Can You Lay Metal Roofing Over Shingles? | Expert Guide & Tips
Yes, you can put metal roofing over shingles, and many homeowners and builders are doing it now. Installing metal roofing over existing asphalt shingles saves time and money because you do not have to remove the old shingles. First, you need to check the roof for damage, make sure it can hold the weight of metal panels, and prepare the roof deck with underlayment, furring strips, or other systems. This ensures the roof lasts a long time. You can use different types of metal roofing like standing seam panels, stone-coated metal roofs, metal shake roofing, or metal tile roofing. Metal roofs last much longer than asphalt shingles, usually 40 to 70 years compared to 12 to 20 years, and they look modern and stylish.
Benefits of Installing Metal Roofing Over Existing Shingles
Putting metal roofing over existing shingles has many benefits. It saves money because you do not have to tear off old shingles or pay for disposal. Metal panels, including corrugated sheets, standing seam panels, or metal shingle roofing, are very strong and resist fire, pests, hail, heavy rain, snow, and high winds. Metal roofs also save energy by reflecting the sun’s heat and reducing cooling costs, and they work well with solar panels. They are often made from recycled materials, are 100% recyclable, and help reduce landfill waste. Metal roofs also look clean and modern, with many styles and colors to choose from, including metal tile or metal shake roofing.
Table of Contents
- Can You Lay Metal Roofing Over Shingles? | Expert Guide & Tips
- Benefits of Installing Metal Roofing Over Existing Shingles
- Understanding Roof-Over: When and Why It’s Possible
- Step-by-Step Preparation for a Metal Roof Over Shingles
- Methods for Installing Metal Roofing Over Shingles
- Pros and Cons of Roof-Over Metal Roofing
- Maintenance Tips for Metal Roofs Installed Over Shingles
- Common Mistakes to Avoid When Installing Metal Over Shingles
Understanding Roof-Over: When and Why It’s Possible
A roof-over is when you put metal roofing on top of shingles. This works well if local building codes allow it and the roof can hold the weight. The old shingles should be in good shape with no cracks, curling, or missing pieces. The roof deck might need repairs for rot, leaks, or weak spots. Systems like shingle recover systems with above sheathing ventilation (ASV) help air flow under the metal roof, keeping moisture and mold away. Roof-over is a good choice if the roof is still strong and you want to save money, but sometimes a full roof replacement is better if the roof is very old or damaged.
Step-by-Step Preparation for a Metal Roof Over Shingles
Before installing metal roofing over shingles, proper preparation is very important. First, check the old shingles for cracks, curling, or missing pieces, and fix or replace them if needed. Clean off dirt, moss, and debris. Make sure the roof structure can hold the metal panels. Gather materials like underlayment (#30 felt, synthetic underlayment, or thin foil-faced insulation) and tools like metal snips, a circular saw with a metal-cutting blade, roofing screws with rubber washers, a staple gun, tape measure, roofing tape, caulking, ladder, harness, and protective gear. Finally, follow local building codes and make sure the roof-over system you choose, like furring strips or direct attachment, meets both legal and performance standards. Good preparation makes the roof installation easier and longer-lasting.
Methods for Installing Metal Roofing Over Shingles
There are several ways to install metal roofing over shingles. One method is to attach metal panels into furring or lathing strips, also called wood purlins or sub-girts. This creates a flat surface and allows air to flow under the roof. Another method is to attach panels directly into the shingles if the roof deck is in good shape. Shingle recover systems can also be used to add above sheathing ventilation (ASV) to keep the roof dry. No matter the method, it is important to measure carefully, cut panels to the right size, overlap them for a watertight seal, and secure them with screws through the ridges. Flashing should be installed around chimneys, vents, skylights, and edges, and ridge caps should be added to finish the roof.
Pros and Cons of Roof-Over Metal Roofing
Roof-over metal roofing has many advantages. It is faster and cheaper than removing old shingles. Metal roofs are very strong, resisting wind, hail, heavy snow, and fire. They last longer than asphalt shingles, save energy, and can support solar panels. They also look modern and attractive. But there are some things to think about. Uneven shingles may show through the metal panels. Proper ventilation is needed to prevent moisture and mold. Metal roofs can be noisier during rain or hail, but symmetrical panels are easier to repair.
Maintenance Tips for Metal Roofs Installed Over Shingles
Metal roofs over shingles are easy to maintain, but regular care is needed. Check for loose screws, damaged panels, or problems with flashing. Keep the roof clean from debris and make sure ventilation is working to prevent ice dams, mold, and moisture buildup. Fix scratches or minor damage quickly to prevent rust. Clean gutters so water can drain properly. Symmetrical panels are easier to repair, and regular checking of ridge caps, flashing, and clip design systems will keep the roof strong and lasting for decades.
Common Mistakes to Avoid When Installing Metal Over Shingles
Some mistakes can cause problems with metal roofs over shingles. Not checking or fixing the old roof deck can make panels fail faster. Skipping proper underlayment, furring strips, or ASV can lead to moisture, mold, or ice problems. Cutting panels wrong or overlapping them incorrectly can cause leaks. Not securing panels with screws through the ridges lowers wind resistance. Flashing and ridge caps must be installed carefully around chimneys, vents, skylights, and edges. Weather conditions should be right during installation, and local building codes about roof layers must be followed to keep the roof safe and strong.