Replacing a roof in the Dayton area

How long a roof lasts in the Dayton area

Our weather wears roofs down gradually. The Miami Valley sees many freeze-thaw cycles in winter, humid summers and spring storms that bring wind and sometimes hail. Each of these breaks down shingles, flashing and sealant a little at a time.

Standard three-tab asphalt shingles often last somewhere around 15 to 20 years here. Architectural (dimensional) shingles are thicker and often last longer. Metal roofing can outlast both by a wide margin. These are rough ranges, not promises. Some roofs wear out early:

• a roof with poor ventilation
• a south-facing slope that bakes all summer
• a roof under heavy tree cover that holds moisture

A well-vented roof on an open lot can outlast its expected range.

Treat age as a reason to look closely, not as a deadline. If your roof is getting older, have it inspected and read through the signs you need a new roof.

Shingle types and other roofing materials

Most homes around Dayton have asphalt shingles. You will hear about three kinds:

• Three-tab shingles are flat, single-layer and uniform. They cost less up front and are less common on new installs than they used to be.
• Architectural shingles are made from two or more laminated layers. That gives them a textured, shadowed look and better wind resistance. Most reroofs use them today.
• Premium or designer shingles are heavier still and are made to look like slate or wood shake.

Asphalt is not the only option:

• Metal roofing, standing seam or exposed-fastener, works on houses and outbuildings.
• Slate is still on some older homes in established neighborhoods. Repairing or replacing it is a specialty job.
• Membrane systems are needed on very low-slope sections like some porch roofs and additions, because shingles are the wrong material there.

The comparison of asphalt shingles and metal roofing goes into more detail.

What goes under the shingles

Shingles shed most of the water. The layers underneath catch what gets past them.

Decking is the wood the roof is nailed to. Newer homes use plywood or OSB. Many older Dayton homes, especially those built before the mid-1900s, have board (plank) decking with gaps between the boards. A roofer may need to replace soft or rotted sections, or sheet over the planks, so the new shingles have a solid nailing surface. Nobody knows how much decking work is needed until the old roof is off. A good estimate explains how decking repairs will be handled.

Ice and water barrier is a self-adhered membrane. It goes along the eaves, in valleys and around chimneys and vents. In our climate it is the main defense against ice dams pushing water under shingles. Your local building department sets the minimum.

Underlayment covers the rest of the deck. Synthetic underlayment has largely replaced felt paper because it resists tearing and lies flatter.

Flashing and drip edge seal the joints where the roof meets walls, chimneys and edges. Reusing worn flashing is a common reason a new roof leaks.

Attic ventilation

An attic needs steady airflow. Outside air should come in low, through soffit or other intake vents. It should leave high, through a ridge vent or other exhaust vents. When that works, the attic stays close to the outside temperature. It stays cooler in summer, which spares the shingles, and cold and dry in winter, which limits ice dams and condensation.

Replacement is the best time to fix ventilation because the roof is open. A roofer should check three things:

• whether soffit vents are blocked by insulation or paint
• whether the exhaust matches the intake
• whether mixed vent types are working against each other

Bathroom and kitchen fans should vent outside, not into the attic. There is more detail in why attic ventilation matters.

Tear-off vs. overlay

An overlay means nailing new shingles over the existing layer. It is quicker and creates less debris. Building codes generally allow it only when there is one existing layer in sound condition.

A tear-off strips the roof down to the deck. It takes longer, but it lets a roofer:

• see and repair the decking
• install ice barrier and underlayment correctly
• replace flashing
• fix ventilation

It also avoids adding weight and hiding problems that will show up later. An overlay has drawbacks:

• it can trap moisture between layers
• the new shingles follow any unevenness in the roof below
• next time, there are two layers to remove

For most homes, a full tear-off is the better choice. If someone recommends an overlay, ask why. Ask what they will do about the flashing and the eaves.

What replacement day looks like

Before the crew arrives:

• Move cars out of the driveway and garage if the crew will be working above them.
• Take pictures and fragile items off the walls. Hammering shakes the house.
• Cover anything stored in the attic, because dust and debris will come through.
• Keep kids and pets inside or away from the work area.

On the day, the crew covers landscaping and siding with tarps and sets up a dumpster or trailer. They strip one section at a time so the house is never fully open. Once the deck is bare, they replace bad wood. Then they install drip edge, ice barrier, underlayment, flashing, shingles, and the ridge vent or caps.

Many homes take one to two days. Steep or complicated roofs take longer, and weather can interrupt the work. A careful crew does not tear off more than it can cover before rain.

Cleanup should include a magnetic sweep for nails across the yard and driveway. Before final payment, walk the property with the roofer and check the gutters, which collect granules and debris. If you are thinking about new gutters, it is practical to replace them along with the roof.

Choosing materials for your house

Start with the house, not the brochure.

• Pitch and shape. Low slopes and roofs with many valleys or dormers have fewer good options.
• The house and the street. Architectural shingles suit most homes. Metal works well on farmhouses, outbuildings and some modern homes. Some neighborhoods, homeowners associations and historic districts have rules about materials and colors, so check before you choose.
• Color. Lighter colors reflect more summer sun. Darker ones hide staining. Algae streaks are common on shaded north slopes here, and algae-resistant shingles help.
• How long you plan to stay. A longer-lasting material makes more sense if you will be in the house for decades.
• Wind and hail. If your house is exposed, ask about wind ratings and impact-resistant shingles.

Ask every roofer the same questions:

• What underlayment and ice barrier will you use, and where?
• How are decking repairs priced and approved?
• What happens to the existing flashing?
• How will you handle ventilation?

When every roofer answers the same questions, the bids are easier to compare.

Frequently asked questions

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