Roof and Their Functions

24 Parts of a Roof and Their Functions

While the foundation is arguably the most important part of your home, the roof comes in at a close second. Your home’s main function is to protect you from the elements, and it’s your roof that will or won’t help you accomplish this goal. A sturdy roof that is in good repair will protect you from cold, heat, wind, rain, snow, and anything in between. A roof that isn’t in good shape will wobble when it gets windy, leak, collapse during snow, or be a headache in general as long as you own your home.

This leads to another reason why it’s so important to have a very sturdy roof. Repairing a compromised roof can be an extremely time-consuming and expensive process, and this is why it pays to know the different parts of the roof and their functions. You never want to be in a position where you have to take off the roof for a new one, so keeping all of the parts of the roof in good shape is key.

Roof and Their Functions
Roof and Their Functions – Raise the Roof by Brian / CC BY 2.0

One of the ways to do this is to learn about all of the different parts of a roof. Once you learn them, you’ll be able to see how they all fit together to form a roof. We’re going to highlight some of the most important parts of a roof for you below, and you can see how they work to keep your home dry and safe in any weather.

1. Ridge

This part of the roof is technically called the ridge board, and it’s the horizontal piece of metal or wood that rests at your roof’s peak. In turn, this is the part that will help create the triangle on your roof’s structure. Technically speaking, this is the highest point of your roof. For function, the ridge or ridge board connects to the roof’s trusses and rafters to help build up the roof’s frame and make it more solid. You may also hear people call this part of the roof the roof beam or board, and it encompasses the whole part that forms the roof’s ridge.

2 Ridge
Wandle/Dairy by Images George Rex / CC BY-NC-ND 2.0

2. Shingles

You can think of shingles as flat roof covers that come in rectangular and flat shapes. Your contractor will install your shingles at the roof’s eaves after they place the roof decking. Depending on the design of your house and the location, you can pick from several different weatherproof materials. These materials include but are not limited to slate, flagstone, wood, plastic, metal, and other composite materials. Solar shingles are also gaining traction. The main function of your shingles is to stop water from seeping through the eaves. To make it 100% waterproof, the contractor will also have to apply shingle underlayment to this part of the roof before laying the shingles down.

3 Shingles
Shingles by Via Tsuji / CC BY-NC-ND 2.0

3. Soffit

The soffit is one part of the roof that you can consider functional, but it’s also very aesthetic. This is the roof structure that you’d see if you straighten your roof up. It’s put between the roof’s eaves and the wall, and it works to conceal the rafters and the ceiling joists. The main function of this part of the roof is to protect the rafters from natural elemental issues like mold or moisture to keep them strong and rot-free for years. In turn, it also helps all of your roof materials last longer, and this means that you’ll have less general maintenance to worry about over the life of your roof.

4 Soffit
Fascia & Soffit Replacements by T.K.F. Handy Construction / CC BY-NC-ND 2.0

4. Valley

The valley part of your roof connects two sloped or pitched roofs to form a 90° angle. It works to support the valley rafter, and this part will support your roof’s internal gutter where small debris and water will trickle down to reach an external gutter system to get it out of the house. In short, this is the roof valley that collects the water that falls off the roof and gives it a funnel to fall down into the gutter system. This is why picking out the correct installation type for the valley on your roof is critical. If you don’t, it’s easy to end up with severe leaking issues that damage the whole roof’s structure.

5 Valley
Lightwater Valley 092 by Jeremy Thompson / CC BY 2.0

5. Truss

The truss is one name for the part of the roof that overarches, and it connects to many other parts of the roof. A truss uses many pieces to form, including ridge rafters and rafters. The truss works to support the sheathing, covering, insulation, underlayment, and other other components that you may have added to your roof. This includes a chimney or skylight. The truss is the system that supports your roof, so it’s typically made out of metal or very thick wood components that are strong enough to bear the weight of the roof.

6 Truss
Trusses by Bryn Pinzgauer / CC BY 2.0

6. Eave

The eave will be the lowest point in  your gabled, pitched, or mansard roof styles. You may hear them called the roof edges, and they tend to overhang from the wall’s face to project from the side of the house. This gives the house more protection when it rains or sleets as the water won’t be running straight down the walls. Instead, there will be a foot or so of space due to the eave hanging out. This portion is where the gutters connect to the roof, so the main function is to clear the wall so water doesn’t damage it by constantly running down it.

