When looking to get your roof replaced, you’re going to have to get bids from different roofing contractors. Depending on the level of detail in those bids, you may notice some terms you’re not familiar with. What is drip edge metal? Underlayments? Or Starter shingles?
Unfortunately buying a new roof is not as simple as picking out a brand, color or type of asphalt shingle. While the main roofing material itself does get all the attention, there are many other parts of an asphalt roof that are less obvious. However, these smaller components play a very important role in keeping the water out of your home. And if you buy the fanciest asphalt shingle available on the market, but your contractor installs it with cheap components, your roof may leak soon after it’s installed!
This guide will walk you through the different parts of an asphalt roof – the material components that you don’t really get to see. We’ll check out each one and explain what it’s purpose is, and what kind of quality of material you’ll need to keep your home secure and watertight for decades to come. Depending on where you live can make a difference in materials you need on your roof. This guide is meant for those in North Idaho and Spokane and all the information is for up here where we get a great deal of snow.
Asphalt Shingle
There are many different types of asphalt shingles, but they are all similar. They start with a fiberglass mat that gives them strength. This fiberglass is then coated in asphalt to make it waterproof. Then the asphalt is covered in ceramic granules to protect the asphalt from the sun. While it’s not quite that simple, this is basically how asphalt shingles are put together. They are by far the cheapest and most common type of roofing material out on the market.
Asphalt shingles are a great choice for a new roof, especially if you haven’t been saving up for this to happen. But in order for an asphalt shingle roof to be watertight and last for decades to come, it has to be installed along with quality components.
What is Fascia Board?
The fascia board on your home is a long, straight piece of material—usually wood, vinyl, or aluminum—attached to the lower edge of a home’s roof. It runs along the roofline, connecting to the ends of the roof rafters or trusses, and serves both practical and aesthetic purposes.
Practically, it supports the bottom row of shingles and provides a mounting point for gutters, helping direct water away from the house. Aesthetically, it gives the roof edge a finished, clean look by covering the exposed ends of the rafters. On a home in North Idaho, where heavy snow and rain are common, a sturdy fascia board is key to protecting the roof structure from moisture damage.
Fascia board is usually not seen as “part” of the roof, but if it is starting to rot out or is damaged in any way, the time to replace it is when you replace your roof. If it’s damaged that points to an existing roof problem as well that will need to be addressed when it’s replaced.
What is Drip Edge Metal?
Drip metal or drip edge is a metal flashing, usually 10’ long, that is installed around the perimeter of your roof. Its main job is to protect the fascia board from water damage. It is installed to the roof surface, and hangs over the fascia board to protect it.
We recommend a ‘D’ style drip metal that covers 2” on the roof surface and extends out, back, and down the fascia to keep water off the fascia. You can still buy a 1 ½” ‘G’ style metal, that is basically an ‘L’ that doesn’t have the kick out. This metal is cheap, but according to the latest code requirements it is no longer legal. Drip metal must extend up the roof a minimum of 2”.
What to watch out for on your roofing bid:
- 1 ½” ‘G’ style metal being used
- Only installing it on the eaves (the bottom edge) of your roof, and not the rakes (the sides).
What are Underlayments?
Underlayments are back-up protection and are installed directly over the plywood or OSB roof decking. This layer protects your home from weather while the roof is being installed and will continue to protect from extreme weather events (like ice dams) or in the case a shingle blows off during a storm.
What is Ice & water shield?
Ice & water shield is very important here in North Idaho & Spokane, as it can protect your home from water intrusion in the case of ice damming. Ice dams happen when the heat from your home melts the snow on your roof, and the water runs down to the eaves and refreezes. This builds up and can trap water on your roof, which can then find it’s way into your home. A quality ice shield installed in the correct spots is an important step to prevent water from getting in your home during one of these years.
Ice & water shield is installed along the eaves of your home, in the valleys, up against all walls, and around all flashings. According to code, it must extend from the edge of the roof up to 24” inside the exterior wall. This is where ice dams occur so if it’s not installed up far enough it won’t protect you where you need it most. It also needs to be installed over top of any drip metal on the eaves (bottom edges) of the roof, and under drip metal on the rakes (side edges)
There are multiple qualities of ice & water shield on the market, with very cheap products coming in at around ½ the cost of a quality product. This is not an area you want to skimp. The best ice shield is one that has a synthetic top that will prevent ripping during the installation of your roof, as well as a thick, adhesive layer that will stick to your plywood and form a layer of waterproof protection.
What to watch out for on your roofing bid:
- Cheap ice shield with a thin adhesive layer and a granulated surface
- Not installing enough of it – either high enough up the roof, not in valleys, or around flashings.
