min read

Table Of Contents

When most people hear of roofs, what first comes to mind is the part that can be seen from anywhere - the shingles. It will interest you to know that your roof is not just shingles but a fusion of various combined materials to guard your home from all sorts of harm.

All materials used to make up your roof are essential, but roof decking is the most fundamental of all these roofing components. So, what is roof decking? In simpler terms, it is the basis for your complete roof system. This is why it is of the uttermost importance that if you have plans to get roof replacements or make repairs, you should have an idea of how essential your roof decking is.

This article will help break down all you're expected to know concerning roof decking. By the conclusion of this article, you should have a concise idea of roof decking, ranging from its different types to costs and more.

Definition Of Roof Decking

Roof decking forms the basis of your home's foundation and support for your roofing system. They act as frames upon which every other component of your roofing system is set up on. It is otherwise known as roof sheathing.

Source Of Roof Decking

Most roof decking is made from oriented strand board, OSB in short, plywood which is a natural source, and sometimes, just planks. Oriented strand boards are made of wood strands that are joined together using a waterproof resin that is observed to be the most sought-after due to its low cost.

On the other hand, plywood has proven to be more resistant to moisture and provide better protection, but it is more expensive.

Types Of Roof Decking

Sheet roof decks and plank decking are typically the two types of wood roof decking.

Sheet decking

This type of decking is otherwise known as sheathing. As the name implies, it utilizes flat sheets of wood. Sheet decking can be divided into two types; OSB and plywood.

Oriented strand board (OSB)

This is the most common type used in modern times. It is generally made up of strips of wood that are squeezed together to help flatten it and for size reduction purposes.


This is usually presented in various distinctive thicknesses. The thickness chosen depends on how durable the rafters are or how you want them to be. Even though OSB is standard, some homes are also using plywood up to this day.

The two types of sheathing are good options; choosing which one to opt for depends on how much you are willing to put into the project and the kind of wood available.

Plank decking

This type of decking used to be predominant before the introduction of plywood. It comprises long wooden boards in various sizes, which could be 1x8 or 1x6. However, it is not predominantly spoken about because people use it less these days. Very few roofs still have plank decking as their roof foundation today.

When Should Roof Decking Be Replaced?

You may also have to invest in decking replacement whenever you consider replacing your roof. When you notice signs of rot or feel the roof is no longer strong enough, you need to consider replacing the wood.

Often, this is something you need help to determine. You will need the assistance of your roof contractor. Your roof contractor will often have to remove your old roof to confirm how much replacement needs to be done.

If they come across rotten boards, a decking replacement must be done before other roofing materials are set up. Sometimes, your roof contractor might check and find out that the integrity of your decking hasn't been compromised. If that is the case, it can continue to support any new roofing component that needs to be installed.

Causes Of Rotted Roof Decking

Roof decking is made from wood and its composites, so water is one of its significant enemies. When your roof deck is continuously exposed to excessive moisture, it becomes vulnerable to wood rot, one of the most crucial damages that water can exert on wood.

When your shingle roof is worn out, roof gutters overflow, and accumulation of snow that could eventually lead to ice dams, rising attic temperatures, and poor roof ventilation can all lead to water seeping into your roofing system. When this happens, your decking's integrity will eventually be weakened, giving rise to roof deck rot.

Signs of rotted roof decking

Several signs indicate that your roof deck has begun to rot. Some include:

  • Leakage from the roof.
  • Spots that are wet on the ceiling.
  • The wallpaper begins to peel.
  • Roofline begins to sag.
  • The interior walls start to stain.
  • Mildew in attics.
  • Rafters showing water stains.

The most notable sign of damage done to the roof decking is roof leakage. This particular problem can give rise to spots on ceilings and rafters showing water stains. Weather conditions are natural, and your roof is continuously exposed to it.

Thus, you should get an expert roof inspection at least twice a year. It should be checked at least once after the fall and spring to avoid the dangers of snow and ice. After a natural disaster like hurricanes and sometimes storms, you should inspect your roof to ensure it doesn't suffer any damage.

Can Roof Decking Affect Ventilation?

You must know that ventilation is equally as significant outside the home as it is inside. Therefore, ensure that the roof decking doesn't sag between the rafters to afford good ventilation and roof durability. When there is no adequate ventilation in your attic, it could lead to roof sabotage due to the effects of water and very harsh tropical conditions.

The effects of moisture can lead to the breakdown of decking. When this occurs, the roof decking will no longer be able to support the roof's weight in cold times because of snow. Hence, you have to start planning for a new roof decking.

Cost Of Roof Decking

Getting the exact cost of roof decking will be unfeasible. This is because of the unsteady price of wood. In the year 2021, there was a hike in wood prices, which led to a massive increase in roof installation and replacement costs. The price of plank decking is usually measured per linear foot, while sheathing is done per sheet.

Essentially, a professional can only quantify the exact roof decking cost. Therefore, to ascertain the actual cost of roof decking, it is best to consult a roofing contractor to evaluate the kind of roof decking you need and the quantity to be replaced. People often ask if you can replace the decking without touching the entire roof.

The answer to this question is not exactly. Roofing materials are always attached to roof decking, so if you have to replace the decking, you have to remove and reset the roofing materials.

Roof Decking Services

If you plan to replace your roof or install a new one, or perhaps there is an area that's damaged and needs repairs, ensure you acquaint yourself with the pricing and the level of work needed by a professional.

It's also an excellent idea to familiarize yourself with roofing concepts. This will help you during the inspection of your roof when moving into a new apartment or even constructing a new roof.

As is apparent, roof decking is something you should try to do yourself only if you are a roofing specialist. Contact a reliable roof contractor to help with your roof decking needs regardless of your type of roofing.

Roofing services in Boston
Call the exteriors expert that cares!