and maintained.

What Benefits Does Roof Sheathing Offer? 

The benefits of roof sheathing are tremendous. First of all, it adds strength and stability to the roof, which makes your home safe. Also, without sheathing, your roof would be more prone to leaks. Furthermore, roof sheathing helps with weight support, so your roof won’t sag due to heavy snow load. Still, if a massive tree branch or limb falls on the roof due to severe weather like storms, sheathing can be damaged.

Last but not least, roof sheathing (or decking) helps with fire protection since its material is covered with fire retardant treatment, while concrete sheathing is fireproof material by itself. 

What is the Minimum Thickness of Roof Sheathing? 

The minimum thickness of roof sheathing is between 1/2” and 5/8”, depending on the snow load in the area where the new roof is installed. However, the roof minimum thickness is ultimately a decision of the roofing contractor who is in charge of the roof installation. He should have the knowledge and experience needed to decide how thick the panels of your roof should be.

Roof Leak Prevention

Before sheathing became standard on new roofs, most roofs simply had a layer of boards underneath the shingles. The spaces between the roof boards were highly prone to leaking, and water damage was rampant on most roofs.

Sheathing solves this problem by providing a more continuous, solid layer beneath the shingles that has far fewer gaps or spaces. Proper sheathing is often the key difference between a roof that constantly leaks and a roof that hardly ever does.

Anchorage for Shingles

The sheathing layer is also a vital part of the support and structure for the rest of the roof. It provides an anchorage for the shingles to be firmly nailed to and, overall, an excellent foundation for all the external roof materials.

All these materials, namely asphalt shingles, metal panels or shingles and similar, are smaller in size and require a broad and sturdy base where they can be safely and firmly attached. Sheathing provides great support for this exact purpose.

Roof sheathing thickness, i.e. the thickness of the plywood boards is also an important consideration here. Their common thickness can vary and reach as much as 5 inches. And the thicker the boards are, the heavier and sturdier they will be.

This is important because heavier shingles will need heavier sheathing to support them adequately. Your roofer will ensure that the sheathing is as thick and sturdy as it should be, providing optimal structural support to the shingles.

Structural Support for the Entire Roof

In addition to anchoring the shingles, the sheathing provides broader roof support by evenly distributing any extra loads the roof may carry.

This includes snow and other accumulation. It also allows more hardware, such as solar panels, to be safely mounted on the roof without causing damage.

Roof sheathing is one of the first elements a contractor is likely to inspect when planning a solar or HVAC installation, for example. This is because the sheathing effectively disperses this extra weight across the rafters and other supporting elements of the roof. It prevents sagging and partial roof collapses.

Roof sheathing thickness and dimension are important aspects here as well. The sheathing planks can be as little as one inch thick and as much as five inches thick. The thinner planks will decrease the overall weight of the roof as well as its cost, and the thicker ones will increase them.

Your local roofer will advise you on the best solution based on the state of your roof, its needs, the weather your area gets, and the amount of support the roof requires.

Generally, thicker sheathing will provide better load tolerance, as well as overall durable and long-lasting protection for the entire roof and your property.

When Can the Sheathing Board Get Damaged? 

As we mentioned somewhere at the beginning of this text, sheathing boards can get damaged due to stormy weather, when massive tree branches can fall on asphalt shingles and damage them and sheathing boards as well. This board damage is a result of a heavyweight concentrated on one side of the roof. And while this damage is less likely to occur with roofs that have been recently installed, old, worn roofs that are ready for roof replacement are more susceptible to this type of damage. 

If you aren’t sure whether the sheathing of your roof is damaged, the best way to check that out is to schedule a professional roof inspection. Also, if your roof is visibly sagging, the sheathing is most likely damaged, and the roof will need a replacement, but a professional inspection will give all the answers to whether it can be repaired or whether roof replacement is the only option. One more telltale sign that your roof sheathing has an issue is the light passing through holes in your roof, which you can see if you are inspecting the roof from the attic

Reflective Roof Sheathing for Cooler Home

Reflective roof sheathing functions to provide better thermal protection for homes by reflecting the sun and preventing the attic from overheating.

The attic is known to overheat during the summer because the sun’s energy is absorbed by the shingles and therefore transferred to the attic. This, in turn, causes the entire home to heat up more, leading to higher cooling needs and energy consumption.

With reflective roof sheathing, on the other hand, the heat transfer from the shingles to the attic will be significantly decreased, leading to a cooler home, lower energy consumption, and reduced cooling costs.

This can all be achieved simply by installing a radiant barrier on the sheathing. The radiant barrier will help make the home more energy-efficient, which is especially useful in hot climates or on buildings in such climates that may have less insulation.

Roof Sheathing Installation

Sheathing a roof is a crucial process in installing a new roof or replacing your old one because, together with shingles, the sheathing works to fully protect your roof from leaks and water damages.

Roof sheathing is also an important roof element to inspect and maintain on a regular basis. 

Properly maintained shingles should adequately protect the sheathing from water and exposure. However, if the shingle layer becomes damaged or if shingles are torn or missing, the vulnerable plywood sheathing may be exposed. 

Even if the sheathing does its job to prevent leaks, water may soak into the plywood, leading to rot and failure. Ensuring the sheathing is in good condition is an important part of any professional roof inspection. Have a question regarding roof repairs or skylight installations? Or if you suspect your home has damaged or old sheathing,  ask a roofing professional from Fortified Roofing of Middletown NJ, for help.