When making modifications or improvements to your home, there are many factors that must be considered. One of the more important of these is the weight limit of your roof. A given structure can only hold so much weight, and this limit can vary a lot from building to building. So, for those of you who want to make sure your roof doesn’t collapse, let’s consider the best way to calculate the weight of metal roofing.
Calculating The Weight Of Your Material
There are many different types of metal roofing, but weight is largely a matter of material. Thus, we can easily figure out the weight of a piece of roofing metal. To save some time, let’s take advantage of this handy online calculator. Here, we can input the length, width, shape, and thickness of our metal and obtain an accurate result in pounds.
Let’s start with aluminum, as it will most likely be the lightest. We know that we are working with flat pieces here, but we need to figure out how thick a standard piece of roofing metal will be. Based on what we can find (and most online sources), it seems that that the standard thickness is 0.36 mm, which equals 0.014 inches. This thickness is also described as “29-gauge” if you prefer that scale. If you want something a little thicker, many companies also make 26-gauge roofing panels, which translates to 0.48 millimeters or 0.018 inches.
How Much Does Each Roofing Material Weigh?
Using the online calculator linked above, we will calculate the weights of the most common roofing metals. For these calculations, we will assume a length of 1 foot and an identical width. We will also use the standard thickness of 0.37 mm. This will allow us to figure out the weight-per-foot ratio of each metal.
- A 1×1 piece of flat aluminum weighs: 0.20 lbs per foot
- A 1×1 piece of flat steel weighs: 0.57 lbs per foot
- A 1×1 piece of flat stainless steel weighs: 0.59 lbs per foot
- A 1×1 piece of flat copper weighs: 0.66 lbs per foot
Some people might wonder why we have not included tin on this list. Contrary to popular belief, roof panels have never been made of pure tin. The material that most people call “roofing tin” is actually galvanized steel (meaning steel that has been coated with zinc). In the old days, metal roofing was made of sheet iron coated with tin, which was similar to galvanized steel. However, this kind of roofing is no longer made.
Using Our Numbers To Calculate Roof Weight
Now that we have obtained weight-per-foot figures for each metal, we can calculate the approximate weight of your metal roofing. All you have to do is get the area of your roof in square feet, then multiply that by the weight of the chosen material.
The average residential roof (in the United States, anyway) is about 17,000 square feet. So, let’s plug our numbers into the calculator and see what we get.
- Aluminum: 0.20 pounds per foot X 17,000 feet = 3,400 lbs
- Steel: 0.57 pounds per foot X 17,000 feet = 9,690 lbs
- Stainless Steel: 0.59 pounds per foot X 17,000 feet = 10,030 lbs
- Copper: 0.66 pounds per foot X 17,000 feet = 11,220 lbs
The square footage of your roof is unlikely to be exactly 17,000 feet. That is an average number, so take it as such. If you don’t know how to calculate the area of your roof, here’s another handy online calculator that will help you. Once you have that number, just multiply it by the weight per foot of your material, and you will have a pretty accurate measurement.
Interpreting The Results
It might surprise you to see that copper is heavier than steel. However, it does seem to be significantly heavier than steel, which might explain why copper roofing isn’t all that common. People will often use copper flashing for its decorative effect, but very few will opt for an all-copper roof. This is both because of its higher cost and its greater weight.
Aluminum is obviously the superior choice for a metal roof, simply because it will resist corrosion more effectively than steel. Not only that, but we have already seen that aluminum is a lot lighter than any of our other options. Less weight in your roofing materials means less stress on the structure of the home. Thus, lighter roof materials will keep you from shortening the lifespan of your home.
At the same time, pure aluminum roofing is a lot more expensive than coated steel. Coated steel (usually of the galvanized type) is the most common type of metal roofing because it offers a high level of effectiveness and a long lifespan without an exceptionally high cost. Ordinarily, steel would not be a good roofing material due to its tendency to rust. However, roofing steel is coated with other metals like zinc or aluminum, giving it much better resistance against the elements.
The only problem with metal plating is that it will eventually wear away. Once that happens, the surface of the steel will be vulnerable to corrosion, and will eventually need to be replaced. Still, that’s not such a big deal when you consider the relatively low cost of roofing steel.
As a final note, we should mention that there will be a little bit of overlap. These pieces of metal will need to overlap slightly, much as shingles do, and that means that you will lose a little bit of square footage. The difference shouldn’t be too large, but you should be aware that these calculations are likely to be just a little bit on the low side.
Calculating the weight of a roof is never an easy task. After all, it’s not like you can just pull the roof off the house and put it on a scale. Instead, you have to use a little math, and there’s no way around that need. Still, we hope that we have made the whole thing as simple as possible. For those who want to learn more about professional roofing services in your area, make sure to fill out the contact form.