How to Get a Siding or Roof Replacement Estimate From Your Address in Vancouver, WA

You can get a starting price for a siding or roof replacement by entering your address. Aerial roof data gives the roof area in squares, the pitch of each roof plane and an estimate of the exterior wall area. The result is a price range. A contractor sets the final price after inspecting the house in person.

This guide is for homeowners in Vancouver and the rest of Clark County. It explains how the measurement works and what only an in-home inspection can find.

Measured Bid is estimating software for exterior contractors. Teams price jobs from an address in the dashboard, and homeowners get a price range from a widget on the contractor's website. Both use the contractor's own pricing. We wrote this as a guest post for GVX Remodeling. GVX does not use Measured Bid.

Can you get a siding or roof estimate from just your address?

Yes. There are two common ways to do it.

The first is a price tool on a contractor's website. Measured Bid's widget works this way. You type your address, confirm the house on an aerial image and answer a few questions. The tool measures the house and shows a price range built from that contractor's rates. When you send the form, the contractor gets your contact details with the measurements attached.

The second is a free measurement tool. Measured Bid's free roof measurement tool returns roof area, squares and the pitch of each roof plane. Its wall-area calculator for siding returns net wall area and siding squares for 1, 2 or 3 stories. Neither one shows a price. You can take the numbers to any contractor and compare them with the quantities on their estimate.

Either way, have these facts ready:

• The street address, and which building on the lot you want measured.
• The number of stories.
• The new material. For a roof that means asphalt shingle, metal or tile. For siding it means fiber cement, engineered wood or vinyl.
• What is on the house now. For a roof, include how many layers of shingles are on it.
• For siding, how much of the house gets new siding. That could be all walls, part of the house, or only the gables and accents.

How does address-based measurement work?

The house is measured from above. Measured Bid uses Google's aerial roof data, which maps roof planes for most US addresses. Each plane comes with its direction, its pitch and its sloped area. Walls are then worked out from the roof outline.

Roof area, pitch and roof planes

The sloped area already includes the pitch. The tool adds up the planes and divides by 100 to get squares. It also names the roof type: gable, hip, shed, low slope or complex.

Planes flatter than 2/12 are marked as low slope, because they need a different roofing system than shingles. The steepest plane is flagged when it is steeper than 8/12.

The result shows the year of the aerial imagery and a confidence level. It warns you when the imagery is 5 or more years old. It also flags a house when less than 90% of the roof is mapped.

Exterior wall area for siding

Walls are hard to see from straight above, so wall area is calculated from the roof outline. The siding calculator follows five steps:

1. Take the roof outline and subtract the overhang on each side. It starts at 18 inches. That gives the wall perimeter.
2. Multiply by the wall height. It starts at 9 feet per story.
3. On gable roofs, add the triangles above the end walls.
4. Subtract windows and doors as a share of the wall. It starts at 10% for siding.
5. Divide by 100 to get squares of siding.

A contractor can change each starting value. The calculator does not see individual windows, stone or brick sections, or walls that step down a slope. Those get measured at the house.

What is a roofing square?

Siding uses the same unit. A siding square is 100 square feet of wall.

Floor area and roof area are different numbers. Overhangs, garages, extra stories and pitch all change the roof area. If you only have a flat measurement of the roof outline, multiply it by the pitch factor in the table below.

The factor is the square root of 1 plus the pitch squared. For 6/12, that is the square root of 1.25, or 1.118. Use it only on a flat measurement. Sloped area from an aerial tool already includes the pitch.

How do contractors measure a roof for replacement?

A roofer prices a replacement on the sloped roof area. Then they adjust for the parts that take more material or more labor. Most estimates build up in this order:

• Squares. Sloped area divided by 100.
• Waste. Extra material for cuts at hips, valleys and starter courses. It depends on the roof shape.
• Steep sections. Steep planes are slower to work and need more safety gear. The adjustment should apply only to the steep planes, and it does not add roof area.
• Tear-off. Priced per square for each layer removed, on the measured squares without waste.
• Stories. A taller house takes more staging and more time.

