Top 6 Roofing Materials for Seattle Area Homes Compared

How do the six roofing materials compare on lifespan, weight and price?

The table puts the six side by side. Lifespans come from InterNACHI's Standard Estimated Life Expectancy Chart for Homes (read October 2026). The chart says its figures should be used as guidelines only. Installed weights come from the Weight of Roofing Materials table by Jack Gray, RRO (updated December 2025), which takes most of them from manufacturer data sheets. Minimum slopes are from Chapter 9 of the 2021 Seattle Residential Code. Prices are for a typical 20 to 30 square roof from our October 2026 pricing guide. For the roofing we take on, see Roofing Contractors Across the Greater Seattle Area.

Our guide prices only shingle and standing seam metal.

Sources: InterNACHI life expectancy chart, read October 2026; Roof Observations, Weight of Roofing Materials, updated December 2025; 2021 Seattle Residential Code, Chapter 9; our roof replacement pricing guide, October 2026. Starting prices.

What does an asphalt shingle roof cost, and how long does it last?

An architectural asphalt shingle roof starts at $25,000+ for a small roof of 15 to 20 squares, $35,000+ for 20 to 30 squares and $50,000+ for 30 to 40+ squares. A square is 100 sq ft of roof. Designer or impact rated shingles start at $35,000+ for a small roof, $48,000+ for a medium roof and $68,000+ for a large one. Those are our October 2026 starting prices, and our guide recommends architectural shingle for most Seattle area houses.

InterNACHI's chart gives architectural shingles about 30 years and 3-tab shingles about 20 (InterNACHI, read October 2026). An architectural shingle weighs about 3.05 lb per sq ft installed (Roof Observations, 2025).

Shingles need slope. Section R905.2.2 of the 2021 Seattle Residential Code says: "Asphalt shingles shall be used only on roof slopes of 2 units vertical in 12 units horizontal (17-percent slope) or greater." From 2 in 12 up to 4 in 12, it requires a double layer of underlayment. Our Auburn carport, built in 2024, has an asphalt shingle gable roof over open wood trusses and sheathing.

Is a standing seam metal roof worth the price in the Seattle area?

Standing seam metal costs about twice as much as shingles and lasts about twice as long. Our pricing guide starts it at $50,000+ for a small roof, $65,000+ for 20 to 30 squares and $95,000+ for a large roof. That is about 1.9 to 2 times the architectural shingle price for the same size. The guide adds that metal sheds moss and rain well in the Northwest. Our Luxury tier uses concealed fasteners, custom bent trim and high temperature underlayment.

InterNACHI's chart lists metal at 40 to 80 years (InterNACHI, read October 2026). A 24-gauge steel standing seam panel weighs about 1.49 lb per sq ft, half an architectural shingle (Roof Observations, 2025).

Metal also goes where shingles cannot. Section R905.10.2 sets the minimum slope for standing seam roof systems at 1/4 unit in 12. Lapped metal panels without sealant need 3 in 12. On site, a small metal roof takes 1 to 2 weeks against 2 to 4 days for shingles.

How long does a cedar shake roof last, and how much does it weigh wet?

InterNACHI's chart lists wood roofing at 25 years (InterNACHI, read October 2026). Cedar also gains weight in the rain. Western red cedar 18 inch medium shakes weigh about 4.0 lb per sq ft dry and 6.4 lb wet, per the BC Shake and Shingle Association figures in the Roof Observations table (2025). The framing has to carry whatever goes on it, wet or dry.

Shakes need a steeper roof than shingles. Section R905.8.2 says: "Wood shakes shall only be used on slopes of 3 units vertical in 12 units horizontal (25-percent slope) or greater." Wood shingles have the same 3 in 12 minimum (R905.7.2).

Going over old shakes has its own rule. Metal and tile may go over an existing wood shake roof (R908.3.1 item 3), but where the new layer creates a combustible concealed space, Section R908.4 requires the whole old surface to be covered with gypsum board, mineral fiber, glass fiber or another approved material. Our pricing guide has no cedar price.

Can your house carry a clay or concrete tile roof?

Only if the framing is sized for it: clay tile weighs 6 to 15 lb per sq ft installed and concrete tile 6 to 11 lb, per the Roof Observations table (2025). That is 2 to 5 times an architectural shingle at 3.05 lb. A roof framed for shingles was not sized for that load, so a switch to tile starts with the framing. In Seattle, adding strength to rafters or trusses is a structural change, and Section R105.2 item 12 says "Permits are required for structural changes".

In return, InterNACHI's chart gives clay and concrete tile 100+ years (InterNACHI, read October 2026).

Section R905.3.2 says clay and concrete tile "shall be installed on roof slopes of 2-1/2 units vertical in 12 units horizontal (25-percent slope) or greater", with double underlayment up to 4 in 12. Tile cannot be covered later: Section R908.3.1.1 bans a recover where the existing roof is "slate, clay, cement or asbestos-cement tile".

Slate or synthetic slate: which lasts longer and weighs less?

Real slate lasts far longer. InterNACHI's chart gives slate 60 to 150 years and simulated slate 10 to 35 (InterNACHI, read October 2026). The old version of this post called synthetic the longest lasting; that chart does not support it.

Synthetic slate weighs less. A standard 3/16 inch slate roof weighs about 7 lb per sq ft, and an engineered polymer shake, slate or tile about 3.11 lb (Roof Observations, 2025). The synthetic figure is close to an architectural shingle at 3.05 lb.

Slate also needs a steep roof. Section R905.6.2 of the 2021 Seattle Residential Code says: "Slate shingles shall be used only on slopes of 4 units vertical in 12 units horizontal (33-percent slope) or greater." Like tile, an old slate roof cannot take a recover (R908.3.1.1).

What roofing goes on a flat or low slope roof?

Below 2 in 12, shingles are out. Membranes and standing seam metal both go down to 1/4 in 12. The 2021 Seattle Residential Code sets a design slope of at least 1/4 unit in 12 for modified bitumen (R905.11.1), thermoset single ply such as EPDM (R905.12.1) and thermoplastic single ply such as TPO (R905.13.1).

Single ply membranes are the lightest coverings in the table. TPO also has the shortest life in it, 7 to 20 years. A fully adhered 60 mil TPO weighs about 0.29 lb per sq ft and a 2 ply modified bitumen about 2.0 lb, membrane only (Roof Observations, 2025). InterNACHI's chart gives TPO 7 to 20 years, EPDM 15 to 25 and modified bitumen 20 (InterNACHI, read October 2026).

Another answer is to add pitch. In Auburn in 2024 we replaced a flat carport roofed with translucent corrugated panels with a gable roof in asphalt shingles. The whole carport cost about $75,000. How to Build a Carport: What You Should Expect covers that kind of build, and Home Remodeling Contractors in Auburn, WA covers other work in that city.

Does switching to a heavier roofing material need a permit in Seattle?

Yes, when the framing has to change. Section R105.2 of the 2021 Seattle Residential Code (PDF page 1-7) lists work exempt from permit. Item 12 is "Roof replacement if no changes are made to the building envelope other than adding or replacing insulation, and the work is equivalent to or better than the existing structure." The same item says "Permits are required for structural changes and replacement of sheathing of any size." A move from shingles to tile or slate that needs stronger rafters is a structural change. We file the permit when the job replaces sheathing or changes the structure.

This post compares materials only. For the replacement steps, read 7 Tips for Replacing Your Roof in the Seattle Area. For pitch, underlayment, ventilation and flashing, read Roof Construction: Top 7 Factors to Consider.