TPO calculator

1

Roof size

Area of the roof section being replaced.

Length (ft)

Width (ft)

2

Existing roof

What comes off: one layer of smooth or coated roofing (mod-bit, smooth built-up, TPO, PVC or EPDM) and the insulation under it.

There may be more than one roof layer The roof has gravel or loose rock on it

3

New roof

Budget basis: 60-mil white TPO over R-25 insulation, with a 20-year manufacturer No Dollar Limit warranty allowance. Eligibility and final specifications require confirmation.

Attachment

Mechanically attachedFastened in the seams. Most common on steel deck. Fully adheredBonded to the insulation. Quieter in wind.

Insulation

This budget model assumes R-25 polyiso in two staggered layers, fastened to the deck. Required insulation, attachment and code compliance must be confirmed for the actual project.

Vapor barrier on the deck

NoneInsulation directly on the deck 6-mil polyPolyethylene, laps taped Self-adheredBonded vapor barrier for humid interiors

4

Roof edges

Linear feet around the roof section, by how it ends.

Edge metal (LF)Gravel stop or drip edge

Walls and parapets (LF)Flashed up a wall or curb

Gutter edges (LF)Edge drains to a gutter

5

On the roof

Count each item that has to be flashed into the new roof.

HVAC unitsCurbed rooftop units

Small curbsFans, hatches, skylights

Pipes and vents

Roof drains

6

Building height

Sets how material and debris move on and off the roof.

1 story 2 stories 3 stories 4+ stories