Is your energy bill giving you a headache each month? Your flat roof might be part of the problem.
Old-style flat roofs soak up heat like a sponge, making your air conditioner work harder than it should. But there’s good news – you have options that can turn your roof from a problem into a helper.
Metal roofing has come a long way in recent years, with new designs for all kinds of buildings. While metal can work on flat roofs, let’s look at all your options to find what’s best for you.
What is Considered a Flat Roof?
Ever notice how some buildings seem to have no roof slope at all? These “flat roofs” aren’t actually flat!
Typically rising only 1/4 to 1/2 inch per foot, they’re barely noticeable to the eye.
Flat roofs are everywhere once you start looking: city buildings, modern homes, and additions like garages. People choose them to create outdoor living space, make AC installation easier, save on building costs, and achieve that clean, modern look.
While they appear level from the street, that subtle tilt is crucial. Without it, water would pool on top, eventually finding weak spots and causing leaks. So remember—in roofing, even “flat” has a little angle to it!
Can Metal Be Used on a Flat Roof?
Many people don’t know this, but today’s metal roofing can handle low slopes, just not flat roofs.
The key is choosing the right type. Standing seam metal roofs have raised edges that sit above water, creating paths for rain to flow away. The panels lock together without exposed screws, keeping water out.
Metal roofs offer several benefits: they last a long time, reflect sunlight to keep buildings cooler, stand up to storms, and need little upkeep. When they wear out (decades later), they can be recycled!
However, while metal is an option for low slopes, at Mangold Roofing, we’ve found that TPO (Thermoplastic Polyolefin) roofing usually works better for flat roofs. TPO creates a seamless waterproof surface and offers similar energy benefits at a better price.
TPO: Mangold’s Recommended Solution for Flat Roofs
At Mangold Roofing, we recommend TPO (Thermoplastic Polyolefin) as the best choice for flat roofs for these reasons:
- Creates a seamless, watertight surface perfect for flat roofs.
- Reflects heat just like metal, keeping your building cool.
- Costs less than metal roofing.
- Made specifically for flat and low-slope roofs.
- Flexes with your building as it settles or shifts.
- Easier and quicker to install properly.
- Handles very low slopes better than metal options.
TPO roofing has become our go-to solution for flat roofs because it solves the unique challenges these roofs face without the drawbacks of metal in very flat applications.
Minimum Slope (or Pitch) for Metal Roofing
Even “flat” roofs need some slope, and metal roofing has specific requirements to work properly. Most metal roof systems need at least a 1/4 inch rise for every foot of roof—what pros call a “1:48 slope” or “1/4:12 pitch.”
Standing seam metal roofs (the kind with raised seams) typically need a bit more slope—about 1/2 inch per foot minimum. Some manufacturers have special systems that can work with even less slope, but you’ll want to check their warranty details.
Why does slope matter so much? Water is sneaky! Without enough slope, rain just sits there, eventually finding weak spots and causing leaks. Metal roofs with proper pitch let water flow to drains or edges.
Best Types of Metal Roofing for Low Slope Roofs
When picking metal roofing for low slope roofs, here are your best options:
Standing seam metal roofing
The raised seams keep water out! Look for mechanically seamed versions where the panels lock together tightly for the best protection.
Also Read: Standing-Seam vs. Corrugated Metal Roofs
Aluminum roofing
It won’t rust and is very lightweight. Perfect if you live near the ocean or if your building needs a lighter material.
Steel roofing
It is strong, durable, and more affordable. Just ensure it has a good coating to prevent rust when it rains.
Zinc or copper roofs
They become more beautiful with age, developing unique colors over time. They last for decades with minimal maintenance.
Insulated metal panels
It protects your roof while adding insulation to keep your building comfortable year-round.
Pros & Cons of Using Metal Roofing on a Low Slope Roof
Pros of Using Metal Roofing on a Low Slope Roof
Built to last
Metal roofs can protect your building for 40-70 years, far longer than other options, making them worth the extra money up front.
Hassle-free upkeep
Say goodbye to constant repairs! Metal roofs only need occasional check-ups and simple cleaning to stay in great shape.
Weather warrior
These tough roofs stand strong against fierce winds, heavy snow, and even fire, which might lower your insurance costs too.
Cooler summers
The shiny surface bounces heat away instead of soaking it up, keeping your building cooler and cutting down on air conditioning bills.
Planet-friendly pick
Made from recycled materials and completely recyclable later, metal roofing helps reduce construction waste and environmental impact.
Challenges to Be Aware Of:
Costs more upfront
You’ll pay more initially than for traditional flat roof materials, though the longer lifespan makes up for it over time.
Needs pro installation
Hiring experts is a must, as mistakes during installation can lead to leaks and headaches that defeat the purpose.
Expands in heat
Metal stretches when hot and shrinks when cold, requiring special installation techniques to prevent problems down the road.
Requires a slight slope
Completely flat roofs need extra waterproofing systems, as metal roofing works best with at least a gentle slope for drainage.
Not ideal for very flat roofs
While metal can work, TPO often performs better on very flat roofs.
Maintenance Tips for Metal Roofs
While metal roofs are low-maintenance, a little regular care goes a long way in protecting your investment. Here are some simple ways to keep your metal roof in top shape:
- Check your roof after big storms or heavy winds to catch small problems before they turn into expensive repairs.
- Keep drains, gutters, and scuppers free of leaves and debris to prevent water from pooling, which can lead to leaks and damage.
- Regularly look for loose fasteners, worn sealant, or damaged flashing, as these are common spots where water can sneak in.
- Consider signing up for annual maintenance with roofing professionals who know what to look for and can spot issues you might miss.
- Pay special attention to seams and joints where different roof sections meet, as these vulnerable areas often develop problems first.
- Address scratches or coating damage quickly with appropriate touch-up materials to prevent rust and extend your roof’s life.
Wrapping Up…
While metal roofing can work on low slope roofs with proper installation, our experience at Mangold Roofing shows that TPO roofing usually works better for truly flat roofs.
Whatever you choose, proper installation is essential. You need experienced pros who understand flat roofing challenges.
Want the best results?
Mangold Roofing’s experts can look at your specific situation and recommend the ideal solution. Call us today!
