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Roofing Low-Slope Template

Flat Roof TPO Replacement Proposal Template

Standard scope for residential flat roofs, commercial low-slope buildings, and modern architectural additions using single-ply TPO membrane.

Est. Ticket Size
$9,000 – $32,000
Typical Duration
2–4 Days
Trade Category
Roofing
Governing Standard
2024 IBC Chapter 15 / IRC R905.13

Complete Scope of Work

Copy or customize these verbatim specifications into your contractor proposal.

1

1. Tear-Off & Core Sampling

Removal of failing built-up or modified bitumen roof.

  • Perform core cut test to determine insulation thickness and substrate condition.
  • Tear off existing gravel, tar, or modified bitumen layers down to structural deck.
  • Inspect metal or wood deck for moisture, rust, or deterioration.
2

2. Polyisocyanurate Insulation & Taper System

Thermal insulation and positive drainage cricket slope.

  • Fasten 2-inch closed-cell polyisocyanurate (polyiso) insulation boards with heavy-duty plates and screws.
  • Install tapered insulation crickets between scuppers to eliminate ponding water.
  • Install 1/2-inch high-density cover board for puncture and hail protection.
3

3. TPO Membrane & Robotic Heat-Welded Seams

Single-ply membrane installation.

  • Install 60-mil white reflective TPO membrane (mechanically fastened or fully adhered).
  • Hot-air weld all lap seams using robotic welder (minimum 1.5-inch continuous weld width).
  • Test all seams with cotter pin probe tool to verify 100% monolithic seal.
4

4. Edge Metal, Scuppers & Penetrations

Perimeter termination and drainage components.

  • Install TPO-clad parapet wall drip edge and termination bar with polyurethane sealant.
  • Fabricate and heat-weld prefabricated TPO pipe boots, corner wraps, and scupper boxes.
  • 20-Year manufacturer material warranty and 5-year contractor workmanship warranty.

Standard Line-Item Material Allowances

Clear material specifications that protect against ambiguous scope arguments.

Component / AssemblyStandard SpecificationUnit / Allowance
60-Mil White TPO MembraneEnergy Star rated heat-reflective single-plyPer Square
Polyiso Insulation (R-12+)2-Inch 20 PSI rigid polyisocyanurate boardsPer Board
High-Density Cover Board1/2-Inch primed gypsum or polyiso cover boardPer Board
TPO-Clad Drip Edge Metal24-Gauge Galvalume with factory-laminated TPOLinear Feet
Prefabricated TPO Pipe BootsInjection molded heat-weldable bootsPer Unit

Scope-Gap Protections: 3 Clauses to Include

These contractual gotchas account for 85% of change-order arguments on flat roof tpo replacement proposal templates.

Ponding Water on Inadequately Pitched Decks

The Risk: Water ponding longer than 48 hours voids many single-ply manufacturer warranties.

Protective Clause: Specifies tapered polyiso crickets to direct water toward scuppers or internal drains.

Degraded Metal Decking Under Old Roofs

The Risk: Corroded corrugated steel decking cannot hold insulation fasteners.

Protective Clause: States scope includes inspection; rusted deck panels requiring replacement will be billed at $X per square foot.

Parapet Wall Moisture Infiltration

The Risk: Water entering porous masonry coping stones above the roof line creates leaks blamed on the new roof.

Protective Clause: Clearly marks termination height and specifies metal coping cap upgrades as an optional addendum.

Governing Building Codes & Standards

2024 IBC Chapter 15 / IRC R905.13UL Class A Fire RatingASTM D6878 TPO Standard

Frequently Asked Questions

Why is 60-mil TPO recommended over 45-mil for low-slope roofs?▾

60-mil TPO provides a 33% thicker weathering layer, superior puncture resistance against foot traffic and tree debris, and qualifies for extended 20-year manufacturer warranties.

Does a white TPO roof lower cooling energy costs?▾

Yes. Highly reflective white TPO has a Solar Reflectance Index (SRI) over 100, reflecting up to 80% of the sun's rays and significantly reducing attic and cooling loads.

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