How to Bid a TPO Roof in Kansas City: A GC's Complete Guide

Bidding a TPO commercial roofing project in the Kansas City metro requires more than just square footage and a unit price. General contractors who have worked with us know that a well-scoped TPO bid prevents change orders, schedule delays, and warranty disputes down the road. This guide walks through every step.

What Is TPO and Why Is It the Most Specified Commercial Membrane?

Thermoplastic Polyolefin (TPO) is a single-ply roofing membrane that has become the dominant choice for commercial flat and low-slope roofs over the past two decades. It offers excellent UV resistance, heat-weld seams that are stronger than the membrane itself, and competitive pricing compared to PVC. In Kansas City's climate — with freeze-thaw cycles, summer heat, and hail — TPO's flexibility and impact resistance make it a strong default specification.

Johns Manville's TPO systems, which Pro Roofing KC installs as a Preferred Partner, are available in 45, 60, and 80-mil thicknesses and carry NDL warranties up to 30 years when installed by a certified contractor.

Step 1: Review the Plans and Specifications

Before submitting a number, confirm the following from the project drawings and spec book:

• Membrane thickness: 45-mil, 60-mil, or 80-mil. Most commercial specs call for 60-mil minimum.
• Attachment method: Mechanically attached, fully adhered, or ballasted. Fully adhered costs more in labor but is required for high-wind zones and most warranty tiers.
• Insulation type and R-value: Polyiso is standard. Confirm whether tapered insulation is required for drainage.
• Warranty tier required: 10, 15, 20, or 30-year NDL. Each tier has different material and installation requirements.
• Deck type: Steel, concrete, or wood. Affects fastener type and pull-out values.
• Penetrations and details: HVAC curbs, drains, skylights, and parapet walls all add labor. Count them on the plans.

Step 2: Scope the Takeoff Accurately

A TPO takeoff includes: field membrane square footage, linear feet of seams, perimeter edge metal (coping, drip edge, gravel stop), flashing at all penetrations and walls, insulation layers, cover board if specified, and fastener count for mechanically attached systems. Missing any of these is where bids go wrong.

Pro Roofing KC uses STACK takeoff software for all commercial bids, which allows us to share a digital takeoff with the GC for verification before submitting a number.

Step 3: Understand the Warranty Requirements

If the spec requires a manufacturer's warranty (and most commercial projects do), the roofing sub must be a certified installer for that manufacturer. Pro Roofing KC is a Johns Manville Preferred Partner and GAF Master Elite® Contractor, which means we can issue NDL warranties up to 30 years on qualifying systems. Ask your sub to confirm their certification level before bid day.

Step 4: What to Include in the Bid Package

A complete TPO bid from a qualified sub should include: base bid with alternates, material cut sheets and data sheets, installer certification documentation, insurance certificate (GL, Workers Comp, Umbrella), EMR letter, and a preliminary submittal schedule. If the project requires prevailing wage, confirm the sub's certified payroll process.

Step 5: Award and Submittal Timeline

Once awarded, expect the following submittal timeline from Pro Roofing KC: product data and shop drawings within 5 business days of award, warranty application submitted to manufacturer within 10 days of award, and pre-installation meeting scheduled before mobilization. We provide a full submittal log to your project manager so nothing falls through the cracks.

Ready to Bid?

Pro Roofing KC serves the Kansas City metro and 16 states. Send us your plans at [email protected] or call 816-429-ROOF. We respond to all bid invites within 24 hours.