How Many Screws Will I Need for my Metal Roof?

How Many Screws Will I Need for my Metal Roof?

Are you considering replacing your asphalt roof with metal roofing instead?  More and more homeowners, contractors, and commercial businesses are starting to turn to metal for their roofing needs and there’s plenty of reasons why it’s such a popular choice. 

Metal roofing is long-lasting, durable, resistant to the elements, and far more energy-efficient than asphalt roofing.  However, as with any style of roofing you need fasteners to install it properly and avoid leaks and constant upkeep.  People often get stuck trying to determine how many fasteners they need to purchase and what types to get.  This article will explain the different types of metal roofing, its benefits, how many fasteners you need, and the correct spacing and installation. 

​How to Determine the Correct Fastener Spacing & Installation
When you want to determine the exact placement and screw spacing for metal roofing there is several factors to consider.  Correctly installing your metal roof begins with using the correct tools, and that means using a screw gun and placing the screws properly.

You should attach the screws for metal roofing at both sides of the ribs on both eaves and anywhere the panels overlap.  It is recommended to place the screws on the inside flat of the panel--not on the top of the rib.  If you attach it on the top of the rib it can prevent a tight seal from forming and could cause leaks.

Attaching the screw on the rib could also cause it to tilt, stretching the screw hole until it’s bigger than the washer hole which then breaks the seal.  Rib placement could also cause the screw to pull out of the roof if the wind is high or the conditions extreme.  That’s why it’s better to fasten the screw on the inside flat area where it will easily and securely fasten to the panel.  But how many screws do you need exactly?

How Many Screws Will You Need: Two Easy Formulas 
Even if you are a beginner at roof installation if you can use a calculator, then you can easily determine how many screws for metal roofing your project will require.  There are two easy formulas to remember when determining the amount of screws you should purchase:

1. Calculate the square footage of your roof project and then multiply it by 80% (sq. footage x .80)  
2. Each 100 ft. roofing square requires 80 screws, multiply 80 by how many roofing squares you will need for your entire project

However, you will need more screws for your metal roofing installation project than just what the panels require.  The trim and panel sidelap require fasteners as well.  Here are two more easy formulas for determining how many trim screws your project needs:

1. Every lineal foot of flashing or trim will require one lap screw (a special screw for fastening together metal on metal panels where they overlap)
2. For the panel sidelap, divide the total square footage by 3 and then take that number and divide it again by 1.5

​Advantages of Using Screws Instead of Nails for Your Metal Roofing Project
Using screws instead of nails as a fastener when installing a metal roof offers several benefits.  For starters, screws just plain have better holding power than nails.  After a few years, nails can actually work themselves loose due to the roof contracting and expanding with the weather.  Screws will never work themselves loose because of their thread patterns. They also will not bend when put under intense heat like a nail does.  
Not only are screws stronger, but they also stay put better due to their threads and can be easily reversed out and replaced if necessary.  When they’re installed using a screw gun, screws are much faster than hammering a nail and actually provide better, more accurate control over placement. 

Different Types of Metal Roofing
If you are thinking about replacing your roof and installing a metal one instead then one of the first decisions you will make is which type of metal to use.  Each type has its own different aesthetic and its own different advantages.  The different types of metal roofing include:

• Aluminum: Good for both your home or a commercial setting, aluminum is an extremely light and long-lasting metal.  It also has superior corrosion and oxidation resistance.
• Copper: Considered by many to be the most aesthetically pleasing choice, people choose copper despite the higher cost due to its extreme weather and puncture resistance. 
• Tin: Using tin is the least common option, but it’s starting to become more popular as time goes on.  Homeowners who like to make an impression often choose tin over other more common roofing metals or asphalt.
• Zinc: One of the most common choices is Zinc.  Zinc actually has self-healing properties, and can even recover or ‘heal’ from damage over time and under the correct conditions. 
• Steel: Steel is both affordable and the most sustainable option for metal roofing.  It is extremely strong, easy to work with, and lasts a very long time. 

Benefits of Installing Metal Roofing
Businesses and homeowners who install metal roofing choose it for a reason!  There are a variety of advantages and benefits to having metal roofing as opposed to asphalt or any other kind of roofing. 

• Durable: Metal is extremely durable and can last up to 50 years as opposed to 10 or 20 with traditional asphalt roofing. 
• Better for the Environment: Metal is the most environmentally sustainable option for roofing.
• Low Maintenance: Since it’s so durable and strong, metal requires almost zero upkeep in the years after its installation. 
• Weather and Sun Resistance:  The sun can cause asphalt roofing to fade over time.  Metal fades less and can withstand harsh climates or the sun’s UV rays with minimal damage. 
• Superior Insulation: Due to it’s insulating properties, installing a metal roof can actually decrease your energy bill by 10-15%!  Insurance companies might even give you a discount on your policy.

 
What Other Materials Will You Need?
Before you start installing your metal roof, you want to make sure you have a few other products and tools that you’ll need to properly complete everything.  Here are a few different products recommended when using screws for metal roofing, including:

1. Hardening foam for the edges of the eaves and valleys
2. Vented or non-vented ridge foam
3. Panel fasteners (screws)
4. Ice and water shields for colder climates and nails to install them
5. Trim screws, rivets, and flashing
6. Hand benders and a pair of tin snips, preferably extremely sharp for ease in cutting
7. Sealant for the roof, such as caulk
8. Touch-up paint to finish off the final cosmetic details

Final Thoughts on Metal Roofing and Determining Which Materials You Will Need
Metal roofing is an excellent option for just about any roofing project you may come across, whether it’s for a house, shed, or even a commercial application.  Screws are usually the best fastener to use when installing a roof no matter what type of metal or application.  As long as you follow the proper installation instructions and place the screws on the flat of the panel, you will end up with a long lasting, virtually leak-proof and environmentally sustainable roof that can also save you money on your energy bills.  It’s no wonder so many homeowners are making the switch from asphalt to metal!