The amount and type of reinforcement in a roof system will provide much information about the performance and service life of a roof system.
The number of plies or layers in a roof system will provide much information about the performance and service life of a roof system.
The quality, type and amount of waterproofing compound or adhesive in a roof system will provide much information about the performance and service life of a roof system.
The quality of the roof system materials is also a major consideration for a roof system – not all materials are equal and performance of those materials will vary.
Other major considerations for a roof system are the quality of the labour that installs the roof system – low quality labour will produce a poor quality, problem-plagued roof system.
A quality roof system requires excellent design, high quality materials and high quality labour – if any of those three requirements are not fulfilled – the roof system will not perform to a suitable standard.
The roof system must be designed to suit the building and the materials incorporated in the roof system design must be well considered for that building.
If a poor quality roof system is installed on a building – then that system will fail prematurely and will require replacement. The more difficult the location and access, the more sensitive the use of the building – the more costly the replacement will be. A large empty roof area on a warehouse in an open site with good access all around will produce a relatively low cost roof replacement scenario.
A building in a congested, urban area on a size constrained site, with poor access, poor space for roofing personnel on the roof areas and a sensitive occupancy will produce significantly higher roof replacement costs. It is always so important to install the best, highest performing, longest service life roof systems on these most complicated and expensive locations/situations.
I present some comparative examples – for these examples, I will assume that the new roof system to be installed is the same for both projects (2020 dollars):
Project 1 – a quality manufacturing plant – Owner occupied, long term hold – approximately 100,000 square feet – roof replacement cost approximately $30.00 psf.
Project 2 – a Hospital obviously long term hold, very poor access, very congested roof areas, very sensitive occupancy, urban location, all activities constrained – $150.00 psf
Project 3 – high rise apartment building, current access is good, new construction, long term hold, quality building – $35-40.00 psf – NOTE: roof replacement on this site – if a poor quality roof system is installed – the project cost will balloon to $85-95.00 psf (in today’s dollars) – with extreme amounts of management input
Project 4 – 2-3 story historic urban building, poor access, congested roof areas, long term hold, roof replacement access and details impossible – $80-90.00 psf – roof replacement in the future will be essentially impossible – if attempted – replacement costs will range into $250.00 to $300.00 psf
NOTE: To emphasize – the same roof system is envisioned for all four projects – the physical location of the building, the access to the roof areas, the ability to move on the roof areas, the number of units and projections, the perimeter details and all other considerations are very important and affect the cost of roof system installation dramatically.
These are real numbers.
The Hospital building is a project is currently ongoing. It is difficult, expensive and slow moving.
The interesting element (for this discussion) of the Hospital situation is that the roof systems on the roof areas that are being replaced are only about 15 years old. Poor design, poor system selection and poor labour resulted in failure of the roof systems. Now the Hospital is paying the huge price to replace these inferior, poorly installed roof systems. If the existing roof systems had been properly designed and installed – those systems would be performing for the next 25 years or more. It is a waste of money, management time, patient inconvenience, resources and inconvenience to be replacing the roof systems after only 15 years – the insulation in several sections of the roof systems was saturated.
The new roof system will be in place on the Hospital for the next 40 years plus – the new roof system is being installed the right way – good design, good materials, good labour, excellent attention to detail – this is only way to install a roof system on a difficult roofing situation. The NOW COST is a minimal consideration when considering roof systems for these types of buildings. The cost to replace roof system dwarfs the initial installation.
