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Your Ultimate Guide to the Different Roof Parts



Learn Roofs Inside Out from this Comprehensive Guide


We all need a roof over our heads, but what are the parts of a roof called? Knowing your roof parts is a good way to keep up with contractors, showing that you understand the field so they don’t attempt to take advantage of you. Understanding the different parts of a roof also gives you an advantage when seeking repairs or replacements, as you can ask for exactly what you need with more confidence, leaving less up to guesswork.

We’ve put together this guide on the different roof parts’ names, along with what the function of each part is, so you can feel more secure talking to roofers and repairmen from now on.

Note: This list is mostly applicable to sloped roofs, with flat-roofed homes having far fewer features.



1. Asphalt Shingles

These are the roof components that you’re likely to be most familiar with, being the parts of the roof that most commonly need to be replaced. Most shingles are essentially asphalt and fiberglass tiles, which can come in either the 3-tab or architectural variety, providing your roof with protection against rain, wind, and the elements in general. Shingles can also take the form of other materials, with some homes featuring traditional tiles, wooden, or metal shingles, among others.



2. Felt Underlay Membrane

Underneath the shingles, you’ll find the felt underlay membrane. This is essentially the final layer of protection from the elements for the roof decking (more on that next), also offering protection to the shingles of the roof from the resin that the decking might release. The underlay will generally be made of some sort of synthetic or composite felt and should be waterproof to some degree for maximum efficacy.



3. Roof Decking / Battens

One of the most important parts of a house roof is that it gives the structure some real body. The decking is essentially a fairly thin plywood board that’s laid over the frame of the roof, so the rest of the elements can be installed. Think of it sort of like the floor of the roof.

Alternatively, this part of the roof can be set up with battens on top of the decking. Battens are essentially extra planks placed on top of the decking for shingles to be installed onto directly.



4. The Eaves

Eaves are the name given to the edge of the roof that sticks out, hanging over vertical walls to prevent them from coming into contact with too much rainwater. The dangers of water damage are well recorded, which makes it clear why good eaves are so important to a well-maintained roof and home.



5. The Gutter

The gutter sits beneath the eaves, collecting all the rainwater runoff from the roof and funneling it through the downpipe. It’s important to keep an eye on and regularly clean your gutters, because if they become blocked with leaf matter or debris it could cause leaks, drippage, and splashing that could end up damaging the external walls of your home.



6. Downpipe/downspout

With every gutter, there must be a downpipe. The downpipe is essentially a closed gutter that runs down the side of the house, leading down to a drain, ensuring that water doesn’t just pool up near the house.



7. The Ridge

This is the name given to the top of a house roof, where the two diagonal parts of the structure meet. The ridge of the roof has to be lined with its own layer of shingles to ensure that it doesn’t become compromised by winds or water damage. Under these shingles is a ridge board, made from wood or metal, which is where the rafters/trusses meet under the decking.



8. Rafters/Trusses

The rafters or trusses are essentially the boards that give the roof its structure. They run from the main structure of the house up diagonally, meeting at the apex of the roof, giving roofs their typical triangular shape.



9. Joists

Joists run horizontally across the width of the roof, meeting the bottom ends of the rafters in the structure. The joists are essentially the basis of the structure of the indoor ceiling. Joists are also found supporting dormer windows.



10. Purlins / Collar Beams

Purlins run perpendicular to joists, positioned slightly higher up, and connected to the bottom of the rafters/trusses. They provide further support, keeping things steadier than the rafters and joists alone. Purlins are also known as collar beams.



11. Flashing

Flashing is a protective element that can be found in every part of a roof where you might find joints. It’s generally a type of metal sheeting made from galvanized steel or aluminum, or sometimes plastic, that’s used to keep water from penetrating the roof through openings. You’ll find flashing in the valleys of the roof, along with the bases of chimneys, roof vents, plumbing vents, and walls.



12. Chimney

The chimney is a vertical column that comes out the top of the roof, providing a place for smoke and combustion gas to leave the house. Chimneys generally lead up from fireplaces, boilers, and indoor stoves, designed for ventilation so homes aren’t filled with smoke or dangerous gases.



13. Plumbing Vents

The plumbing vent of the roof is a pipe that comes out the top of the house, designed to allow airflow into the plumbing system. Plumbing requires air to operate properly, as it allows wastewater to flow into the sewage or septic-system leaching field.



14. Roof Vents

Along with the chimney and plumbing vents that release gases and pull in air for the sake of operations within the home, there are also roof vents designed for the simple ventilation of the attic space. The best roof vents are made to stand above the highest point of the roof, with four open sides to allow airflow in from every direction. Made from perforated aluminum, they lead to air inlets at the base of the roof, bringing air into the attic to ensure that it’s well ventilated.



15. Valleys

The valleys are the points on roofs where two opposing slopes meet, such as the joint between the primary roof and a dormer. Valleys require their own underlayment and flashing to stay safe and secure.



16. Dormer Window

A dormer is a window that sticks out vertically from the side of the primary roof, with its own walls and roofing set up. It’s built from lookout boards and its own smaller rafters/trusses. The rafters of a dormer are formally known as rakes.



17. Gable Window

As an alternative to the dormer window, a gable window is installed directly into the walls of the house, rather than into a separate vertical structure. A gable window can offer a view of the outside world from an attic or upstairs space in the home.



18. The Attic

The attic is the space underneath the main decking of the roof. Even if you can’t go in there, every home has an attic, while some are bigger than others and with more purpose. Some people use their attic to set up a new bedroom or for storage, while other attics may simply exist as a space under the roofing parts.



19. Skylight

A skylight is a window installed directly into the roof, facing upwards rather than outwards like a gable or dormer window. They can be very handy for getting some light into attic bedrooms, or in the upstairs rooms of converted bungalows, while they’re also often used as stylistic choices in more open spaces in homes with higher ceilings.


Final Thoughts

There are so many elements of roofs that we couldn’t fit all of them into this article, but with what we’ve explained to you here, you should feel far more confident when entering discussions with contractors, roofers, and repairmen. It’s also worth remembering that not every home is the same, so while many of these elements will undoubtedly feature on your roof, there will be others that don’t.

With all of this information, you can debate and negotiate easier than ever, but remember it’s not your responsibility to be an expert on roofing, and a good contractor should guide you through the process with empathy.

If you need a trustworthy, reliable roofer, Get in Touch With Us, we’ll make the process as smooth and easy as we can.