Scope the full tile reroof assembly

Look below the roof covering

A useful reroof proposal names each layer and transition that will be evaluated. That includes the deck, underlayment, flashings, valleys, battens or direct-deck attachment, eave treatment, ventilation components, and tile fastening approach. The exact design depends on the existing structure, tile product, slope, exposure, manufacturer instructions, and applicable requirements. Avoid a scope that says only remove and reset tile. That wording leaves the water-management system and concealed repair allowances undefined.

Follow water through the details

Ask how the assembly will handle water at valleys, sidewalls, headwalls, chimneys, skylights, plumbing vents, roof drains, and changes in slope. Tile and flashing should support an uninterrupted drainage path at the surface, while underlayment-level details provide secondary protection. Debris, mortar, fasteners, or poorly placed transitions can obstruct that path. The proposal should describe preparation and tie-ins for each condition present on the building, supported by detail drawings or manufacturer references when useful.

Price concealed conditions honestly

The deck cannot be fully judged until removal exposes it. Require a stated method for documenting unsuitable sheathing or framing, obtaining approval, and pricing additional work before it proceeds. Clarify whether insulation, fascia, gutters, skylights, solar attachments, and interior damage are outside the roofing scope. Define daily dry-in and material staging expectations. At closeout, collect photos of the exposed deck, underlayment, critical flashings, and completed tile—not only finished street views. Those records matter because the most important reroof work soon becomes hidden.

• List every penetration before bidding
• Require written approval for concealed repair changes
• Keep product instructions with closeout records

Check the proposal against the actual roof

Walk the property from the ground with the bidder and label roof planes on a sketch. Match every visible wall, valley, chimney, skylight, pipe group, solar area, and change in height to a scope note. Ask which detail standard or manufacturer instruction will guide unusual conditions. If a section is excluded, show it on the same sketch. This simple review exposes gaps that a material allowance cannot solve. It also gives the completion photos a shared location system and helps owners understand where an alternate or concealed-condition allowance may apply. Confirm how the proposed assembly will terminate at roof areas that are not being replaced. The boundary between new and remaining work deserves its own detail and inspection record.