7 Eave
Eave by Mish Mish / CC BY-NC-ND 2.0

7. Flashing

Flashing can come from different materials, including galvanized steel, aluminum, and plastic. The main function of this part of the roof is to stop water from getting through any openings in the roof and other critical areas where it could pool. You’ll typically find it mounted on roof valleys, skylights, chimneys, and vents. There are several different types of roof flashing available, and they include:

  • Chimney Flashing – This is a waterproofing material that your contractor will install at the intersection that connects the roof to the chimney. This flashing works to stop moisture from penetrating into the house through the roof.
  • Dormer Flashing – You use this part of the roof to add more protection against water damage. The contractor will install it under the sides and on top of your roof’s steel. You can also find it at the end wall or the dormer’s bottom.
  • Skylight Flashing – This is another waterproofing fixture that you’ll apply between the skylight’s frame and the glass. You apply this flashing right over your skylight sealants to help contain the moisture on the glass’s surface.
  • Valley Flashing – As the name suggests, you install this part of the roof in the roof’s valley line. It works as a waterproofing layer for your roof.
  • Vent Pipe Flashing – The final type of flashing gets externally installed on your home’s roof. It works like a sealant for your vent pipe, and it prevents water from seeping through any surrounding openings where it would normally slip through.

8 Flashing
Early Evening at Barkwell’s Cottage by Bill Barber / CC BY-NC 2.0

8. Rake

The rake is one of several roof sections on your parts of a roof. However, you won’t find this part exactly on your roof. Instead, the rake refers to the sloped sides at the ends on a gabled roof. The rake can overhang, or it can be a flat structure. You can leave a rake with overhangs open, or you can close them using fascia or soffit. The nice thing about the rake is that it’s easy to customize based on your chosen aesthetics. When done correctly, it will blend perfectly with your style while providing a layer or protection for the roof.

9 Rake
Reifel Residence (1922) 1451 Angus Drive by Heritage Vancouver Society / CC BY-NC 2.0

9. Hip

The hip is the external angle, and it functions as the intersection where adjacent sides of your roof that slope meet. You may know of an associated term called the hip end, and this refers to the triangular sloping surface that gets formed by the intersecting hips on your roof’s eaves or edges. You’ll find this part of a roof on a hipped roof design, and this design is well-known for its inward slopes and slants on all of the sides of the roof. Hipped roofs are very common in windy or snowy planting zones because it encourages the ice to slide easily off from the roof’s slants.

10 Hip
21a Minton House by Kansas Sebastian / CC BY-NC-ND 2.0

10. Dormer

You may hear this part of the roof referred to as the dormer window because it gives you a space to house your skylight. This part projects outward from the roof’s surface or past the plant of any pitched roof. Dormers also work to increase how much usable area you have in lofts or compact rooms. For example, maybe you want to convert your attic to an additional room. If so, adding a dormer or two is a great way to increase your ventilation, provide more natural lighting, and allow for better airflow overall without taking away from the floor space.

11 Dormer
Dormers by Marcy Leigh / CC BY-NC-ND 2.0

11. Drip Edge

A drip edge is a metal flashing type that works to protect your underlying roof features. You install it along your roof’s eaves to help encourage the water to flow away from your home’s fascia. If you look at the roof’s structure, this is the part that hangs from the roof’s sides. You’ll see a small metal flange that bends away from the roof’s fascia. Some people believe that this part of the roof isn’t essential to have anymore because you have your gutters to take on the bulk of the same job. However, this is still a functional feature.

12 Drip Edge
Drip edge and recycled plastics for edging by Juhan Sonin / CC BY 2.0

12. Fascia

When you talk about the fascia on your roof, you’re talking about a superficial itm on your roof that runs parallel to the ground. It gets positioned along the roof’s edges, and it gets fixed to the rafters. The fascia can work to support the gutters. Many people like for this part to be aesthetically-pleasing because this helps it contribute to the house’s facade and increase your property values. If you’re on a budget, it’s common to get rid of the idea of fancy fascia and go with a more budget-friendly choice. This means that you can get away with a simple wooden fascia, as long as you treat and paint or stain it to seal out the elements.

