How to Install Metal Roofing Over Shingles?

by | Jan 3, 2024

Thinking about making your roof better without a big hassle? How about putting a metal roof over your shingles? Before you start, check if your roof is ready for this change. It’s smart because many roofs need fixing. In this article, we’ll guide you on how to do it step by step. Just remember to check the local rules – some places say only two layers are okay before you need to redo everything. This way, you save money, time, and avoid extra problems. Improve your roof without a big fuss – we’ll show you how!

What to do before deciding to install metal roof over shingles?

Assessing Shingle Condition

Before you begin putting in the new roof, take a good look at your existing shingles. If they’re messed up or starting to curl, you need to either remove them or install lathing boards before adding the new metal roof. Make sure the roof deck is in good condition to give a strong foundation. Usually, local rules only allow two layers of roofing, so make sure to follow your area’s regulations.

Checking Your Roof

Take a good look at your roof for any fire, water, hail, or other damage. If you spot any issues, fix them right away by replacing the broken parts. This ensures your roof can handle the new metal one. Skipping this step could cause some serious problems down the road.

Checking the Strength

Think about how heavy the new roof will be. Even though metal roofs are usually lighter (fun fact: on average, a metal roof is 50% lighter than an asphalt shingle roof and a whopping 75% lighter than concrete tile, fiber cement shakes, and slate), it’s crucial to make sure your roof can handle the extra weight. If your roof wasn’t built to handle that weight, it might start to sag or break. Chat with a builder to get some good advice.

Step-by-Step Guide: How to Put a Metal Roof Over Shingles

Method 1: Attaching Metal Panels into Furring or Lathing Strips

Installing Wood Furring Strips

Before you start laying down those metal panels, the first big move is getting those wood furring strips or spacers in place. These strips do a crucial job—they create a little gap between your metal panels and the shingles already on your roof. Why? Well, when the temperatures start playing tricks, and things expand and contract, we want to avoid any rough business. Those wood strips prevent the abrasive texture of the shingles from scratching off the primer on your shiny new metal roof. It’s not just about durability; it’s about keeping things looking good too.

Using MWI’s Labor Saver

Now, let’s talk about working smart. If you’re looking to boost efficiency, get your hands on tools like MWI’s Labor Saver. It’s like having a trusty sidekick—lightweight but tough, specifically built for redoing roofs. The idea? Make installing those metal roofing panels a breeze. Less sweat, more streamlined work. With the Labor Saver in your toolkit, you’re not just saving time and energy; you’re making the whole installation smoother.

Thinking Green—Environmental Considerations

While wood furring strips are a go-to for creating that necessary gap, let’s think long term. Wood can get a bit moody with time, especially with corrosion. That’s where the eco-friendly angle comes in. Consider alternatives, like the Labor Saver. It’s lighter, won’t rust, and easier to stash away. Making choices like these isn’t just about getting the job done; it’s about doing it sustainably. Your metal roof will thank you for it, and so will the environment.

Method 2: Attaching Metal Panels Directly into Shingles

Connecting Through Shingles

Now, here’s a budget-friendly move. We’re talking about hooking those metal panels right through your existing shingles and into the wood deck below. No furring strips, no spacers—just a straightforward, maybe more wallet-friendly method. But, and there’s always a but, let’s talk about how this might play out over time for the look and performance of your metal roof.

Ventilation Hurdles

The catch with this direct attachment trick is getting the ventilation game right. We’re aiming for something called Above Sheathing Ventilation (ASV). That’s like giving your roof the space to breathe, regulating temperatures and keeping things cool. Without those furring strips creating a gap between the metal panels and the shingles, we’re up against a ventilation challenge. It’s a bit trickier, especially if you’re in a spot where keeping the temperature in check is a big deal.

Gotta Have a Barrier

To keep things smooth over the long haul, you’re gonna need a shield between the old shingles and your brand-new metal roof. This barrier isn’t just for looks; it’s a guard against wear and tear. Think #30 felt, synthetic underlayment, or a thin foil-faced insulation. They act as bodyguards, stopping the abrasive texture of shingles from wearing down your metal panels as they expand and contract with the changing temperatures. It’s like armor for your metal roof.

Pros and Cons of Metal Roofs

AspectMetal RoofsShingles
Longevity           50+ years with minimal maintenance               Typically 20 to 30 years
Aesthetics         Variety of styles and colors         Limited options, prone to wear
Environmental Impact Made from recycled material     Shingles are rarely recycled, high disposal fees
Upfront Cost     Higher cost initially.         Putting up a metal roof on a 1,700-square-foot roof averages around $13,200.  Lower initial cost, frequent replacement

Wrapping Up

So, in the end, fixing a metal roof over shingles needs good planning. You gotta check if the old shingles are okay, look at the roof base, and make sure the structure is strong. Our step-by-step guide talks about two ways to do it, each with its own good things and stuff to think about. The table shows what’s good and not-so-good about metal roofs – they last long, look nice, and are good for the Earth. Sure, they cost a bit more at the start, but being tough and Earth-friendly makes it a smart choice for the long run.

Thinking about it? Get a free quote for your metal roof at Best In The West. They know what they’re doing and can help you out.