Have you ever thought about the possibility of leakage in your roof? Well, if you fasten the metal roofing properly, there should not be any leaks in your roof. Hence, you might wonder about how to fasten metal roofing.

Fastening a metal roof is one of the simplest parts of metal roofing installation. You can simply drive in screws to fasten a metal roof. 

However, not knowing the proper procedure will make the process unnecessarily complicated. Moreover, you will have problems like leakage down the line.

Hence, it is important for you to know about the process of fastening metal roofs. Let us elaborate on the whole process step by step so that you can seamlessly learn about the procedure.

How To Fasten Metal Roofing

Fastening metal roofing is quite a straightforward procedure. You just need to be cautious about a few things. To get started, you will need some tools and materials. Once you have collected them, you can start with the procedure of fastening metal roofing.

Necessary Tools and Materials

  • Screw Gun
  • Screws
  • Rubber washer 
  • Metal Cap
  • Soft-bristled broom
  • Chalk 
  • Measuring tape
  • Hammer
  • Chalk line clips and strings
  • Measuring Tape

Step By Step Procedure

Step 1: Chalk Lining the Roof

The first step is to draw a chalk line over the roof. Chalk lining your roof will give you straight lines and intervals at a definite distance to drill your roof. 

Using a measuring tape, you can draw chalk lines. You will also need other tools like chalk, chalk line clips, strings, hammer and nails. 

However, you must remember to clean the chalk lines after you’ve completed the task. You can easily clean the chalk lining using a clean rug. However, do not wait for rainwater to wash off the chalk lines.

In many cases, rainwater cannot completely wash off chalk lining from your roof. If you do not clean the chalk lining, your roof will lose its beauty over time. 

Step 2: Pre-drilling Screw Holes

After you have completed chalk lining your roof, you should move on to the next step. You should pre-drill screw holes in your metal roof. The screws used to fasten the metal roof are self-drilling. That means, these screws can make holes in the metal roof on their own. 

However, pre-drilling screw holes have some perks. Firstly, it will save a considerable amount of time. Secondly, you will be able to drill the holes at the correct interval. Thirdly, it will be easy for you to navigate the screws while fastening the metal roof.

But, in some cases, pre-drilling the metal roof can cause problems. For instance, when you install metal roofing over metal purlins, it might be tricky for you to pre-drill holes.

However, in case you are fastening the metal roofing to a wood substrate, there shouldn’t be any problems with pre-drilling the holes. It would be best to seek advice from professionals regarding this case.

Step 3: Installing Metal Screws

Upon completion of the previous step, you should get started with the next one. Firstly, get a screw gun and the screws. Each screw should have a metal cap along with a rubber washer. The rubber washer is a little smaller than the metal cap. Following that, get a screw gun to install the screws.

Using a screw gun, you should start the installation process. It is essential to drill the screw in properly. Now, put the metal cap into the screw gun and place it over a hole. Following that, start driving in the screw. 

When you see that the rubber washer is just at the edge of the metal cap, stop drilling. In a similar manner, drive all the other screws into your metal roofing.

Step 4: Checking the Fastened Roof

You should now check the screws that are fastening your metal roof. You can understand whether you’ve installed the screw properly by checking a few things like:

i) Over-tightening the Screw:

You may sometimes over-tighten the screw. You can understand it just by simple observation. 

When you drive the screw too far, the rubber washer below the metal cap will overstretch. This may cause the rubber washers to break. Even if the washers do not break right after tightening, they will break or leak quite early.

Once you notice that the screws are overtightened, you should release some pressure and tighten those properly.

ii) Under-tightening the screw: 

It is pretty common to under-tighten the screw. You can easily determine whether the screw is loose or not just by spinning the washer. 

In case the washer spins, you should re-tighten the screw with the help of a screw gun. However, if the washer does not spin, the screw is properly tightened.

iii) Installing Screws sideways:

The screws should always be screwed in a straight position. In case the screws are installed tilted or sideways, the rubber washers will not tighten properly. That will cause leakage in the roof.

In case you notice anything like that, you should reinstall the screws straight.

Step 5: Cleaning the Roof

After you’ve fastened the metal roof, you should take a soft-bristled broom or brush. You will see metal shavings around the places you have drilled in the screws. Clean the metal shavings with the broom or brush.

Not cleaning the metal shavings will cause the formation of corrosion spots. It may even permanently stain your metal roof. Hence, you must clean the metal shavings off your roof.

Frequently Asked Questions 

1. What is the proper way to screw down metal roofing?

Ans: The proper way to screw down metal roofing is by putting the screws in the flat.

2. What is the screw pattern for metal roofing?

Ans: Lap screws are generally spaced 12” to 18” in the center. The panel screws are evenly spaced out.

3. Why do screws back out on metal roofs?

Ans: Screws generally back out on metal roofs because of temperature variation. In summer, metal roofs expand. Contrarily, in winter metal roofs contract. This phenomenon causes the screws to back out on metal roofs.


Fastening a metal roof is a simple process. We have tried to explain the process as elaborately as possible. We hope that you have understood all about

How To Fasten Metal Roofing

However, you can always hire professionals in case you are unsure about doing it yourself. But, if you decide on fastening the metal roof yourself, you should not encounter any problems.

You can also ask for help from your friends or neighbors. Always remember to use proper precautions and maintain safety protocols. Thus, you should not run into any problems. 


As a civil engineer and roofer, I love to share the experience that I have gained through the last couple of years. In the roofing industry, practical experience is a very crucial fact that can help you a lot. Hence, I want to help you with my blog.

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