Check Each Roof Bid Against the County Assessor's Record Before You Compare

Every roof bid starts with a number for the size of the roof, and that number drives the material count, the labor, and the price per square. Most homeowners compare the totals and never ask where the size came from. Before you line up two or three bids, pull the parcel record for your address from the county assessor and read it next to what each roofer wrote down. The record will not measure your roof. It can still show you when one bid is working from a different house than the one you own.

What the assessor record holds

St. Louis County and the City of St. Louis each keep property records through their own assessor offices, and the layout of the online record differs between them. For a single-family house you can usually find the parcel number, the year the house was built, the living area in square feet, the number of stories, and the lot size. Some records list a finished basement area, a garage size, or a count of bathrooms. The record exists for taxation, so the figures are the assessor's estimates and may be years old if no one has looked at the house since a remodel.

What the record does not give you is roof area. The living area is the heated space measured on the floors. A steep roof, a dormer, a front porch, and a garage roof all sit on top of or beside that space, so a roof can cover more or less ground than the living area suggests. A roof bid that comes in well away from the living-area math is not automatically wrong, but it is a number that needs an explanation. A rough check is to take the living area for the main floor, add the overhang at each eave, and compare that with the square count on the bid. If the bid is far above that figure, the extra surface should be visible somewhere in the drawing or the description.

Read the bids against the record

Gather each roofer's written bid and find the line where the roof area or the square count appears. Most bids state it in squares, where one square is 100 square feet of roof surface. Write the figure beside the parcel's living area and the number of stories. Then ask each roofer one plain question: what did you measure, and what did you use as the starting point?

Good answers name the source. A roofer who walked the roof and sketched each plane will describe the sketch. A roofer who used aerial imagery will say so and should name the date of the image. A roofer who quoted from a drive-by or from the homeowner's description will say that too. The answer tells you how much weight to put on the number. A bid built on a sketch you can see is easier to check than one built on a guess, and a bid that cannot name its source is telling you something about the rest of the paperwork.

Watch for a pattern rather than a single gap. If one bid comes in near the living area plus a normal overhang, and another comes in well above it, ask the second roofer what the extra surface is. Sometimes it is a real feature: a second dormer, a front porch with its own roof, or an attached garage. Sometimes it is a rounding habit. Either way, you can now point to a specific area and ask whether it is in the scope.

Where the assessor number and the roof disagree

Three things commonly explain the difference, and each one is worth raising with the roofer before the bid is final. The first is an addition. If a room was added after the record was last updated, the living area in the record will be too small and the roof will be too big. Ask whether the roofer saw the addition from the ground and whether it has its own roof lines that need to be counted separately.

The second is the garage and any detached structure. The assessor often lists the garage as a separate area, and a detached garage on the same lot has its own roof. Many bids quote the house and the garage as one number. Ask each roofer to split the two so you can see whether the garage is included, priced apart, or left out. A garage left out of one bid and included in another will make the totals look far apart even when the roofs are the same.

The third is pitch. A low-slope roof and a steep roof over the same footprint have different surface areas. The footprint from the record does not tell you the pitch, so the roofer's pitch note matters. Ask each roofer to state the pitch used for each plane, and ask what they did if the pitch was estimated from the ground rather than measured on the roof.

What to ask each roofer

1. Which source did you use for the roof area, and what date is on it?
2. Does your square count include the house, the garage, and any porch or dormer, and where is each one listed?
3. What pitch did you use for each plane, and how did you confirm it?
4. Did you see any addition or change that the county record might not show?
5. If I hand you the parcel record, will you tell me where your number differs from it, and why?

Write the answers beside the square count on your comparison sheet. A roofer who answers all five in plain terms has given you a number you can check. A roofer who answers the first question by going straight to the price is telling you something too, and it is worth noting in the same column.

Keep the assessor record out of the contract

The parcel record is a tool for your comparison, not a document for the contract. Do not put the assessor's square footage into the scope as if it were the roof area. The contract should carry the square count the roofer measured, the materials named by product, and a line that says what happens if the measured area changes after the permit is pulled. Ask whether the price changes per square and how any change would be written up before the work starts.

If the bids disagree by a wide margin on area, ask the roofers to measure the same way. Give each one the same lot sketch and the same list of structures to include, such as the house, the garage, the porch, and any shed with a roof. This does not fix a bad measurement, but it shows whether the gap is in the measuring or in the pricing. If the areas match and the prices still differ, the comparison has moved to labor and materials, which is a different conversation.

Missouri and permits

Missouri does not license roofers, so the assessor record does not tell you whether a roofer is qualified, and it does not tell you whether a roofer is registered with anyone. Permit requirements come from the municipality or the county where the house sits. Some permit desks may ask for the roof area on the application, so a figure that differs from the record may need to be reconciled before the permit is issued. Ask who files the permit, which figure goes on it, and whether the permit figure will match the contract figure.

If you want to put the question to a roofer directly, the office number for Keys Roofing is (314) 220-2333. Ask for the square count, the source of the number, and the pitch used on each plane, and keep the answers in writing with the rest of your comparison.