- Installing drip metal over top of the ice shield on the eaves (bottom edges) of the roof.
What is Synthetic Underlayment?
Synthetic underlayments will cover the rest of the roof – anywhere ice & water shield is not needed. This is about 25% of the cost of ice shield, so it makes sense to use it wherever possible. This must be installed with cap nails or staples, which divert water away from the fastener to keep it water tight. If it’s installed with normal tacker staples it will leak.
There are cheap builder grade qualities of underlayment that are not recommended, but it can be hard to tell the difference by looking at it. Ask your contractor for a sample of it so you can feel how tough it is. Another product available is the old ‘tar paper’ – this is not widely used anymore since it has the tendency to wrinkle and tear easily.
What to watch out for on your roofing bid:
- Organic felt paper
- Cheapest builder grade materials being used
- Installed with regular tacker staplesstapes (you should see 1” diameter orange or green circles all over it)
What Are Starter Shingles?
Starter shingles are installed along all the edges of the roof and provide an additional adhesive strip to help secure the first row of regular shingles. On the eaves they help to offset the seams of the first layer of shingles so water doesn’t run under your drip metal (and in your house). They guard against wind uplift at the roof’s edge and create a neater, more uniform look.
These should be installed around the entire perimeter of the roof, before the primary shingles, to give the most wind resistance and warranty available.
What to watch out for on your roofing bid:
- Only installing starter shingles on the eaves of the home.
- Not offsetting the seams on the bottom row of shingles.
What is Hip & Ridge Cap?
Specialized hip & ridge cap is made to cover the intersection of any 2 roof planes. This can be at the top of the roof (ridge) or the triangle sides of a roof (hip). Ridge cap should always be installed with longer nails so they reach down through the layers of shingle and into the plywood securely.
If it’s installed over a ridge vent, then it will need even longer nails (2 ½”) and will usually need to be hand nailed. If this isn’t done the nails will not reach through the plywood, and blow-offs are likely to occur.
What to watch out for on your roofing bid:
- Cutting shingles to use for ridge cap – it’s not made for this and bending the shingle will cause it to fail early.
- Installing with nails that are too short, especially over ridge vent
What is Valley Metal?
Valleys are the area on the roof where 2 roof slopes meet, where all the water will gather and run down. Valley metal is a flashing that lines the valleys to protect them from water intrusion and strengthens this vulnerable area.
On some asphalt shingle roofs and all metal roofs, this is exposed in the middle of the valley, and the edges are covered by the roofing material. It is usually 24” wide, and has a peak in the middle that divides each side (called ‘W’ valley metal). These must be fastened well away from the valleys, any fasteners put a hole in the metal where water can get into.
On lighter weight asphalt shingle roofs this is usually hidden under the shingles. It works to prevent ‘step throughs’ that can occur when someone steps in a valley and breaks the shingle, causing water to pour into the home. It’s technically not required by code if ice shield is present, but it is highly recommended.
What to watch out for on your roofing bid:
- Fasteners being installed too close to the center.
- Not installing valley metal at all.
What are Wall Flashings?
Wall flashings are installed to protect the intersection where the horizontal roof surface meets a vertical wall. These are one of the most common leak spots in a roof so extra care must be taken to get these right.
A step that can save an installer a ton of time and some materials is to re-use the existing flashing. This is fairly common in our area, and can lead to your roof leaking shortly after it’s installed. All those old flashings have nail holes in them, and if they are reused, one of the most critical components of your roof is already worn out. In order for your roof to last a lifetime, all new flashings must be installed.
What is Step Flashing or Side Wall Flashing?
On an asphalt shingle roof, we install step flashing (sometimes called side wall flashing) up a sloped wall. These must be installed 1 per shingle and nailed as far away from the joint as possible to prevent water intrusion. This will ensure any water that runs down your siding and along this intersection will hit the flashing and run off your roof instead of into your home.
What is Roof-to-Wall or End Wall Flashing?
Where the roof slope goes up and meets a vertical wall at the top, we use a flashing called roof-to-wall or end wall flashing. It’s kind of like a cap for roof surfaces that go up and hit a wall. Water will run down the siding, onto this flashing, then onto the shingle below.
It’s common for roofers to just nail these and caulk the nails, which doesn’t look that great and will leak once the caulking wears out. Or worse, they cover them with shingles – this will allow water to run under those shingles and straight into the nail holes. The correct way to fasten these flashings is with a metal roof screw with a rubber grommet to prevent water intrusion.
What to watch out for on your roofing bid:
- Step flashings being installed 1 for every 2 shingles.
- Exposed nails or shingles used to fasten roof-to-wall flashing.
- Reusing the existing flashing.
What are Pipe Flashings?