13 Fascia
Soffit and fascia by Jinx McCombs / CC BY-ND 2.0

13. Ridge Tile

The ridge on your roof eventually has a point where two different continuous sections of the roof will meet and come together. So, there is a gap at this point. The gap is the perfect spot for uncontrolled elements like animals or water to slip through and get into your home. To stop this from happening, adding a ridge tile is a common practice to prevent these unwanted things from getting in. You can make this part of the roof stand out by having it a different color from the roof itself, or you can make it blend in by using the same shingling or tiling as the rest of your roof has.

14 Ridge Tiles
Roof ridges and sun by Angelo Amboldi / CC BY-ND 2.0

14. Rafters

The rafters are the metal or wooden frames that function as your roof’s skeleton or frame. This is arguably one of the most important parts of the roof to concentrate on because there wouldn’t be any structure for your roof without them. This is a diagonal-shaped structure that gets included in your truss. The rafters meet in the apex, and the main function of this piece is to support the roof deck from any heavy loads. Generally, this is where you attach everything, so you want to further brace it to give it more support and strength as you work.

15 Rafters
Rafters by Drew Tarvin / CC BY 2.0

15. Underlayment

Also known as underlayment membranes, this part of the roof offers a protective cushioning or blanket for the entire roof decking. It helps to protect the roof by preventing too much moisture from building up. You’ll typically find them made out of rubber strips or felt, but they’re now also available in synthetic materials and reinforced fiberglass. They all work as waterproof materials that prevent moisture or water from building up on the roof decking. You’ll get different types depending on where you want to install it. The most common types of underlayment include:

  • Felt – This is a traditional type of underlayment that comes made out of felt paper. The main function is to waterproof the roof. You install it by stacking it above the solid decking board, and you cover it with shingles to seal it.
  • Rafter – The function of rafter underlayment is to give your rafters another layer of protection by adding a water-resistant layer on them to prevent moisture from getting through.
  • Synthetic – Just like the name suggests, this underlayment membrane features synthetic materials in the makeup. This is widely considered to be a high-tech type of underlayment that you install before you install the shingles. You’ll apply it in areas in the roof decking that don’t get covered by ice or water shields.
  • Valley – By definition, the roof valley is the part of the roof that channels a lot of water. This is why you need to apply a layer of valley underlayment. This is one waterproofing layer that works to add protection to the valley areas of your roof to prevent leaks.

16 Underlayment
Underlayment by H & S Roofing Charlotte NC / CC BY-NC 2.0

16. Water or Ice Shields

This part of the roof may not be 100% necessary, but you want to double-check because some states require you to have them installed by law to meet building codes and avoid fines. The shields are a specific type of underlayment that works to prevent wind-driven, heavy rains and ice dams from forming on the roof. You install them on three specific parts of your roof, including in the rakes and eaves to protect the roof’s interior from frost damage, in the roof valleys where water runoff could pool, and in the chimneys and flashings to let any wind-driven rains that get in to go back up.

17 Water or Ice Shields
A Seaview Beach Cottage (1895) by A.Davey / CC BY-NC-ND 2.0

17. Downspout

The downspout is a piece of pipe that connects directly to your gutter system. It runs vertically to the ground from the roof, and the biggest job of this part of the roof is to channel the rain water to a designated outflow point. You will usually purchase downspouts made out of galvanized steel or metal, but plastic ones are also available. This is an extremely important part of any properly functioning roof. If they malfunction, it can stop the whole gutter system from working. In turn, you can have water pouring directly down the walls, pooling around the foundation, and causing massive damage very quickly.

18 Downspout
Downspout by Timothy Allen / CC BY-SA 2.0

18. Skylight

This isn’t a 100% necessary part of a roof, and it’s widely considered to be a luxury feature you can see on some buildings or homes. It’s a window in the roof to put it simply, and installing one of these can be a very complicated process. This is somewhat risky to have too because a skylight is more prone to leaking. However, it’s a great feature to add if you want to allow for more light to enter the house. If you are considering adding one to your current roof, make sure that you pay close attention to the insulation and sealing so it doesn’t leak down the line.

19 Skylight
Skylight by Thomas Qhine / CC BY 2.0

19. Insulation

Your roof’s insulation is another critical component to consider. Most people realize that a building or house has insulation, but many people forget about roof insulation. You want to insulate the roof just like you would the walls. If a roof doesn’t have good insulation, heat will rise and escape right out of the roof, disappear, and your home will be cold. If you go into your attic and look at the roof’s interior, you may be able to see the insulation. It usually looks like cotton, or it can be a thicker spongy material. However, you shouldn’t tamper with it because this can compromise it. In turn, this can lead to higher energy bills and bad climate control.

