What is Decking on a Roof and Its Components

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For those who aren’t familiar with house structure, they may not know what is decking on a roof. In fact, decking is an integral part of roofing as a whole. To explain in a simple way, roof is constructed from trusses as the basic framework and joists as the baluster that support and distribute the weight of the roof.

However, the space between the trusses and joists as the frame is empty. Roof decking is the extra layer that attached to them, the flat surface that serves as protection between the roof and the home. It also contains weatherproofing features such as underlayment, shingles, and other attached.

What is Decking on a Roof?

What is decking on a roof exactly? Roof deck is the material that sits amongst the trusses and joists as the structural components, as well as the weatherproofing and insulation layers such as coatings, roof materials, layers, etc.

What is Decking on a Roof

Basically, roof deck is a section where any other materials of the roofing is placed.  Roof deck should be strong and durable enough to support the weight and cope against various conditions.

See Also : What is a Rake on a Roof

Roof Decking Thickness

Besides knowing what is decking on a roof, it is also important to know the typical thickness of it. The common thickness for roof decking is under ½ inch, or about 7/16 inch to be exact. It is possible to find 3/8 inch plywood roof decking installed as this measurement once is considered as adequate and acceptable, however it won’t be as sufficient as the ½ inch ones.

Having a 3/8 inch of roof decking layer is not a defect to the structure; however as a home owner you have to be aware of it. Some regions and states even have specific jurisdiction about being aware of the roof decking thickness from the constructor at the time being, if the house is built using the old standards.

Types of Roof Decking

Now that you have learned about what is decking on a roof and its standard of thickness, it is time to dive further into the topic by understanding different types of roof decking and what is roof decking made of. There are several common materials used for the deck such as wood, concrete, cement, or steel.

It depends on the supported weight and affect the material that should be used. Other variables like rain, snow, and air conditioning weight might be added into the calculation.   

For residential buildings

Plywood, groove wood, or tongue system is the most typical type used. Wood in general is strong enough to hold any type of roofing material weighs but it might need extra reinforcement for tile material.

For industrial or commercial buildings

Cement, concrete, or steel are more commonly found. The reason is because these buildings usually have larger structures so they naturally need stronger structure to carry the equipment with more weight on the roof.

Whatever types of roof decking you are planning to use, keep in mind t the matter should be turned over to the professional expert in roofing system. Having the installation done improperly might cause dangerous impact in the future.

Roof Decking Boards

Moving on to the next part of roof decking system, the following list below will help you understand about what is decking on a roof board and several of its types.

Tongue and groove

It is a board in 2×6 formation that consist of “tongue” on one of the board’s edges that fits into the “groove” on the edge of different board. The boards are slid together. It is common to be found in houses without ceilings, in which the boards add architectural elements to the joist.

Plank decking

It is comprised of planks and shingles that layered and placed in 1 ½ inch of distance between one another. It is most often found on old houses as it is an old decking solution.

Step decking

This roof decking board also consists of distanced planks, but the boards are placed perpendicular to one another. It lets the air to flow between the spaces under the shingles. The space between shingles installed may vary. It is used if you are installing cedar roofing shingles.

Plywood decking

The boards are typically sized around 4×8 ft with plywood materials, which made from rigid, moisture resistant, and mature trees. Having knots in the plywood may result in less uniformity.

OSB decking

OSB stands for oriented strand board. OSB decking is the most used roof decking type in the modern buildings. The boards are about 16 ft or longer sometimes. The boards are made from interweaved and bonded wood strands, which created from rigid, moisture resistant, and small trees.

You may need to learn about what is decking on a roof and its details if you want to replace your decking. Decking replacement doesn’t exactly equal as replacing your whole roof. Discussed with professional and experts in roofing system to determine how much and what sections of your roof decking that need to be refined.