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20 Parts Of A Roof And Understanding Their Functions

The foundation may be the most important part of a house, but the roof is a close second. A house’s primary function is to protect you from the elements, and it’s the roof that actually accomplishes (or fails to accomplish) that goal. A sturdy roof will protect you from rain, snow, wind, heat, cold, and everything in between. A bad roof will leak, wobble in the wind, collapse in the snow, and generally be a headache for as long as you own the house.

Rain Gutter Downspout Splash Block

That leads to the second reason why it is so important to have a sturdy roof. Repairing a compromised roof will be insanely expensive and also time-consuming. You don’t want to ever be in the position of having emergency repairs done to your roof if you can avoid it.

How to Choose

One of the ways to figure out what kind of roof to choose is to first learn about all the different component parts of a roof. Once you learn about all the parts that, put together, form a roof, you can advance your knowledge so that a leaky roof will never happen to you! While reading through this list, you’ll need to keep in mind that all roofs are different. The precise structure on one home or building may vary slightly (or greatly) from another home or building. Having said that, it is a good bet that you’ll find most, if not all, of these components to be crucial to your roofing repair project.

20 Parts Of A Roof And Their Functions

1. Truss

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This is the name for the overarching roof section that consists of many of the parts you will read about below. A “truss” is formed from many pieces, such as rafters and ridge rafters. The truss supports the covering, sheathing, underlayment, insulation, and any other components that might be added to the roof, such as a skylight or chimney. You can think of a truss as a system that supports the roof.

2. Covering


The covering is a generic term for anything that is nailed or secured down onto the rafters and actually keeps the elements out. The covering can be made of many materials, such as iron, tile, slate, or synthetic lining. It must be both lightweight and impervious to substances such as the different weather elements, sleet, bird droppings, dirt, wet leaves, and the muck that accumulates on a roof over time. Your choice of a covering will depend on many factors, such as your budget, the weather where you live, and the type of house you are constructing.

3. Rafters

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You will find rafters running from one end of the roof to the other and forming the support system for the rest of the roof. Rafters are typically made from wood, as it is a strong, pliable material, but you will also find them made from metal, especially in industrial buildings and high rises. The rafters support everything else, from the insulation to the covering.

4. Fascia

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Algae Resistant Desert Tan Hip and Ridge Asphalt Roofing Shingles – Homedepot

The fascia is a relatively superficial item on roofs that runs parallel to the ground along the roof’s edges. It is fixed to the rafters and may also serve as a support for the gutter. Many homeowners like for the fascia to be aesthetically pleasing, so as to contribute to the facade of the house and thereby increase the value of the property. Homebuilders on a budget often decide to scrap a fancy fascia for a more budget-conscious option, and oftentimes simple wood will do the job, provided it is treated and painted.

5. Ridge

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A ridge is found on specific types of roofs, including pitched, gambrel, gable, and mansard. For example, a pitched roof is a very common roof found in many suburban houses. It forms the classic upside down ‘V’ shape. The ridge is found at the highest point of the roof where the two different sides intersect. You might liken the ridge to the “keystone” of the roof.

6. Ridge Tile

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The ridge is a point where two different continuous sections come together. It therefore has a gap, and this gap can be infiltrated by uncontrolled elements, especially rain and animals. To prevent this, ridges are often tiled to prevent the entry of these elements. Sometimes the ridge tile is meant to stand out from the rest of the roof, and sometimes it will have the same exact tiling or shingling as the rest of it.

7. Eaves

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Galvanized Steel Eave Drip Flashing – on Homedepot

The eave of a roof is the lowest point of a roof. In a pitched roof, it is the point that is farthest away from the ridge. This is the spot where rain drips off the roof, which makes it the ideal spot for gutters. This is also the last point on the roof with singles, so it is often the point where shingles begin to peel off in a windstorm or deteriorate from rot.

8. Valley

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While not every house or building will have a roof with a valley, they are still somewhat common. The valley is the point of connection between two pitched roofs and forms a right angle. This will appear as a ‘V’ to onlookers. Because it is a valley, it is incredibly common for rainwater, leaves, and other debris that might collect. For that reason, valleys are often equipped with gutters of their own to transport the garbage away.

9. Downspout

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Available on Amazon.

The downspout is the pipe that connects to the gutter and runs vertically from the roof to the ground. It’s function is to channel the rain water to the designated point of outflow. It is usually made of metal such as galvanized steel, but may also be made of plastic. Downspouts are incredibly important to a properly functioning roof as their malfunctioning may defeat the whole operation of the gutter system.

10. Ceiling Joists

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Ceiling wood beams – on Amazon.

Ceiling joists are almost always planks made of wood. You will find them running along the rafters. They are used to improve the rafter’s strength and to support the soffits like an arch, balcony, or eaves.

