Bids on roofing can be written up in many different ways, but when comparing, we must normalize the bids so that we can see if there are any price differences for actual differences in scope and quality versus unbudgeted differences in how the information was presented. In other words, price differences must reflect differences in scope and quality and not just the contractor’s lack of completing the quote in adequate detail.
Reading estimates for scope, not just for price
Require all bidders to list out tear-off, decking repair, underlayment, flashing, ventilation and disposal in separate line items. Make sure that “re-use existing step flashing” is reflected in the tear-off line and not as a reduction to the ‘decking’ line. This allows for apples to apples comparison of bids that may otherwise appear to be vastly different due to scope not being fully articulated.
Decking is one of the biggest components of a roof and a major cost factor. It’s not uncommon for contractors to have an allowance for a fixed number of decking sheets in their tender. It could be priced out on a unit rate basis after they have completed the tear-off. Others may not even quote for it. It looks cheaper at first but ends up being the most expensive option in the long run.
Allowances and contingencies to isolate
- Sheathing replacement, priced per sheet or per square foot
- Chimney and skylight flashing, replaced versus reflashed
- Ventilation modifications required to meet code or manufacturer specification
- Permit fees and inspection scheduling responsibility
- Disposal, including whether dumpster placement and driveway protection are included
Separating workmanship warranties from material warranties
Workmanship warranties on the other hand are typically offered by the installer. While material warranties cover defects in the materials used in a roof, workmanship warranties cover failures that can occur as a result of the installation. That means a shingle with a thirty year warranty that has been installed with the wrong nailing pattern will fail long before the thirty years are up, and the manufacturer’s warranty will not cover the claim.
Check how long the workmanship warranty is good for, whether or not it will transfer to new owners of a home, whether both labor and materials are covered during any repairs, and what will void the workmanship warranty. Many roofing companies offer 2 year workmanship warranties, but a 10 year or more warranty indicates a very financially stable company that is planning on being around for a long time.
Manufacturer certification as a proxy
To promote quality installation, manufacturers have developed Certified Installer programs. To become certified, installers must complete manufacturer-approved training sessions and provide documentation of past work that can be reviewed for past claim activity. It is worth shortlisting a certified Woodbridge Township roofing company, because work completed by a certified installer can often be covered under an extended system warranty that lasts longer than the typical workmanship warranty.
Comparing material specifications line by line
When comparing bids for architectural shingles, compare the exact manufacturer, product line, and color of shingle as well as the detailed specification for underlayment, ice and water shield coverage, drip edge, and fasteners. Synthetic underlayment installed on the full deck of shingles is far from the same as installing felt underlayment at the eaves only.
Flashing, Be sure to note the gauge of the flashing metal (i.e., thickness) and whether it has been painted. Flashed with painted aluminum, galvanized steel or even copper, the roof would likely last as long as the corresponding material. A bid which does not specify the type of flashing to be used may end up utilizing the least expensive of the above mentioned materials.
Building a scored comparison
Turning to evaluating bids, these should be scored against a set of criteria and the scores added up to arrive at an ‘aggregate review score’. A sample criteria score sheet is provided below. Importantly, who you compare is very important, i.e. A shortlist of established local companies with lots of verifiable recent history will likely score very differently than a long list of ‘triggered’ lowest bidders.
| Criterion | Strong signal | Warning sign |
| Estimate detail | Itemized scope with unit rates for discovered work | Single lump sum, verbal allowances |
| Workmanship warranty | Ten years or more, transferable, labor included | Under two years, or undefined in writing |
| Material spec | Product line and accessory components named | Generic category descriptions only |
| Insurance | Current general liability and workers’ compensation certificates | Certificates promised but not produced |
| Crew arrangement | Named site supervisor, employed or long-term subcontracted crew | Crew assigned after contract signing |
Testing communication before you commit
Finally, remember that the process of soliciting bids is a strong indicator of how a particular contractor will behave when you hire them to do your roof. Track the length of time it takes for potential contractors to get back to you with a revised estimate. Find out if they will answer your questions directly. See if they actually put a ladder up against your house instead of just using a satellite image of your roof to measure it.
Questions that reveal process
- Who is on site daily, and how are change orders documented and approved?
- What is the notification process if weather stops work mid tear-off?
- How is the final inspection conducted, and what does the punch list look like?
Verifying reputation with evidence
Aggregate review scores (even Average Rating Truescore (ART) or Average Rating (AR)) are weak indicators of quality. Much stronger indicators include, a) confirmation through state licensing board(s) of the contractors’ current (as opposed to past) license(s); b) a clean record with the local building department; c) reference checks with at least 3-5 year old installations where inevitable problems with the roof have had a chance to reveal themselves.
When asking references for past customers, it is better to ask how the roofer handled problems that came up after the install, rather than how they felt about the roofer after the job was done. Every roof develops a problem, and how a roofer responds to that problem is the most important factor.
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