Running a call for tenders for a commercial roof

One text for everyone: the specifications

The written specifications are the central document in managing roofing work. The price, the contract and the settling of a disagreement depend on them. An engineer, an architect or a roofing consultant can write them. For a small project, a manager can build them from a detailed inspection report.

For quotes to be comparable, the specifications should contain:

• a roof plan, with the area and the sections to redo,
• what happens to the old covering, fully torn off or covered over,
• the new assembly described layer by layer, thicknesses included,
• what is done with drains, parapets, flashings and equipment curbs,
• the colour or reflectance of the covering, according to what the City requires,
• the building's conditions: permitted hours, access, sensitive units,
• the warranties required and the maximum length of the job.

The reflectance line in Laval

Section 380 of the Code de l'urbanisme (Laval's urban planning code) covers main and accessory buildings with a flat roof. It requires a green roof, a white or whitened material (paint, reflective coating, white ballast), or a material with a solar reflectance index of at least 78. The Code does not say what applies to an existing roof redone identically.

The City publishes no process page specific to the roof of a commercial building, and its no-permit rule for the same material is written for a residence. Put your questions to the City's Service de l'urbanisme (urban planning department) before sending out the specifications.

The price of what no one can see

Deck and insulation stay hidden until tear-off. Require from each bidder a unit price for work that cannot be measured in advance, such as replacing a given area of deck or wet insulation. You then compare the base price and the price of bad surprises.

The group roof visit

An aerial photo is not enough to price a roof. Invite the bidders to a visit, ideally as a single group. Each one then sees the same thing: access, height, room for the crane, condition of the upturns. The bidders go up, and you collect their questions below.

Record the questions asked. Answer in writing, to everyone, in the same mailing. An answer that changes the specifications is issued as a written addendum.

Six points to announce besides price

Write in the call for tenders what you will look at.

1. Licence. In Quebec, a construction contractor must hold a licence from the Régie du bâtiment du Québec (RBQ, Quebec's building authority). The RBQ's public register lets you check it.
2. Liability insurance. Proof of a policy in force.
3. Similar jobs. Same size, same system, occupied building.
4. References. Reachable managers, for roofs delivered a few years ago.
5. Staff. The designated foreman, their presence on site, the planned subcontractors.
6. Warranties. Manufacturer on one side, workmanship on the other, each with its conditions.

Reading the responses

A table is enough: contractors in columns, the lines of the specifications in rows.

• Exclusions first. The list of what is missing often tells you more than the rest.
• The system next. Make sure each bidder priced the one in the specifications, not an equivalent of their own.
• A price well below the others deserves a question. An item may have been left out.

Frequently asked questions