11. Soffits

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HardieSoffit Primed Fiber Cement Vented Soffit – here

The soffit can be found between the wall, fascia and eaves. A soffit conceals the rafters and ceiling joists. Its purpose is mostly to keep the elements out and to insulate the building.

12. Underlayment

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2in1 Silent Vapor Barrier Underlayment – here

The underlayment consists of a waterproof material typically made out of a synthetic sheet, rubber strips, and felt. It is placed over the substructure of the roof but under the shingling so as to ensure the roof is waterproof and insulated against the weather.

13. Battens

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The battens, also known as lath for roofing, are made from wooden or metal strips holding tiles and shingles in place. The spacing of the battens is essential to correctly and securely installing tiles and shingles. Battens are installed horizontally and, depending on the type of roofing, the spacing can vary.

14. Shingles

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The singles are the first barrier against weather elements and so they must be tough and as weather resistant as possible. Shingles are often made from a thick, tar-like product that is resistant to rot but can also be nailed into place. The two most important considerations with shingles are the weight and the weather resistance. Obviously, we want shingles to be as light as possible, but we also don’t want them giving way to the rain. Sometimes you’ll see wooden shingles on older houses, but those are being phased out due to lack of durability.

15. Skylight

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VELUX Fresh Air-Venting Skylight Window – available here.

A skylight is a luxury feature that you might see on some houses or buildings. It is effectively a window but on the roof. Installing a skylight can be a complicated process, and it is also somewhat risky, as a skylight is more likely to leak water than no skylight. Having said that, they are a great feature to add onto a roof, and allow the interior of a house to illuminate with natural lighting. If you are considering a skylight for your roof, make sure that it is properly sealed and insulated so that you don’t have any leaking.

16. Chimney Flashing

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Duratech 8′ Large Base Adjustable Roof Flashing – on Amazon

Chimney flashing is a metal sheet that is placed between the chimney and the roof, as well as the rest of the house, in order to insulate the heat and prevent the roof and house from catching on fire. The flashing is an absolute necessity and if it is installed wrong, it leaves the way open for fires.

17. Felt Underlayment

Felt Underlayment
Laminate Underlayment with Attached Vapor Barrier – found here.

The felt underlayment is usually found beneath the shingles, and it should be considered to be a part of the greater underlayment. The underlayment’s job is to insulate the house from the elements, and the felt underlayment provides extra insulation. Because it is felt, you will find it placed underneath synthetic material so that it will not get wet.

18. Insulation

 Radiant Barrier Insulation
US Energy Products Radiant Barrier Insulation 1000 sqft – check it here.

The insulation in a roof is one of the more important components. Most people know that a house or building is insulated, but fewer people think about roof insulation. Despite this, it is just as important to insulate the roof as the walls. If a roof has shoddy insulation, heat will rise right out of the roof, disappear, and the house will be cold all winter long! If you go into the attic of a roof, you may be able to see this insulation. It will often look like cotton, or maybe like a thick spongy material. Whatever you do, do not poke it or otherwise tamper with it. This will compromise the insulation and it will lead to terrible climate control and high energy bills.

19. Gutter

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GutterStuff Guard 5-Inch – Available on Amazon.

The gutter is the long basin that is attached to the eaves of the roof to catch rain and melting snow. It is usually made from galvanized metal or plastic. Gutters are tricky because it is very easy for leaves to get caught in them and clog up the drainage of rain. This will then cause the water to backup and overflow the gutter, potentially seeping into the roof and rotting the shingles and the wood.

20. Splash block

Rain Gutter Downspout Splash Block
Suncast SB24 Rain Gutter Downspout Splash Block – Available here.

The splash block is a facing placed on the roof to guard against overflow from the gutters. It is usually made of plastic or galvanized metal to prevent rust from taking place. The splash block is almost as important as the gutters since overflow from the gutters and seepage into the roof will cause leaks, problems with insulation, and roof rot.

How to Care for Your Roof

It is quite common for downspouts to become unmoored or unplugged in bad storms, especially windstorms, and they should be checked for sturdiness regularly. You should also invest in high-quality gutters, inspect, and clean them regularly. Failing to do this may leave you with clogged gutters, a seeping roof, and rotting shingles.

When it comes to splash blocks, an ounce of prevention is worth the while. Failure from the splash blocks may end up forcing you to replace your whole rotting roof. You should do whatever you can to avoid this, so make sure you invest in high-quality gutters and splash blocks.

You should also remember to have your entire roof inspected bi-annually or on a yearly basis, depending on the weather conditions in your area. This will save you money in the long run if you can make repairs as soon as you notice any damage.


Now that we’ve covered all the parts of a roof, we hope you have learned about more than what shingles look like. It is quite likely that many people simply imagine shingles when they think of a roof, but it isn’t the only essential component of a roof. Understanding more about your roof is vital for anyone that plans on doing roofing work, needs roof repair or is involved in any area of construction.