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Blog: Blog2
  • Writer's pictureKelsey Reyes

We Roof Philly Blog: What Makes a Roof a Roof?

Updated: Nov 1, 2021

What specific elements make up the composition of a roof? If you're talking to someone about repairs to the roof on your property, it can be useful to know the terminology involved. Of course it's more than just knowing the words--it's also important to know the difference in the materials and labor that go into, say, updating your roof system versus replacing your decking. With this knowledge, you can have a better understanding of the work roofers may be doing on your property and have a clearer idea of what cost and labor should reasonably be.

Here, we're not going to get too technical, but we will give a general overview of three main components of residential roofs.


Let's start at the bottom of the top: the rafters!

Rafters support the load of the roof. They work together with ceiling joists to bring your ceiling, walls, and roof together to cover your home. Here, they can be seen to the right of the image and extend underneath the roof decking to the back and left as well.

Some people's homes may have trusses instead of rafters. The only difference between them really applies in the construction of new homes, as their maintenance and quality is generally otherwise the same.

If your roofer is having to get all the way down to the rafters, you probably have some big roofing issues needing to be addressed. Aside from catastrophic events, usually issues that involve stripping a roof to the rafters are ones that have been brewing for a long time. Regular roof inspection and maintenance is imperative in order to avoid costlier repairs like this later on.


You probably realize there's got to be something between, say, your rafters and your shingles, but you may not know what that part of your roof is called. Well now you know--it's the decking!

If your roof repairs involve going a little deeper than the outermost materials, they're probably going to be about your decking. Decking is like the sandwich meat between the rafters (or trusses) and the protective materials on the outside. It also serves, simply put, as a structure to hold all the stuff that goes on the outside.

Most residential homes use wood--often plywood--for the roof decking. If you're thinking plywood doesn't seem like it'd get the job done, you'd be surprised at how well it can hold up. Additionally, it's important that the decking has a little give, so wood is an excellent material for the job.

That being said, you can also see how leaks getting through from a poorly maintained roofing system could quickly cause much bigger problems if it is given the opportunity to affect the wood below.

Roof System

Finally, we get to the part most people think of when they think of roofing issues-- your roof system.

Your roof system is all that stuff on the outside, above the rafters and decking, that keeps your home protected and leak free. In another post, we outline the different types of roof systems in greater detail, but for now, it's enough just to know what's being discussed if your roofer or contractor says your roof system needs work.

Roof systems can be anything from different types of shingles to metal to various membranes, depending the type of roof you have, so cost and labor can vary widely. However, it's important to keep in mind that a healthy roof system will often be the most important key in maintaining a healthy roof overall.

Your decking and rafters will rarely, if ever, need attention if your roofing system is frequently checked and maintained so that it can properly insulate and weatherproof your home.

How to protect the components of your roof

If all this talk of maintenance is making you wonder about the state of your roof, a good idea would be to contact a roofing company you trust, like We Roof Philly, for a free estimate sooner rather than later. It's hard to make informed decisions about the integrity and longevity of your roof without an expert's assessment. (And since estimates are free, you have nothing to lose!)

That being said, some things you can do yourself, if you have access to your roof, are to be sure it is clear of debris and make note of any standing water if you have a flat roof. (Roof types are covered in a previous post.)

If you do see any issues or notice any leaks, contact your roofer immediately, as the sooner you address problems, the easier (and cheaper) they will be to correct.


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