WRITTEN BY Jordan Craig ON August 20, 2019
Having a roof over your head is a common phrase that means having a place where you can stay and find shelter. Most people are satisfied with this definition and leave the technical details to others such as architects, engineers, contractors, and insurance companies. To these professionals, the type of roof system on commercial and residential buildings, offers a varied range of functional characteristics that must be considered for costs, design, function, aesthetics, and long-term performance.
The most common roofing types (from most economical to most costly) are asphalt shingles, synthetic shingles, single- and multi-ply roof systems, architectural metal panels, and slate roofing. All these roofing types are used on commercial buildings, although asphalt shingles and synthetic shingles are commonly used on residential buildings. Single- and multi-ply roof systems are best suited for low-slope roofs, while the other types work well on steep-slope roofs. Slate is an expensive choice for roofing materials, and one of the least commonly used on new construction and during roof replacements. The higher cost of slate is due to production from quarried materials and additional labor required for installation.
However, slate roofing can be an exceptional choice in the right circumstance. While costlier than other common roofing materials, slate offers some advantages. One of the main benefits of slate roofing is that it is robust and resistant to both hail and wind. Furthermore, an additional benefit of slate is the overall architectural aesthetic roofs with slate exhibit. It should be noted that a properly maintained slate roof can last upwards of 75 years or more. Even though slate is robust against wind and some hail, damage to slate roofs typically results from foot traffic by someone who lacks proper knowledge of the material when performing repairs or accessing the roof for other purposes. Because slate is easily damaged by inexperienced foot traffic, additional precautions should be maintained during assessments and maintenance of slate roofing.
When damage allegedly occurs and an insurance claim is made, care must always be taken not to further damage the slate by walking on it. Slate roofs are often steep and difficult to walk on anyway. In order to assess a slate roof, heavy machinery boom lifts are typically utilized in order to gain visibility without stepping on the roof itself. However, boom lift rentals can be expensive for property owners and insurance companies, ranging between $1,000 and $4,000 per day, depending on the size and location of the lift. Other considerations are where the lift will be parked onsite in order to access the roof. If the parking area around the building is limited this will limit overall access to the roof and the ability to properly perform an assessment.
New technology, such as drones, have integrated within the consulting community in order to assist with performing assessments at hard-to-reach areas. Drones can capture and record photographs and videos to document the condition of slate roofing. They can cover the entire area of the roof, including sections not reachable by lift or ladder. This technology can be effective by eliminating the concerns associated with boom lifts. The use of drones in consulting can also cut down on third-party engineer costs since no boom lift rental is required.
A slate roof is one of the most visually appealing and durable of all roofing systems. However, if improperly designed or installed, it can lead to costly repairs. Common errors can include incorrect detailing, nailing slates too tight, which can lead to cracking, and improper maintenance practices. Pie has extensive experience in design (both as a third-party reviewer and designer of record), quality assurance review during installation, annual asset management programs, and insurance claims to accurately address the cause of damage to a slate roof.
On the Colorado State Capitol roof renovation project, Pie provided third-party design review and observed the installation of slate roofing. Most recently, Pie investigated for a hail and wind insurance claim. The homeowners presumed that damage was caused by the weather-related event. However, Pie’s investigation concluded that the cause of damage originated from foot traffic. Ultimately, when designed, installed and maintained properly, a slate roof will provide literally decades of functional performance and enjoyment that will showcase the best aesthetic aspects of your building.
About the Author
Jordan Craig has experience enriched with structural design, various construction assemblies, building codes, project management, and building envelope consulting. This experience has developed him as an Engineer and has allowed him to mentor and train younger engineers who are working towards their professional licensure. Jordan defines himself as a team player and is always available to assist and to share knowledge with others around him. His engineering experience and positive attitude contributes to the culture at Pie. His favorite types of projects are diagnosing issues with building construction and working towards remedial repairs. His favorite challenge is being exposed to something new, which grows his engineering knowledge.