Built-Up Roofing vs Asphalt Shingles for Minnesota Commercial Properties

Choosing a roofing system for a commercial building isn't the same decision as picking shingles for a house. Flat or low-slope roofs need different materials, and Minnesota winters add another layer to that math. This breakdown covers how built-up roofing and asphalt shingles compare on cost, durability, and fit for commercial work in this state.

What Is Built-Up Roofing?

Built-up roofing, often called BUR or a "tar and gravel" roof, is one of the oldest commercial roofing systems around. Installers layer alternating plies of bitumen and reinforcing fabric, then finish the top with gravel or a cap sheet. The result is a thick, heavy membrane that handles standing water well.

BUR works on low-slope or flat commercial roofs, which are common on strip malls, warehouses, office buildings, and retail spaces across Minnesota. It's not a system you'd put on a steep residential pitch.

What Are Asphalt Shingles on a Commercial Roof?

Asphalt shingles are almost always a residential product, but you'll find them on some commercial buildings with steeper roof pitches. A church, a small professional office, or a storefront built to look like a house might have shingles instead of a membrane system.

If your commercial building has a pitch of 4:12 or steeper, shingles are a realistic option. Below that slope, water doesn't drain fast enough and shingles will fail early. Most flat-roofed commercial buildings in Minnesota aren't candidates for shingles at all.

How Minnesota's Climate Affects Both Systems

Minnesota puts roofs through a lot. Freeze-thaw cycles, heavy snow loads, ice damming, and the occasional severe summer storm all wear on roofing materials in different ways.

BUR handles the cold well. The multiple layers give it flexibility under temperature swings, and the gravel surface reflects some heat in summer. The weak point is the seams and flashings. When those aren't installed right, water finds a way in during spring thaw.

Asphalt shingles on a steep commercial roof hold up fine in Minnesota when they're properly ventilated. Ice dams are the main concern. Poor attic venting causes heat to escape through the deck, melts snow from below, and refreezes at the eaves. That ice backs up under shingles and causes leaks. Proper attic venting solves most of that problem before it starts.

Cost Comparison

BUR typically costs more upfront than shingles. A basic BUR system on a flat commercial roof runs higher per square foot because of the labor-intensive layering process and the weight of materials. You're also looking at more specialized equipment on the job site.

Asphalt shingles cost less per square to install. But the comparison only matters if your roof pitch actually allows shingles. If you have a flat or low-slope roof, shingles aren't on the table regardless of price.

On lifespan, a well-maintained BUR roof lasts 20 to 30 years. Quality architectural shingles on a steep commercial roof last 25 to 30 years with proper care. The gap in longevity is smaller than most people expect.

Maintenance and Repair Differences

BUR needs regular inspections, especially around drains, flashings, and penetrations like HVAC curbs. Gravel can hide damage, which means small problems go unnoticed until they turn into bigger ones. Scheduling a commercial roof inspection once or twice a year keeps minor issues from becoming costly repairs.

Shingles are easier to inspect visually. A contractor can spot cracked, missing, or lifted shingles from the ground or a ladder. Repairs are straightforward because damaged shingles are replaced individually. The tradeoff is that storm damage tends to show up more on shingles, and a bad hailstorm can mean replacing a large section all at once.

Both systems need good flashing work. Flashing around chimneys, vents, parapet walls, and skylights is where most commercial roof leaks start. Getting that right during installation prevents most of the headaches down the road.

Which System Is Right for Your Building?

The roof's pitch makes most of the decision for you. Flat or low-slope roof? BUR is the right category to be shopping in. Steep pitch? Asphalt shingles are worth pricing out.

Beyond pitch, think about your building's use. A warehouse that takes a lot of foot traffic for HVAC maintenance does better with a durable membrane. A professional office building with a steep gable roof might look better and perform just as well with architectural shingles.

Budget matters too. If cash flow is a concern, commercial roofing financing options exist that let you spread the cost of a full roof replacement instead of putting it all out at once.

When you're not sure which direction to go, a roof inspection by an experienced contractor gives you the information you need without committing to anything.

If your commercial property needs a new roof and you're not sure which system fits, get a professional opinion before you commit to materials. Roofs Direct has worked on commercial roofing across Minnesota for over 28 years. Schedule a free roof inspection and you'll get a straight answer about what your building actually needs.