20 Insulation
Deckhead insulation by Tim Zim / CC BY-NC 2.0

20. Splash Block

Your splash block is a facing that you put on your roof to help guard against gutter overflow when it pours. Usually, you’ll find it made out of galvanized metal or plastic to help prevent it from cracking in cold conditions or rusting due to element exposure. It’s almost as important a part of your roof as your gutters because the main job is to prevent the gutters from overflowing and seeping back into the edges of the roof. If it does, you can have problems with roof rot, insulation, and leaks.

21 Splash Block
The view from my balcony this morning by Eyesplash – Summer was a blast, for 6 million view / CC BY-NC-ND 2.0

21. Battens or Lath

The lath or battens come made out of metal or wooden strips. Their main function is to hold the shingles or tiles in place by helping secure them. It’s essential that you have the correct spacing in place for your battens because it’s the only way to securely install your tiles and shingles. You will install your battens horizontally, and the spacing will vary, depending on the type of roof you have.

22 Battens
Putting up the battens by Julian Berry / CC BY-SA 2.0

22. Solid Decking

Solid decking is more popularly called roof decking. This part of the roof is a composite decking made out of solid materials, as the name suggests. The decking mimics real wood, but it’s actually far sturdier to help support the bigger roof load to help keep it stable. It also adds another protection barrier between the home and the roof, and it gives additional surface for underlayment and shingles to make them more weatherproof. Structurally, this part of the roof features flat boards that get attached directly to the tusses, and they get stretched on joists across your room to make them sturdy.

23 Decking
Decking by Jake Johnson / CC BY-NC-ND 2.0

23. Abutment

This is a term that came about in the roofing and bridge construction industries, so it’s typical to hear it when you talk about parts of the roof. When you build a roof system, this term refers to the spaces in the roof where the slope of the roof intersects to a vertical spot like walls or the chimney. You can find them on the top, side, or around any of these vertical areas where they connect.

24 Abutment
Porto by PVersaci (1522) by Pascal VERSACI / CC BY-ND 2.0

24. Ceiling Joists

A large majority of the time, your ceiling joists will be made out of planks of wood. If you look, you’ll see the ceiling joists running along your roof’s rafters. The goal of having these joists is to help improve how strong the rafters are. They also work to support the soffits like a balcony, arch, or eaves.

25 Joists
Ceiling Joists by Thomas Quine / CC BY 2.0

How to Maintain Your Roof

Since it can be incredibly expensive to maintain your roof, you want to take steps to maintain it. There are several things that you can do to accomplish this, and we’ve listed out a few more common ones below.

  1. Clean the Gutter System

No one likes the thought of digging through sticks, decaying leaves, and general mush in the gutters, but you should take on this project once or twice a year. The goal is to ensure that water can flow freely out of your gutters into your designated area, and they can’t do this if they’re clogged. Leaving your gutters clogged will result in water backup, and it can run down the sides of your home to cause damage to the roof, walls, and foundation.

2. Inspect the Shingles

Make a point to do yearly shingle checks, especially after windier months or after you have a particularly bad storm. You should also note that it’s not just wind or bad weather that can damage your shingles. Ultraviolet light can also cause damage and weaken the shingles over time. When you look for damage, look for loose or broken shingles, lighter areas, or areas where the shingles are completely gone. If you notice any damage, you want to repair it quickly.

3. Ventilate and Insulate

Any roof that you comprehensively and properly ventilate and insulate will be less likely to have problems with moisture, and this reduces the chances of mold or rot. You should have your attic inspected to ensure that you have the correct insulation and the right amount. Ventilation is important too to prevent the attic area from “sweating” and causing issues. Warm air will rise and hit the cold interior wood layer to create condensation. Eventually, this can lead to mold growth and rotting wood. The vents should allow for proper air circulation, and it can also prevent ice dams.

Bottom Line

These 24 parts to your roof and the quick tips we gave you can help you get a better understanding of your roof as a whole. In turn, you’ll be able to keep it in good shape for much longer, and this reduces your costs while keeping your whole house in top shape.

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