Measured Bid starts each roof type with its own waste allowance, and each contractor can change it:

Two ways a roof estimate gets inflated by mistake

The first is applying a pitch factor to an area that already includes slope. The second is counting waste twice, once inside the material rate and again as its own line. Measured Bid's guide to estimating a roof replacement works through both with an example. If your estimate shows a pitch factor and a separate waste line, ask whether the rate already includes either one.

How do contractors measure a house for new siding?

Siding is priced on net wall area. That is the square footage of wall that will actually get new siding. Contractors start with the gross wall area, add the gable triangles, take off the openings and then adjust for how much of the house is included.

• Stories set the wall height. Taller walls also cost more to reach.
• Openings come off as a share of the wall until someone counts them at the house. Measured Bid starts at 10% for siding and 15% for paint.
• Partial jobs use a share of the wall. Half the house is about half the wall area, though the windows may not split evenly.
• Removal of the old siding is priced on the same net wall area as the new siding.
• Trim, corners and flashing are often priced as a percentage of the new-siding line.
• Waste comes from the product maker or the supplier. It should be counted once.

Story count has a big effect on wall area. Here is Measured Bid's one-story sample house, with a 184 ft wall perimeter, measured at each height:

Each added story adds about 1,500 sq ft of wall on that footprint. Check the story count before you trust any price range.

Worked example: a two-story, 1,800 sq ft house

Assumptions for the example house:

• 1,800 sq ft of living space on two equal floors, so 900 sq ft per floor.
• A rectangular footprint, 36 ft by 25 ft.
• 9 ft walls on each story.
• A gable roof at 6/12 pitch, with the ridge running the long way. The 25 ft walls are the gable ends.
• An 18 inch roof overhang on every side.
• Windows and doors take 10% of the wall.

Siding: net wall area and squares

The gable height comes from the pitch. Half of the 25 ft width is 12.5 ft, and a 6/12 roof rises 6 inches per foot, so the peak sits 6.25 ft above the wall.

Roof: sloped area and squares

What the example shows

• The roof is about 12 squares. Using the 1,800 sq ft of living space would have put it at 18 squares, almost 50% too high.
• On this house the walls need more material than the roof: about 21 squares of siding against 12 squares of roofing.
• Turn the ridge the other way and the gables sit on the 36 ft walls. The gable triangles grow from 156 to 324 sq ft. That adds about 1.5 squares of siding to the same house.

A contractor turns these quantities into a price with their own rates. GVX Remodeling publishes its 2026 Vancouver-area ranges in its siding replacement cost guide and its roof replacement cost guide for Vancouver, WA.

What drives the cost of a siding or roof replacement?

Quantities set the base. The choices below move the price from there. The installed prices in this table are the ones GVX Remodeling publishes in its 2026 cost guides.

Roofers often quote per square. To compare, multiply a per-square-foot figure by 100.

Material

GVX's siding guide says the gap between vinyl and fiber cement can double or triple the total for the same house. Its roof guide calls material the single biggest factor in the cost of a roof replacement. For the two engineered products, GVX's LP SmartSide vs James Hardie comparison covers how each one holds up in Vancouver's rain.

Tear-off and layers

Removing the old siding or shingles is its own line. GVX lists $1,000 to $3,000 for a standard tear-off in both its siding and roofing guides. Roof tear-off is priced per layer, so a roof with two layers pays for removal twice. Clark County generally allows no more than two layers of roofing on a home. A house that already has two needs a full tear-off.

Steep pitch

Steep roofs take longer and need more safety equipment. GVX's roof guide says a roof at 8/12 or steeper can add 15 to 25 percent to labor compared with a 4/12 roof. A careful estimate applies that adjustment only to the steep planes.

Stories and access

Multi-story homes need scaffolding and more labor time. Estimates often show this as a multiplier on the siding or roofing line for 2 and 3 story houses.

Trim, openings and flashing

Trim around windows, doors and corners takes more labor per foot than open wall. GVX's siding guide says replacing trim, soffit and fascia along with the siding adds 15 to 30 percent. A house with many windows has less wall to cover. It also has more trim and flashing to install.

How accurate is an address-based price range?