Every roof has pipes that come up through the roof surface. These are also called “penetrations” because it’s basically a hole in an otherwise flat area of roof. These are another one of the most common areas that a roof will leak not long after it’s installed.
These come in a range of qualities, ranging from plastic and rubber at about $5, to metal and thick silicone for $100 or more depending on the application. While the plastic ones are cheap and commonly used, plastic and rubber deteriorate quickly in the sun, and these can crack and leak after just a few years of sun exposure.
The next step up is a metal base with a rubber boot, but the rubber is the point of failure on these. We’ve fixed many roof leaks on relatively new roofs because this boot had broken down and cracked and was letting water into their living room.
The best kind you can get has a metal base with a thick silicone boot. Silicone is resistant to the sun and will last the lifetime of the roof. Though it costs a lot more comparatively, this is not a huge cost when it comes to the whole roof, and can save a lot of headaches in the future.
All pipe flashings have a very small base, so it’s best to extend the edges out with a high quality ice shield to double protect these vulnerable areas.
What to watch out for on your roofing bid:
- Cheap plastic or metal flashings with a rubber boot.
- Not installing with ice shield to extend the small metal base.
What is Roof Ventilation?
Roof ventilation is maybe the most critical part of a new roof that gets overlooked the most. Poor attic ventilation does not let the attic breathe to let heat and moisture escape, which can cause
- Condensation build up in your attic, which can lead to mold/mildew growth and dry rot.
- A hotter home and higher cooling bills in the summer.
- Severe ice dams and water intrusion in the winter.
A proper attic ventilation system needs two things to be efficient: intake and exhaust ventilation.
Exhaust ventilation is installed at the top of the roof. This allows the hot moist air in the attic to escape. If there is not enough exhaust ventilation, then the warm, moist air will get trapped and start to condensate on the plywood and trusses, which can lead to mold and fungus growth, wood rot, and even insect infestations.
Intake ventilation is installed at the bottom edges of your roof, usually in your soffits. As the heat rises and escapes out the exhaust ventilation, this draws fresh outside air into the attic at the bottom of the roof. If the intake ventilation is clogged (usually by insulation) then fresh air won’t get drawn in and it will make your exhaust ventilation almost useless.
When these 2 systems are working together they form a cycling system that will allow your attic to “breathe.”
What Are Roof Louvers or Can Vents?
These are installed by cutting 8”x8” holes near the top of your roof, and installing roof louvers just below the ridge cap. Most roofs will need multiple vents added to meet code requirements, which can be hard to fit in and make look symmetrical. Installing roof louvers on your home will do a fine job as long as there is enough to meet or exceed code requirements.
Roof vents, like pipe flashings, come in both metal and plastic varieties. Plastic roof vents are cheaper but will bake in the sun and crack, letting rain fall right into your attic. While metal vents are about twice the cost, it’s well worth it. These also have a small base and should be installed with ice & water shield to extend the metal base.
What to watch out for on your roofing bid:
- No ice shield installed around the metal base
- Plastic vents being used that will crack in the sun.
What is Ridge Vent?
Ridge vent is a continuous vent that is installed by cutting a 2” gap in the plywood at the very peak of the roof. This is very sleek and blends right in with the roof, removing the need for the unsightly roof louvers. A big benefit of ridge vent is that it will usually double the amount of ventilation required by code, and can work wonders to keep your home cooler in the summer and prevent ice dams in the winter.
The best ridge vent has an external baffle that will prevent the wind from blowing through the vent and negating it’s ability to vent properly. It will also need caps at the end of the roof to prevent pests like bugs and bats from nesting inside your attic.
Pretty much all ridge vent is made from some type of plastic. This is OK, because it is installed with a layer of ridge cap over the top that protects it from breaking down in the sun. However, this ridge cap must be installed with longer nails (2 ½”) that reach down into the plywood, or it will be vulnerable to be blown off in a future wind storm.
What to watch out for on your roofing bid:
- Installing it without cutting a hole in the ridge or leaving it covered (plugged) by underlayment. (Yes, we’ve seen this plenty of times)
- Installing with nails that are too short.
- Ridge vent with no external baffle.
- Leaving the ends open allowing pests in
What are Skylights?
Skylights are a desirable feature to have in your roof and are becoming more and more common. They let in natural light and can brighten up rooms a lot without introducing new electrical lighting. Depending on the type you’re looking for, you can even get solar powered skylights that open and close to let fresh air into your home. There are 2 main types of skylights.
What are Traditional “Window” Skylights?
This type is what t comes to mind for most people when they hear “skylight.” They are basically a window in your roof that you can see through, the most common size is 2’ x 4’. They provide great natural light and can be almost any size you want. Plus, there are options that allow you to open & close (manually or electronically) and can be hooked into existing electrical systems or solar powered.
