What actually drives the price of a roof
Any website that gives you a price before somebody has measured your roof is running a lead magnet, not a quote. What can be published honestly is the list of things that move the number, and how to read two bids that look wildly apart.
- Sheet
- A04
- Subject
- Price drivers and bid comparison
- For
- A homeowner holding two bids
- Trade
- Roof replacement
The nine drivers
| Driver | Why it moves the number |
|---|---|
| 01 Squares | The measured roof area in hundreds of square feet. This is the base of everything and it is the one number every bidder will give you. |
| 02 Pitch | A roof steep enough that a crew cannot stand on it comfortably takes staging, more time and more caution. Past a certain steepness the labour cost stops being linear. |
| 03 Complexity | Linear feet of valley, hip, ridge, sidewall and headwall. Cut up roofs eat material in waste and eat labour in detail work. This is the driver most homeowners have never heard of and it is often the largest single difference between two houses. |
| 04 Layers | Tear off of two layers is close to double the strip labour and close to double the disposal weight of one. |
| 05 Decking | Nobody knows the condition until the shingle is off. This should appear in a bid as a stated unit price per sheet or per board, not as a blank. |
| 06 Penetrations | Boots, flues, chimneys, skylights, satellite mounts, solar mounts. Each one is a hole in the roof that has to be made watertight by hand. |
| 07 Access and staging | Where the dumpster goes, whether the drive will take it, walkout elevations, tight side yards, and whether the crew is carrying material up or craning it onto the roof. |
| 08 Ventilation work | Cutting a ridge for a ridge vent, adding box vents, opening blocked soffit intake. Real work with a real cost and a real return. |
| 09 Gutters | Often bundled and often not. Gutter is a separate material and a separate day, and it should be a separate line on the paper. |
Reading two bids that are far apart
A homeowner with two roofing bids that differ substantially usually assumes one company is greedy and the other is a bargain. Occasionally that is true. Far more often the two bids are describing two different pieces of work, and the difference is legible on the paper if you know the six places to look.
- Squares, and whether they were measuredIf the two square counts differ by more than a rounding, one of them did not measure. Ask how the number was arrived at.
- Tear off or layoverA layover bid will always be cheaper and it should be, because it is a different and worse job. Make sure you are comparing two tear offs.
- DeckingOne bid carries a unit price for replacement decking and a note that it is charged only if used. The other says nothing, which means the conversation happens on the day when you have no leverage.
- Ice and water barrierWhere is it going, and how far up from the eave. In the valleys as well, or only at the eaves. This is a real material cost and a real difference in the roof.
- FlashingNew step flashing, or reuse of what is there. Reuse is cheaper and it is the single most common hidden compromise in this market.
- VentilationIf one bid includes cutting in a ridge vent and the other does not, they are not the same roof when they are finished.
The cheapest useful question
Ask each bidder: what nailing pattern do you use, and how many nails per shingle. It takes ten seconds, the answer is verifiable against the manufacturer's own instructions, and the way somebody answers it tells you whether you are talking to a roofer or to a salesman.
Two things that should worry you about a number
A price produced in your driveway, from a tablet, within twenty minutes of a knock at the door, after a storm, is a price produced without anybody knowing how many layers are on your roof or what condition the deck is in. It is not a quote, it is an opening position, and the real number arrives later when the roof is already open.
A price that is only good until the end of the visit is a pressure technique and nothing else. Roofing material and roofing labour do not become cheaper because you signed on a Tuesday evening. Any honest bid is still honest on Friday.
Neither of those means the company is a fraud. It means the pricing is designed around closing rather than around the roof. A written scope, measured, with the decking unit price on it and no expiry attached, is the thing you are actually shopping for, and it costs a contractor nothing to give you except the ability to pressure you.