Roof Replacement Cost for a 4,000 Sq Ft House in Ontario, CA

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Roofers price the roof, not the house. A one story 4,000 sq ft home can have about twice the roof of a two story one, per This Old House.
Inland California shingle roofs run about $6 to $9 per square foot and tile about $12 to $21, per RoofingCalc (March 2025).
Pitch adds area. A 4 in 12 roof has a pitch factor of 1.054, per Vertigraph.
Eaves and the garage add roof that is not in your living space. Waste adds about 10 to 15 percent to the material order, per Vertigraph.
The national average of about $14,498 is built mostly on asphalt roofs, per This Old House. It says little about a tile roof in Ontario.
Many Ontario tile roofs only need new underlayment, which can skip the cost of new tile.

Why the Price Range Is So Wide

We see a lot of homeowners in Ontario Ranch, Eastvale and Rancho Cucamonga who looked up a roof price for their house size and got a number that made no sense. One site said $14,000. A roofer said $45,000. Both can be right.

The biggest mistake is pricing your living space. Your 4,000 square feet is floor area. A roofer measures the roof surface. Those are two different numbers, and on a big house the gap can be thousands of square feet.

This Old House shows how big the gap gets. Using a 6 in 12 pitch and one foot eaves, it models a one story 4,000 sq ft home at about 4,849 square feet of roof and a two story one at about 2,473 (This Old House). Its average cost for the one story is $28,158. For the two story it is $14,360. Same living space. About double the price.

The second mistake is pricing the wrong material. That same page gives a headline average of about $14,498 for a 4,000 sq ft home, but 75 percent of the homes behind it are asphalt (This Old House). Most tract homes from the 1980s to the 2000s around Ontario wear concrete tile. A national shingle average does not fit them.

Roofer measuring a shingle roof slope with a tape — A roofer measures the slope of a roof. Pitch is one reason roof size is bigger than the house footprint.

How to Turn House Square Feet Into Roof Squares

Roofers count in squares. One square is 100 square feet of roof surface (Vertigraph). A roofer gets from your house size to squares in steps.

Step 1. Find the footprint. Divide your living space by the number of stories. A one story 4,000 sq ft house covers about 4,000 square feet of ground. A two story one covers about 2,000.

Step 2. Add the eaves. The roof hangs past the walls on every side. In our worked example we use 18 inch eaves. On a 50 by 80 foot one story house, that turns 4,000 square feet into about 4,400.

Step 3. Add the garage and patio covers. An attached garage is roofed but is not part of your living space. A 20 by 20 two car garage adds about 530 square feet of roof once you count eaves and pitch, in our worked example.

Step 4. Multiply by the pitch factor. A sloped roof has more surface than the flat area under it. The factor for a 4 in 12 pitch is 1.054 and for a 6 in 12 pitch is 1.118 (Vertigraph). The formula behind it is the square root of the rise over run squared, plus one (Omni Calculator).

Step 5. Know what waste does. Shingles get cut at every hip, valley and edge. Vertigraph puts waste at about 10 percent on a simple gable and 12 to 15 percent on a hip roof (Vertigraph). Waste raises the material order, not the size of your roof. Ask each roofer whether their price per square is on the measured roof or on the order with waste. Then compare quotes on the same basis.

The table below runs those steps for a one story and a two story 4,000 sq ft house with a 4 in 12 hip roof. It is a worked example, not a measurement of your home.

Worked example. 4,000 sq ft of living space, 4 in 12 hip roof, 18 inch eaves, garage not included. Pitch factor and waste ranges from Vertigraph.
Step	One Story	Two Story
Footprint	4,000 sq ft (50 x 80)	2,000 sq ft (40 x 50)
With 18 inch eaves	About 4,400 sq ft	About 2,280 sq ft
Times 1.054 pitch factor	About 4,640 sq ft	About 2,400 sq ft
Roof squares	About 46	About 24
Material order with 12 to 15% hip waste	About 52 to 53 squares	About 27 to 28 squares

What It Costs in Shingle and Tile

For prices, we use the California ranges from RoofingCalc, dated March 30, 2025. It puts architectural shingle at about $6 to $9 per square foot installed in inland areas like the Inland Empire, and tile at about $12 to $21 (RoofingCalc). On our worked example homes, those ranges work out as follows.

One story, about 4,640 square feet of roof. Shingle runs about $27,800 to $41,800. New tile runs about $55,700 to $97,400.

