The size of a roof is one of the biggest factors that determines how much the replacement will cost. Unfortunately, this size cannot be assessed from the square footage of the house alone. Roofers calculate the size of a roof in squares. These squares measure 10 by 10 feet and the number of squares counted is used to determine the size of the roof.

Besides the shingles which are used to roof a building, there are a lot of other different materials which go into the roof replacement process. The cost of materials like nails, underlayment, ice and water barrier, and roof flashing are included in the cost of roof replacement. The material used for the roofing is also one of the biggest factors that determine the cost of the project. A shingle roof is the most popular type of roof used, with about 60% of houses using shingle roofs. Metal roofs however can cost up to two times the cost of an average shingle roof. Clay and concrete tiles are another material which can be used in roofing. These generally cost the same as metal roofing but it has to be determined if the house is structurally capable of holding up the extra weight of these tiles. Most houses with concrete or clay tiles are designed to carry this weight from the get go. Rubber roofs and bitumen roofs although rare can also be considered.

The pitch of a roof refers to it’s slope. The higher the slope of the roof, the more materials are needed to complete the roof, it can also determine the type of material that has to be used. The pitch is determined by the number of inches the roof rises vertically for each horizontal foot. Roofs have four classifications based on their pitch. A flat roof has a pitch less than 2:12. A water proof material such as modified bitumen or rubber is advised for a flat roof. It is generally cheaper to install a flat roof because it uses less materials and is easier to install than others. A roof with a pitch of between 2:12 and 4:12 is a low-pitched roof. A conventional roof has a pitch ranging from 4:12 to 9:12 while a high-pitched roof can be as steep as 21:12. High-pitched roofs are the most expensive to install due to how difficult it is to install them. There’s also the additional cost of safety measures that have to be applied to high-pitched roofs.

The height of the roof from the ground influences the cost of installing the roof. You will have to pay more to install a higher roof. Due to the greater danger associated with working on a roof that’s higher off the ground, labour costs tend to scale with increase in roof height.

Roof installation can be dangerous and difficult. Due to this, skilled workers willing to do roof installation are quite few. This shortage in workers has led to an increase in labour and installation prices of roofs. A roofing project is however a very delicate one which shouldn’t just be handed over to the company with the lowest asking price. It is important to do your homework about the company you will be contracting your roof replacement out to. Check out reviews of companies on the internet before you settle for one.

6. Unforseen costs

Some damage to a roof is never realized until the old roof is removed. The underlying sheathing for the shingles which is often made out of plywood may have been damaged during the removal of the old roof. It may also have been damaged due to a leak in the shingle which exposed it to moisture. This can drive up the cost of your roof replacement, especially with the increasing cost of timber due to forest fires and the COVID-19 pandemic. Other unforseen costs may creep up due to the complexity of a roof design or the addition of skylights. Roofers generally tend to charge more for the installation of skylights due to how difficult it is to work around them. The layers of the old roof need to be removed before work begins on installing a new roof. A roof with a lot of layers that have to be removed due to water damage or rot will jack up the price of the installation as the overall labour cost will increase.