It depends on the house. Aerial data is quick and consistent. It still has blind spots:

• Trees. Roof under heavy trees or deep shade can drop out of the data. Missing roof makes the numbers come in short.
• Old imagery. An addition, a new garage or a porch built after the photo was taken won't be in it.
• Partial roofs. The model sometimes leaves a section out. Measured Bid flags houses with less than 90% of the roof mapped.
• Walls the outline can't explain. Stone or brick sections, walkout basements, porches, bump-outs and detached garages.

Measured Bid has published one accuracy test so far. On 9 invoiced gutter jobs, the quoted gutter footage had a median absolute error of 14.2% and a mean absolute error of 16.2%. Those jobs were also used to tune the engine, so new houses may miss by more. The test covers gutter footage only. No accuracy figure has been published yet for roof area or wall area. Measured Bid lists each job and the method in its published accuracy test.

That uncertainty is why a homeowner sees a range. In Measured Bid, every estimate gets a confidence level. By default the range is plus or minus 10% at high confidence, 15% at medium and 25% at low, and each contractor can change those.

What does an in-home inspection find that an online estimate can't?

An aerial image shows the top of the roof. It can't show what is under the shingles or behind the siding. On a Pacific Northwest house, rain works its way behind old siding and into roof decking, and neither shows up from above.

Behind the siding

• Rot and water damage in the sheathing or framing. It has to be repaired before new siding goes on, and nobody can price it until the wall is opened.
• Older T1-11 and hardboard. When the bottom edges sit close to soil or stay wet, these panels can swell and soften. The damage can run into the sheathing behind them.
• Cedar that has gone too long between coats of stain or paint. GVX's siding guide notes it is prone to splitting and cupping without regular maintenance.
• Flashing and housewrap around windows and doors that is missing or has failed.

On the roof and in the attic

• Moss. It holds moisture against the shingles and can lift their edges. The inspection checks whether it has already done damage.
• Decking. Soft or rotted roof sheathing shows up when someone walks the roof, or after tear-off. GVX's roof guide suggests budgeting a 10 percent contingency for repairs found under the old roof.
• Layers. How many roofs are already on the house.
• Ventilation. Attic intake and exhaust vents, which an aerial image can't judge.
• Flashing at chimneys, skylights and where the roof meets a wall.
• Low-slope sections, such as a porch roof, that need a membrane instead of shingles.

Not sure the roof needs replacing yet? GVX's list of signs you need a new roof in Vancouver, WA covers what you can check from the ground.

Do you need a permit for a roof or siding replacement in Vancouver, WA?

In Clark County, yes. Clark County's residential permits page says re-roofing permits are required for all buildings in Clark County. It also says a permit is required to replace any siding on a structure. Replacing roof sheathing may need a separate permit. Generally, no more than two layers of roofing can be applied to a home.

If your house is inside Vancouver city limits, the City of Vancouver runs its own Permit Center. Its residential building permits page does not list a separate rule for re-roofing or re-siding, so ask the Permit Center directly. The city offers a free 30-minute virtual appointment with permit staff.

GVX Remodeling says it handles the permit on projects that need one. Whoever you hire, ask who pulls the permit and make sure it is on the estimate.

How should you use an online price range?

Use it to set a budget and to check the contractor's quantities.

Before the in-home visit:

• Write down the squares or wall area from the tool, and the imagery year.
• Note anything the aerial can't see, like an addition, a porch roof, stone walls or trees over the roof.
• Find out how many roof layers are on the house, if you can.

At the visit, ask:

• What measured quantity is this estimate based on, and how does it compare with the aerial number?
• Is waste included in the rate or listed separately?
• How are repairs found after tear-off priced and approved?
• Is the permit included?

If the contractor's quantity is far from the aerial number, ask why. There is often a good reason, like a section hidden under trees or a porch roof the aerial missed.

Frequently asked questions

Sources

• Clark County Community Development, Residential permits (roofing, siding and windows)
• Clark County, Roofing, Siding and Windows permit form (PDF)
• City of Vancouver, Residential Building Permits and Permit Center virtual appointments