# BUR vs. Single-Ply: How to Choose a Commercial Roof System

## Short answer

A **built-up roof (BUR)** assembles waterproofing from multiple field-installed plies of felt bonded in bitumen — redundant layers. A **single-ply membrane** is factory-fabricated and installed as one layer with welded laps. BUR buys redundancy; single-ply buys speed, lighter deck loading and lower first cost.

Over a twenty-year hold, the cheaper roof is the one that doesn't leak.

## Comparison

| Consideration | Built-Up Roofing | Single Ply |
|---|---|---|
| Layers of waterproofing | 2–4 plies plus cap sheet | One membrane |
| Indicated service life | 10 / 15 / 20 years by ply count | Varies with membrane and thickness |
| Deck loading | Heavier | Lighter |
| Install speed | Slower — field assembled | Faster — large sheets |
| Hot work on site | Yes (hot bitumen) unless cold process | No (welded seams) |
| Puncture tolerance | High — redundant plies | Depends on membrane |
| Reflectivity | Depends on surfacing | High for TPO and PVC |
| Repair | Patch into the plies | Weld or patch; EPDM needs cleaning and priming |

## Choose single-ply when

- The roof is large, simple and low-traffic
- Deck loading is constrained
- Cooling load matters and a reflective membrane pays for itself
- The schedule cannot accommodate hot work

## Choose built-up when

- A leak means a shutdown — healthcare, institutional, campus
- The roof takes heavy foot traffic and dense rooftop equipment
- The owner holds the asset for twenty years, not five

## The third option

Modified bitumen takes the qualities of a BUR system along with the qualities of a single-ply roof: a factory-made polymer-modified sheet installed over a base sheet.

Each roofing project is unique in design and structure. Lloyd Roofing Company, Inc. provides a comprehensive assessment of every roof and recommends the system that most benefits the client in feasibility and performance.

---

**Lloyd Roofing Company, Inc.** · 2415 Montague Avenue Ext., Greenwood, SC 29649 · 1-800-421-3830 · Mon–Thu 7:00am – 5:00pm · Fri 7:00am – 12:00pm
Commercial and industrial roofing only. Serving South Carolina, North Carolina and Georgia since 1965.
SC contractor license CLG10175 · USDOT 483661