Roof Replacement: What Goes Into a Quality Installation

You've got two or three estimates sitting on your kitchen table and they're not the same number. Maybe one is $4,000 less than the others. Before you call the low bidder, it's worth understanding what you're actually comparing because a roof replacement isn't just shingles. It's a layered system, and the components under the shingles determine how the whole thing performs for the next 20 to 30 years.

Here's what a complete, quality installation looks like from the deck up.

The Decking

Everything starts here. Before a single piece of new material goes on, the existing decking gets inspected for soft spots, rot, and damaged sections. Decking is typically ⅝ inch or ½ inch OSB or plywood, and any section that has absorbed water or been damaged by a previous leak gets replaced before the new system goes down.

This is one of the places where bids diverge in ways that aren't visible on paper. Some contractors price decking replacement separately and quote it as an unknown until they're up there. Others don't bring it up at all and deal with it or don't on installation day. Ask any contractor you're considering how they handle decking replacement and whether it's included or billed as an add-on.

Ice and Water Shield

In the Midwest, ice dams are a real problem. When snow on a warm roof melts and refreezes at the cold eaves, water backs up under the shingles. Ice and water shield is a self-adhering membrane that goes down at the eaves, in valleys, and around penetrations to stop that water before it reaches the decking.

Landmark uses Owens Corning WeatherLock on these critical areas. It's a rubberized asphalt membrane that seals around the nail  so even if water gets under the shingles, it can't get through the membrane. The difference between a house with proper ice and water shield and one without shows up the first winter after a significant ice event.

Synthetic Underlayment

Underlayment is the layer between the decking and the shingles, a secondary barrier that protects the roof during installation and provides backup protection once the shingles are on. Felt paper (also called tar paper) has been the traditional underlayment for decades. It works, but it absorbs moisture, tears in wind, and degrades faster than the shingles above it.

Landmark installs Pro Armor Synthetic underlayment in place of felt. It's lighter, significantly more tear-resistant, and doesn't absorb water if the roof gets wet before shingles go down. On a multi-day installation or a job that gets caught by rain, that distinction matters. Synthetic underlayment also has a higher UV resistance rating if sections of the roof sit exposed for any length of time.

If a competitor's bid doesn't specify synthetic underlayment, it's likely priced with felt. That's a meaningful difference in what you're getting.

Drip Edge

A drip edge is a metal flashing that runs along the rake of the roof. Its job is to direct water away from the fascia rather than letting it run behind them and rot the wood beneath. It seems minor until you're replacing fascia boards.

Installation order matters here. At the eaves, the gutter apron goes down before the underlayment so water that gets under the shingles runs over it and out. Get it backwards and you've created a water trap.

Flashing

Flashing is the sheet metal work around every transition on the roof  chimneys, skylights, pipe boots, walls, and valleys. It's also one of the most common sources of leaks, because it's where the roofing system has to change direction or material and seal against something that moves independently of the roof.

Step flashing at a sidewall, for example, consists of individual L-shaped pieces of metal woven into each course of shingles as they go up, not a single continuous piece of metal caulked in place, which is the shortcut that fails. Chimney flashing involves both a base flashing embedded in the shingles and a counter flashing set into the mortar joints of the chimney itself. Done right, it handles the differential movement between the chimney and the roof deck. Done wrong, it leaks within a few years.

Any estimate that doesn't address flashing replacement or at least inspection and resealing is leaving out a critical piece of the job.

Shingles

This is the part most homeowners focus on, and it's the most visible line item on a bid. Shingle quality varies significantly. The main variables are warranty length, wind rating, and impact resistance class.

Landmark's warranty tiers are tied to the shingle product and the installation system. At the higher end, Owens Corning Duration shingles installed with the SafeLock fastening system, a six nail pattern with nails driven in the specified nailing zone qualify for enhanced wind warranties up to 130 mph. At the standard tier, properly installed architectural shingles carry a lifetime limited warranty on the material and a 10-year labor warranty through Landmark.

The fastening pattern matters more than most homeowners realize. A shingle nailed too high, too low, or with too few fasteners fails the wind warranty regardless of what the shingle itself is rated for. This is one reason the installation crew's experience is as important as the material spec.

Ridge Cap and Ventilation

Ridge cap shingles run along the peak of the roof and take more UV and weather exposure than any other part of the system. Purpose-made ridge cap shingles are thicker and more durable than cutting standard shingles into pieces for the ridge, which is the cheaper approach some crews use.

Underneath the ridge cap is typically a ridge vent, which is part of the attic ventilation system. Proper ventilation  intake at the soffits, exhaust at the ridge  keeps the attic from becoming a heat trap in summer and prevents moisture buildup in winter that leads to mold and premature shingle aging. A new roof installed over a poorly ventilated attic will age faster than the warranty assumes, and manufacturers can and do deny warranty claims when ventilation doesn't meet their specifications.

Comparing Bids With This in Mind

When you're looking at estimates side by side, the shingle brand and color are the easiest things to compare. The harder comparison is everything underneath whether the bid includes synthetic underlayment or felt, whether ice and water shield placement is specified, how flashing is being handled, and whether the fastening system qualifies for the wind warranty being quoted.

A lower bid often reflects one or more of those components being downgraded or left out. That's not always a dealbreaker, but it should be a conscious choice rather than a surprise after the crew has left.

If you have questions about what's included in a Landmark estimate or want to talk through what your specific roof needs, we're happy to walk you through it.

Learn more about our residential roof installations or explore financing options if budget is part of the conversation.

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