When you replace your roof, it’s usually a good time to replace the glass of your skylight as well. Just like your exterior windows, the glass of skylights has a gas in them that insulates to prevent too much heat transfer through them. Over time this wears out and your skylight will leak heat in the winter (or let the summer heat in), so replacing it with your roof can help decrease your heating & cooling costs.
Whether or not you replace the window itself, it’s critical that all new flashings are installed when you replace the roof. The existing flashings already have holes in them from the previous installation, so reusing them is not an option. A lot of times there are ‘flashing kits’ that can be purchased to custom fit these skylights, but custom flashing can be created as well.
What to watch out for on your roofing bid:
- Reusing the old glass when reroofing.
- Not installing new flashing around the skylight base.
What are Sun Tunnels?
Sun tunnels are a great feature that provides natural light without the huge costs of adding a skylight. They are composed of a small ‘dome’ on the roof that catches the sun, which is connected to a tunnel with a mirrored inside surface that goes through your attic. Then inside the home a circular light is installed that looks like a low profile LED light. This let’s light travel through your attic and light up a room in your home. These work great, and are especially good for lighting up interior rooms that don’t have windows.
When installing a new roof on your home, the top portion of the sun tunnel should be replaced. The ‘domes’ on the roof are usually a thick plastic which will wear out over time. These will also discolor in the sun over time which can reduce the amount of light that gets through into your home. Like everything you put on the roof, try to get one with a metal base.
What to watch out for on your roofing bid:
- Reusing the existing flashing and ‘dome’
- Using a dome with a plastic base.
What are Chimneys?
Chimneys are by far one of the most leak prone areas in a home. There are many things that can go wrong on a chimney and let water into your home. Not only do they have flashing that ties them into the roof and is a vulnerable area, but the top and sides of the chimney can also let water in if they are deteriorating.
When you get your roof replaced, it’s a great time to address any potential issues with the chimney. All the roof flashings will definitely need to be replaced, this is a given. However you may find that you need new counter-flashing as well (the flashing that is connected to the chimney and covers the roof flashings), and maybe even seal up some deteriorated spots on the sides or top. Depending on the type of chimney you have will determine the type of maintenance needed.
What to watch out for on your roofing bid:
- Reusing existing flashings around the chimney.
- Not addressing the other issues your chimney could have.
What are Gutters?
Almost every new house built these days has gutters installed on it. They play a critical role in diverting the large amount of water that runs off your roof away from the homes foundation and off the landscaping. Without gutters, all the dripping from your roof can cause pits in your concrete, holes in the grass, and your flower beds to splash dirt all over your home. Worse, all that water can seep back towards your home and start to leak into your foundation.
We recommend all homes have gutters along the eaves to catch the water and divert it to where it won’t cause a problem. If you don’t yet have gutters, adding them will increase the longevity of your home and prevent other potential issues.
If you already have gutters, check their condition (or ask your roofer to!) to determine if you should replace them when you do the roof. If you notice that the joints on your existing gutters are leaking, or the water does not flow out of them properly, replacing them is a good option. While you can get a ‘tune up’ that will reseal the joints and make them last for a few more years, it’s impossible to fully seal the joints because of the years of dirt and grime coating the inside of the gutter.
For most homes, 5” K-style seamless aluminum gutters are ideal (and the most common). They come pre-painted with a durable coating and since they are aluminum they won’t rust. There are other fancier options too, such as copper and different styles that require specialized molds to create.
What to watch out for on your roofing bid:
- Replacing your gutters with plastic or metal that aren’t seamless (very leak prone).
- Removing existing gutters w/ no option for new ones.
- Existing gutters being damaged by the roof removal.
Building a Roof That Lasts in North Idaho & Spokane
I know this is a lot of information, but replacing your roof is a big investment, and understanding the components beyond the shingles—like fascia boards, drip edge metal, underlayments, and flashings—can make all the difference in getting a watertight, long-lasting result. In North Idaho and Spokane, where heavy snow, ice dams, and relentless rain test every roof, skimping on these critical pieces is like rebuilding a car engine without replacing the gaskets—sooner or later, the leaks will show up. A detailed roofing bid might seem overwhelming at first, but now you’re equipped to spot the red flags: cheap materials, skipped steps, or reused parts that could leave your home vulnerable.
When you choose a contractor, look for one who prioritizes quality across every layer of your asphalt roof, from the ice and water shield guarding against our brutal winters to the valley metal reinforcing those high-water runoff zones. A roof isn’t just about curb appeal—it’s about protecting your home for decades. So, take this knowledge, review those bids with confidence, and ensure your next roof stands up to the toughest North Idaho weather Mother Nature can throw at it.