Thermaco Engineering Services — Roof Consultants Infrared Inspection Services Roof Construction

Thermaco Engineering Services - Roof Consultants Infrared Inspection Services Roof Construction

Frequently Asked Questions

Flat Roofing

Q: How often should I be inspecting my roof and how much should this cost?

A: At least twice a year have a professional either roof consultant or roofing contractor inspect your roof both in the spring and fall. The inspector should ensure that all roof drains are working and free of debris. Your roofer or consultant can prepare a bi-annual inspection check list suited to your application. Costs will vary from location and size of building, but generally this should be in the price range of $ 500.00 — $ 1,000.00.

Q: How often should an IR scan be carried out and how much should it cost?

A: An infrared roof scan should be carried out at least once every three to four years depending on age of the building. Buildings less than 15 years can be scanned every three to four years. Older buildings should be scanned every 2nd year or if leaks are occurring more frequently. An infrared scan for buildings smaller than 40,000 sq. ft. should cost less than $ 1,200.00. Buildings greater than 40,000 sq. ft. will be charged out on a per sq. ft. basis in the range of 1.6 cents — 2.5 cents per sq. ft. depending on complexity and consultant selected. Buildings larger than 750,000 sq. ft. will cost in the range of 1.2 cents — 2.0 cents per sq. ft.

Q: How should I decide whether to continue to repair my roof or replace it?

A: We generally use a rule of thumb. If you have wet anomalies or wet areas in the roof system scattered over the complete roof section and the value of the wet insulation is greater than 25% of the total roof area then your choice should be to replace this roof. If you only have one wet area in a concentrated area greater than 30% of the total roof area replace the roof. Above all the age of the roof and general conditions of the roof flashing and membrane system should be considered in the replacement decision.

Q: How does a roof consultant decide on the type of construction to be used on my roof?

A: There are many factors involved in the decision process for the type of roof construction.Some of these factors include but are not limited to the following: cost constraints, life expectancy, warranties, environment, building height, roof access, roof traffic, drainage, existing roof construction and reuse of good materials, construction constraints, access for construction, type of deck, R value of insulation, building codes, qualification of trades in area, aesthetics, etc.

Q: I understand that phenolic insulation can corrode my deck. If this is true, how do I know if I have a problem? Do I have to replace this roof now?

A: Phenolic insulation is no longer used in the roofing industry as a insulating product. Phenolic insulation if wet will generally turn to acid and attacked galvanized and non galvanized steel decks. However, this product is not a problem over concrete or wood decks. Phenolic insulation is also not a problem over gypsum boards sealed with a vapour retarder. If you are unsure whether you have phenolic insulation, contact us, a roofing contractor or another consultant and ask for core cut verification. We suggest that phenolic insulated roofs be scanned at least once every two years. If the roof is dry then there is no need to replace your roof at this time. Some of the previous manufacturers of phenolic insulation provide technical assistance and financial assistance to replace damaged insulation, decking or systems. Some of the previous manufacturers to visit their sites include Koppers and Domtar.

Q: All of the contractors I talk with speak about Factory Mutual wind requirements. What does this mean and how do I contact them if I am not sure?

Thermaco Engineering Services - Roof Consultants Infrared Inspection Services Roof Construction

A: Factory Mutual is an insurance body who assist our industry to provide guidelines to reduce losses caused by fire and wind in the roofing industry. There are three sets of data base on wind pressure which establish how a building roof sub assembly should be secured to the deck, i. e. FM — I — 60, FM — I — 90 and FM I — 120. These three design factors are controlled by wind velocities in the area your building is situated in. Building heights and shape are considered factors in the evaluation. Basically Factory Mutual assists the consultant and contractor in determining the method of mechanically fastening your insulation system down. For more information go to our link with Factory Mutual.

Q: What R value do I need on my roof?

A: We now have new energy codes coming out which will soon become part of the Ontario Building Code. R value will vary for type of occupancy and geographical location. For an example a residential apartment in Toronto area requires R 20. That same apartment building in Timmins may require R24 or higher. An industrial building in Toronto may require R 12 minimum but in Virginia this value may be lower. Several states also have their own building codes. You should always inquire with your local government building department to determine what codes govern your area.

Q: When do I need a vapour retarder?

A: A vapour retarder should be used where there is the possibility for moisture to rise above the deck system. i.e. residential buildings, food processing, restaurants, hospitals, schools,pulp and paper process or any area of high humidity.

Q: How much should a roof replacement cost?

A: Costs will depend on several factors. Height of your building, access for garbage removal and set up, complexity of the design, warranties, familiarity of the contractor with the materials selected by the consultant, time of year, environmental conditions, existing roof material conditions, etc. We have listed some of the general price guidelines for retrofit to roofs in Ontario.


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