How Much Does a Roof Cost?
Updated: Sep 9, 2021
Well that depends. I know, you want a concrete answer, but there are several factors that influence the price of a roofing project including: materials selected, the pitch of the roof, how many stories your home is, and so on. An average 25 square roof should cost you between $8,750- $10,500. Let’s dissect these costs a little more so you can get a clearer idea of how much your roofing project will cost.
How big is my roof?
The first thing you need to know is that roofing professionals measure their material and labor cost based on price per square. A square in the roofing industry is equal to 100 square feet (sf) of roof surface. So 1 square = 100sf. One common misconception is that the square footage of your home equals the square footage you should calculate for your roof, but this does not take the slope of the roof into account.
To calculate the pitch of your roof you can use the following formula (slope=rise/run) or just download the pitch factor app to your phone to figure out your pitch.
Once you have your pitch you can use the base square footage of your home to calculate the estimated number of squares needed to complete your roofing project. You can use the following formula or click here to use a simple online calculator.
Formula for calculating the roof surface area:
Once you have your roof’s pitch, divide the number by 12. (For example, if your roof’s pitch is 4 in 12, you would divide 4 by 12. This would yield 1/3.)
Next, square your result. (If your number is 1/3, squared would yield 1/9.)
After that, add 1 to your number. (1/9 + 1 = 10/9.)
Next, figure out the square root of your new number. (The square root of 10/9 is 1.05.)
Next, use your measuring tape to measure the length of your house. (Be sure to include overhangs.)
After that, measure the width of your house. (Be sure to include overhangs.)
Multiply your house length by your house width to get the area. (For example, 40 feet x 30 feet = 1,200 square feet.)
Next, multiply the area by your roof’s pitch. (1,200 x 1.05 = 1,260 square feet.)
To allow for hips, ridges, and waste, add 10% of your final number for a gable roof and 17% of your final number for a cottage roof. (Your total number would be either 1,386 or 1,474 square feet.)
What roofing material should I use?
The right roofing material for your home really depends on just a few factors: Budget, area of the country you live and personal preference. Most people think of the budget first, however the area of the country where you live should be the priority. For example, if you live in an area that is prone to hail or high winds you may be out of pocket for more repairs or another roof replacement if you don’t choose the right materials. See the wind speed map below for reference.
In areas with high wind speed putting on a shingle not rated to withstand those winds can cost you a lot of money in repairs over the life of your roofing system. For those in hail prone areas you may consider an impact resistant shingle. Choosing the right roofing material can save you a lot of money in the long run.
Well how do I know if the materials will meet the specifications required for the area I live? Good news is that all major manufacturers of shingle, metal, flat roof, and synthetic roofing systems test and list their product specifications online and on the package. The better news is finding this information is easy. For instance, if you want to install a GAF shingle roof you can go directly to their website, select the shingle you are interested in then click on specs. The specs list their hail classification as well as the wind warranty associated with the shingle.
Now, metal specifications are a little trickier, the wind rating on metal panels is really around the method used to install the panels to your roof. We won’t get into all of the details on metal roofing in this article, but we certainly do not recommend DIY roofing for metal products.
Synthetic roofing materials like F-Wave have come a long way in the last ten years and offer the best of both worlds when it comes to hail and wind protection. The ratings on synthetic shingles are posted on their site as well, but it is much more interesting to dig through the videos of their testing as they often far exceed their stated rating for wind and hail when real world testing is conducted.
Once you determine the material that best meets or exceeds the minimum specifications for your home, you can move to the fun step of picking your design. The number of styles available at any price range for roofing materials is immense. Larger shingle manufacturers like GAF have style guides that allow you to upload a photo of your home and model different roofing systems to help select the look you are going for. Metal manufactures are usually smaller and more local to your area due to the cost of shipping the materials. Since they are smaller these manufacturers typically do not invest as heavily in design tools so you will have to visualize what the style and profile of the panel will look like on your home. Whatever the material, your preferred contractor usually has samples in stock and can consult with you on the best look for your home.
Other Factors that Affect Price
There are several other components that are required for your roofing system other than the shingles or metal you choose. These include the type of underlayment, flashings and ventilation. While these items may be trivial, they are the areas that are most likely to fail in your roofing system.
Pipe boots are an area to pay special attention to. There are multiple different types of pipe boots on the market with varying degrees of life expectancy. One of the most common materials used for pipe boots is a neoprene pipe boot that has a rubber ring that seals to the vent pipe on your roof. The problem with this type of pipe boot is that rubber expands and contracts with the change of temperature causing the pipe boot to fail in 7-10 years in areas that are more prone to temperature swings. With your typical roofing system expected to last 25-50 years you now have a component that is going to fail and cost you money down the road. There are slightly more expensive alternatives including lead and lifetime pipe boots. Lifetime Pipe Boots, from Lifetime Building Products also come with an extended warranty guaranteeing them from failure. They are able to do this because they use silicone instead of rubber. Spending a little more money on these components when you first replace your roof can save your hundreds of dollars down the road.
Underlayment, the vapor barrier that goes between the decking and your roofing membrane, is another component that has multiple options to choose from. The industry has come a long way from the tar paper (felt) that’s been used for centuries. A lot of contractors, especially new home builders, still use economy felt underlayment as a cost saving measure, however this cost saving measure can end up costing the homeowner a lot of money in repairs. If you are not going to upgrade your underlayment, you should consider putting ice and water underlayment on the most vulnerable areas on your roof (valleys, roof openings, roof/house intersections and the eaves).
Your roofing contractor should provide you with a list of all of the components that are going to go on your roof. Pay special attention to the brands they list as many extended warranties require you use the manufacturers roofing components throughout the system to qualify for coverage. If your contractor refuses to give this information to you, you should look elsewhere as they are likely taking short cuts.
Steep and Second Story Charges are additional costs the contractor incurs due to the higher price of labor associated with installing your roofing system on steeper pitched roofs. Steeper pitches take more time to install and require added safety standards to keep the crews safe. The added labor costs are then passed to the homeowner, this can add $10-$30/per square depending on the height or pitch of your roof.
There are some other items that your contractor may not discover until they remove the existing roofing materials from your home. While your contractor should identify things such as damaged or rotted fascia prior to installation they may not be able to identify rotted or damaged decking prior to removing the existing roof.
Your contractor should discuss these potential concealed conditions with you and it should be clear in the agreement that you sign what the cost for those items will be. For example, you should see a line item in the contract stating what the price per square foot will be to replace damaged decking on your roof. If these items are not clearly stated you should consider another contractor.
These concealed conditions are also why you should ensure your contractor plans to remove the existing roof all the way down to the decking. While becoming less common, there are still roofing contractors that will try to take a shortcut and leave the existing felt in place and run new felt over the existing felt. While in theory you could argue this gives another layer of protection you are also unable to ensure the decking is undamaged to ensure a nailable surface as required for all manufacturer warranties. DO NOT TAKE THIS SHORT CUT! You will end up paying more in the long run.
Whew that was involved! Do roofing contractors go through this entire process every time they quote a roof? The answer is no, technology has come a long way in the last several years, for example, there are now software programs that use satellite imagery to determine measurements in seconds. While the roofing contractors of yesteryear had to hand measure every roof, today's roofers can have you a quote in minutes.
Your roof is the first line of defense from your home. The most important consideration when it comes to installing a new roofing system on your home is selecting the right contractor. Take your time and make sure you are considering like for like when comparing quotes. Ultimately the process will go much smoother if you are working with a contractor who has earned your trust.
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