Metal roofing over shingle is a traditional way of increasing your roof’s longevity, repairing the old damage problems, handling heat control, and many more. 

Hence, how to install metal roofing over shingles is a common question among house owners and roofers. Well, there are a couple of ways to do so. One is to put underlayment over shingles and apply metal sheets directly on top of that.

The other way is to put a frame between the underlayment on top of shingles and the metal sheets. The latter is most preferable for its benefits such as longevity, a unique base for sheets, and many more.

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Let’s discuss the steps that you have to follow throughout the whole installation procedure.

How To Install Metal Roofing Over Shingles: step by step process

Placing metal roofing over your shingles is not simple work, rather it is a complex, step-by-step process. But if you follow these couple of steps properly, the installation will be a little easy and enjoyable. 

Steps To Follow:

Step 1: Cleaning of the shingles

Cleaning the shingles is very important before starting any renovation or installation plan on your roof. Cleaning shingles can be done only using water pipes and applying directly to the shingles. Sometimes a brush or something may be needed to rub off the dust or any other particle from the shingles.

Step 2: Installation of Solar Reflector

After cleaning the shingles, make sure to install a solar reflector underlayment. The solar reflector creates a good barrier for UV rays and keeps out most of the heat out of your attic. 

This stuff functions like felt paper. And the installation procedure is the same as the felt paper. You need to start from the bottom and work your way up. 

Two rows of nailing are recommended for attaching the reflector. One is closer together with an equidistant nailing pattern on the bottom. After that, keep one foot or more gap between the bottom and middle line.

Sometimes the nailing pattern can overlap. This reflector also works as insulation and waterproofing of the roof. 

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Step 3: Make measurement

The next thing is to make the measurements of the roof. This can be done in two ways.

Firstly, you have to climb up to your attic, have the calculations and transfer the values according to the roof. Secondly, you need to climb up to your roof and then have the measurements by yourself, or with the help from others.

Step 4: Prepare the truss and furring strips

Now, it is time for the preparation of the truss or the main framework for the metal roofing. The angles and other factors of roofing should be kept in mind while doing the framing.

Popping a line in every two feet is one of the easiest ways to check the angles while doing the framing. According to the line, the frame is prepared by attaching wooden or timber poles. 

This can also be done with the help of some two feet block instead of using exact tape measurements or popping lines. Make sure to attach the base of the frame very firmly, so that it can support the metals above it.

A furring strip system is usually made by 1 out of 4 where the workers bring the deck out. They put the furring strips down at the desired foot spacing, and attach the metal panels directly to that.   

Step 5: Putting the metals

After the first inspection, that all the frames and everything are alright and ready to go, the next thing is putting the metals. You can start the metal plotting from the valleys, as it is one of the crucial points in roofs for water leaking. 

Cutting metal sheets for the valley is not very hard, but it is not very easy either. For the metal, you can pre-drill the screw holes. It can make your work much easier and fast.

Or you can drill the screw holes on the metal sheets and at the same time connect the sheets to the truss.

While nailing, check whether the screws are equidistant or not, and whether the screw holes are properly sealed or not. Screw improper sealing can permanently damage the roof.

You can attach first the two endpoints of the sheets and try to drill the entire sheet afterward. This ensures the straight placing of the metal sheets. It is always encouraged to check for overlapping parts when you are drilling the sheets. 

Step 6: Check for roof angles

Sometimes, a jig is made for handling roofing angles. Two four feet pieces of 1*4 are attached with roofing screws at one part. After that, the other part is also secured with the screws. 

Lastly, check for your ridge cap to be set properly. The ridge cap mainly stands on the merging point of two sides of the roof’s metal sheets.

It can be slightly higher than the other two sides of the roof. A slight pitch can handle the roofing very efficiently making it directly go down the valley. Secure the ridge with roof sealant.

Step 7: Final inspection

Now, you have to check for the screws, drilling of holes, sealing of screws, the overlapping areas, the ridge cap finishing for the last time. Make sure the water sealing is working properly along with the solar reflection.

It is said that after using the solar reflector, the usage of air conditioning in a home is drastically reduced.

Considerations before installation of metal roofs over shingles

The first thing that you have to consider is how your metal roof is going to be attached. 

Again, when you are creating furring strips and things like that, panels are going to follow the roof deck and roof plane. So, if there are any imperfections on the deck or in the roof plane, it will adversely affect your work.

Usually, furring strips are installed rake to rake, and the typical airflow is eave to ridge. You may be doing that and you are thinking you are getting good ventilation, but you are probably not.

The real way to do it is to do a cross-hatch. So you have some going on both horizontally and vertically. Thus, proper ventilation can be allowed.

Benefits of metal roofing over the shingles

Although it may seem that by directly applying metal sheets over shingles, you can save time, energy, and money up-front. But you can be potentially facing some aesthetic issues or situations. The roof may not be adequately vented, condensation issues, trapping moisture, and many more. 

Metal roofing also has cool roofing properties. So, while the metal roofing panel might cool off faster as the sun goes down, the shingles directly attached to it are going to retain the heat. And it will take quite some time for those shingles to dissipate the heat than the metal roof.  

Final Words

Now, don’t you think you have an idea of how to install metal roofing over shingles? I hope you do.

If you have any queries regarding the matter, search for it on google or consult a professional.
However, always make sure that the water sealing, air breathability is working properly in your renovated system. Otherwise, the roof will eventually get damaged and will have a short span of life.

Author

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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