The common specification
The specification tells every bidder what to price. It can be written by an engineer, an architect or a roofing consultant. On a smaller project, a property manager can put it together from a detailed inspection report.
The price, the contract and the settling of disagreements all follow from it.
A useful specification states:
- the area and sections covered, with a plan
- full tear-off or recover
- the assembly of the new roof, layer by layer, with thicknesses
- how drains, parapets, flashing and equipment curbs are handled
- the borough's requirements, including reflectance where applicable
- the building's constraints, such as working hours, access and sensitive areas
- the warranties required and the maximum length of the job
Unit prices for the unexpected
The condition of the deck and insulation is unknown until the roof is torn off. Ask each bidder for a unit price for work that cannot be measured in advance, for example replacing a given area of deck or wet insulation.
You then compare bidders on the base price and on the price of surprises.
The site visit
No serious bid is prepared from aerial photos. Organize a roof visit for the bidders, preferably all together. Everyone then sees the same conditions, such as access, height, room for a crane and the state of the upstands.
Write down the questions and send the answers in writing to everyone on the same day. If an answer changes the specification, issue a written addendum.
Criteria beyond price
Announce your criteria in the call for tenders.
- Licence. Every contractor must hold a licence from the Régie du bâtiment du Québec. Ask each bidder for their licence number and check it in the RBQ public register.
- Insurance. Proof of current liability insurance, required from each bidder.
- Comparable experience. Projects of the same size, with the same system, on occupied buildings.
- References. Property managers you can call, for work completed a few years ago.
- The crew. The foreman's name, how often the foreman is on site, and the use of subcontractors.
- Warranties. The manufacturer's and the workmanship warranty, with their conditions.
Comparing the bids
Draw up a simple grid, one column per bidder and one row per item in the specification.
- Read the exclusions. What is left out often tells you more than what is included.
- Check that each bidder priced the system requested, not an equivalent of their choosing.
- Ask questions about a price far below the others. The bidder may have missed an item.
Frequently asked questions
How many bids should you get?
Asking for three bids is common practice. Three offers give a good view of the market without making the analysis too heavy.
Can each roofer propose their own system?
Yes, each roofer can propose their own system, but as an alternate, in addition to the price for the specified system. You keep a common basis for comparison while benefiting from each bidder's ideas.
Should you be wary of the lowest bid?
No, not on principle. You need to understand why that bid is lower. If the gap comes from a reduced thickness or an exclusion, the price is no longer comparable.