Two story, about 2,400 square feet of roof. Shingle runs about $14,400 to $21,600. New tile runs about $28,800 to $50,400.

Add the garage from Step 3 and the numbers climb. At about 530 square feet, a two car garage adds about $3,200 to $4,800 in shingle or $6,400 to $11,100 in tile, using the same per square foot ranges.

Compare that to the national numbers. This Old House lists a 4,000 sq ft clay tile roof at about $36,724 as a national figure (This Old House). That is close to our two story tile range. It is far below what a one story tile roof here can cost.

Tile does not always mean new tile. Many tile roofs in Ontario still have sound tile with worn out paper under it. A re-lay lifts the tile, puts down new underlayment and sets the same tile back. That can cost far less than new tile. Our tile roofing page explains how a re-lay works, and our post on the most expensive part of replacing a roof breaks down where tile money goes.

New Roof Cost on a 4,000 Sq Ft House

Two story, shingle$14,400 to $21,600
Two story, new tile$28,800 to $50,400
One story, shingle$27,800 to $41,800
One story, new tile$55,700 to $97,400

Worked example from RoofingCalc's California ranges (March 2025), shingle $6 to $9 and tile $12 to $21 per sq ft, on about 4,640 sq ft of roof (one story) and 2,400 sq ft (two story). Garage not included.

Two neighboring homes, one with a clay tile roof and one with an asphalt shingle roof — A tile roof and a shingle roof side by side. On the same size house, tile usually costs about twice as much.

Other Costs on a Big Roof

Tear off and disposal. RoofingCalc lists disposal at about $0.40 to $0.90 per square foot in California (RoofingCalc). On our one story example, that is about $1,860 to $4,180. On the two story, about $960 to $2,160. Ask if it is already in the price.

Extra layers. Each layer beyond two adds about $1 to $2 per square foot, per the same guide (RoofingCalc). Older shingle ranches sometimes hide a second layer.

Rotten wood. Spot deck repairs run about $2 to $4 per square foot in California (RoofingCalc). Nobody knows how much is bad until the old roof is off. A good quote says how wood will be priced.

Permit. RoofingCalc puts California roofing permits at about $200 to $800, or $300 to $1,000 in seismic or fire zones (RoofingCalc). Your roofer should pull it.

Height. A two story roof has less area but is harder to work on. Staging, safety lines and carrying tile up two floors cost labor. That is why the two story price is not exactly half the one story price in real quotes.

How to Check a Quote on a 4,000 Sq Ft House

Get at least three written quotes. Then check one number first. How many squares did each roofer measure? If one says 46 and another says 30 on the same house, someone measured wrong or left out the garage.

Next, check what is under the price. New tile or re-laid tile. Tear off down to the deck or not. Underlayment type. How wood repair is priced. Who pulls the permit.

Our $30,000 roof guide shows how to line up quotes item by item and covers California's down payment limit. If you are not sure whether you need a full new roof, a roof inspection with photos answers that before you spend this kind of money.

All prices are as of October 2026 and come from the cited guides. Your roof will price on its own size, pitch, material and condition.

If your home is in Ontario or the west Inland Empire, call Ontario Roofing at (909) 404-9464 for a free written estimate that lists the squares we measured.

People Also Wonder

How many squares is a roof on a 4,000 square foot house?

It depends on stories and pitch. In our worked example with a 4 in 12 roof and 18 inch eaves, a one story 4,000 sq ft house has about 46 squares and a two story one about 24, before the garage. One square is 100 square feet, per Vertigraph.

How much is a tile roof on a 4,000 sq ft house?

Using California tile prices of about $12 to $21 per square foot from RoofingCalc, a two story home with about 2,400 square feet of roof runs about $28,800 to $50,400. A one story home with about 4,640 square feet of roof runs about $55,700 to $97,400. A re-lay with new underlayment usually costs less.

Is a new roof cheaper on a two story house?

Usually yes, because a two story house has about half the footprint. This Old House puts the average at $14,360 for a two story 4,000 sq ft home and $28,158 for a one story one.

Does the garage count in roof square footage?

Yes. The garage is roofed even though it is not living space. A 20 by 20 two car garage adds about 530 square feet of roof in our worked example.

Why do roofing quotes for the same house differ so much?

Most often the roofers measured different square counts or priced different work, like new tile versus re-laid tile. Ask each one how many squares they measured and what is included.

What is the waste factor on a roof?

It is extra material for cuts. Vertigraph puts it at about 10 percent for a simple gable roof and 12 to 15 percent for a hip roof.

Further Proof

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