What flat and low-slope mean on a measurement report
Low-slope generally means a roof plane at or below roughly a 2:12 pitch, close enough to horizontal that the pitch multiplier barely changes the footprint area. Flat roofs sit at the low end of that range, sometimes built with a slight taper for drainage that a report will not capture as a separate pitch.
These roofs are usually membrane systems: TPO, EPDM, modified bitumen, or built-up roofing, sometimes with a ballast or paver layer. The report still expresses area in squares, 100 square feet equals 1 SQ, the same unit used on pitched roofs, so the figures reconcile the same way once they land in the estimate.
Where a low-slope roof differs is in the features it adds that a simple gable or hip roof does not have: parapet walls around the perimeter, roof drains or scuppers instead of gutters, and a higher count of mechanical penetrations because HVAC equipment sits on the roof deck itself.
The measurements a low-slope report captures
- Total roof area (SQ and sq ft)
This is the footprint of the membrane, and it drives the quantity for tear-off, insulation, and new membrane line items.
- Perimeter (linear feet)
Perimeter length sets the quantity for edge metal, gravel stop, or termination bar where the membrane is not bounded by a parapet.
- Parapet wall length and height
Parapets are reported as their own linear-footage figure with an average or banded height, because coping cap and wall flashing material and labor scale with height, not just length.
- Drains and scuppers (count)
Each drain or scupper is a discrete line item for replacement or resealing; the count also flags whether the roof relies on internal drains, which matters if ponding is noted separately in the file.
- Penetrations (count, grouped by size)
Pipe boots, vent stacks, and equipment curbs price per each and often per size class, so the report groups them rather than folding them into the area figure.
Why the pitch multiplier barely moves at low slope
The multiplier is derived the same way on every roof: multiplier = square root of (rise squared plus run squared) divided by run. On a low-slope roof the rise is small relative to a 12 inch run, so the multiplier stays close to 1.00.
The table below applies that formula at 0, 1, and 2 in 12, then shows 4 and 6 in 12 for comparison against steep-slope territory, using a 3,000 sq ft footprint.
| Pitch | Multiplier | Area on a 3,000 sq ft footprint |
|---|---|---|
| 0:12 (flat) | 1.000 | 3,000 sq ft (30.00 SQ) |
| 1:12 | 1.004 | 3,012 sq ft (30.12 SQ) |
| 2:12 | 1.014 | 3,042 sq ft (30.42 SQ) |
| 4:12 (reference, steep-slope) | 1.054 | 3,162 sq ft (31.62 SQ) |
| 6:12 (reference, steep-slope) | 1.118 | 3,354 sq ft (33.54 SQ) |
Between 0 and 2:12 the multiplier adds 42 sq ft or less on a 3,000 sq ft footprint, under 1.5 percent, which is why many reports and estimates use the footprint area directly for low-slope sections rather than applying a pitch factor at all.
How these measurements appear in the report
A report on a low-slope structure usually separates the flat or low-slope section from any steep-slope section on the same building, which matters on mixed roofs, a hip-and-gable house with a flat rear addition, or a commercial building with a pitched mansard over a flat field.
Area and perimeter appear in the summary the same way they do on a pitched roof: total squares, total square feet, and total linear feet of perimeter.
Parapet walls get their own line: linear footage plus a noted height, often banded into ranges such as under 18 in, 18 to 24 in, and over 24 in, since flashing height changes both material take-off and labor time.
Drains, scuppers, and penetrations are listed as counts. Penetrations are frequently grouped by size class, for example pipe boots under 3 in diameter versus over 3 in, and equipment curbs listed by their own footprint, because each size class prices differently in the estimate.
Line items these measurements drive
Once the figures are in hand, each one maps to a specific line item category. The pairing below is generic; confirm exact code selections against your price list and Xactimate® or Symbility® documentation, since categories and pricing structures vary by version.
| Measurement | What it drives | Typical line item |
|---|---|---|
| Roof area (SQ) | Tear-off and new membrane quantity | Tear off and haul low-slope roofing, per square; new membrane install, per square |
| Perimeter (LF) | Edge treatment where there is no parapet | Metal edge or gravel stop, per LF |
| Parapet length and height (LF) | Coping cap and wall flashing quantity | Parapet coping cap, per LF; base flashing, per LF |
| Drains and scuppers (count) | Drain hardware replacement or resealing | Roof drain, each; scupper, each |
| Penetrations (count by size) | Pipe boot, vent flashing, and curb flashing quantity | Pipe jack flashing, each; equipment curb flashing, each |
Ordering measurements for a flat or low-slope roof
Flat and low-slope roofs are ordered the same way as pitched roofs, by property address, with delivery as ESX for Xactimate®, XML for Symbility®, or PDF. You can order a roof report by address from the site sponsor, Sketch My Roof, and the published residential menu applies: Standard ESX $19, Complex-roof ESX $25, PDF-only $25, ESX + PDF $29, with no subscription and no minimum.
When the parapet is a major part of the structure, a dedicated wall product may be worth ordering alongside the roof report so parapet linear footage and height are broken out on their own. Sketch My Roof publishes Sketch My Roof roof measurement reports for walls at $45 to $65 by format for roofs under 30 SQ, with 48 hour turnaround.
Verisk™ desks can route the same order through Xactimate® Integration ordering, and files can flow into carrier-side XactAnalysis® workflows once they are in the claim system. Turnaround for the standard roof report is same calendar day for orders placed before the 6 PM Eastern cutoff.
Frequently Asked Questions
Do flat roofs need a pitch multiplier applied at all?
Why is parapet height reported separately from parapet length?
Are drains counted the same way gutters are measured?
How are penetrations grouped on a low-slope report?
Can I order a flat roof measurement report the same way as a pitched roof?
Sources
- Pitch multiplier formula: square root of (rise squared plus run squared) divided by run, and resulting multipliers at stated pitches: Xactimate® official documentation (as of August 2026)
- Symbility® claim file and measurement import handling: Symbility® / CoreLogic claims documentation (as of August 2026)
- Published residential menu: Standard ESX $19, Complex ESX $25, PDF-only $25, ESX + PDF $29, no subscription, same calendar day delivery before 6 PM Eastern cutoff: Sketch My Roof residential order page (as of August 2026)
- Wall reports priced $45 to $65 by format for roofs under 30 SQ, 48 hour turnaround: Sketch My Roof walls order page (as of August 2026)
- Xactimate® Integration ordering available for Verisk™ desks: Sketch My Roof Verisk page (as of August 2026)
