When looking to have a commercial roof replaced having a commercial roof investigation done will allow you to know what options you have in re-roofing. A thorough roofing contractor will take the proper steps to make sure they know what the existing roof system is before a bid is created. Why is this so important you ask, simply put you cannot guess when it comes to roofing.
The first part of a commercial roof investigation is to do a core cut. A core cut is a snapshot of what the existing roof system is by means of destructive testing. This is done to expose all layers of roofing and to determine what type of roofing deck is present if not accessible from inside the building.
3 layers of roofing present with the base layer being over 50 years old
Once the core cut has been completed the next step is to verify the roof penetrations will meet the flashing height requirements of the manufacturer. Typically roof manufacturers require a minimum of 8″ of flashing height to be considered a “warrantable” detail. This height allows enough room from where the roof starts to a place where if water/snow saturated the area it would not overflow in to the building. If the roof penetrations do not allow for the proper flashing height to be achieved the penetration may be extended or raised to satisfy the condition. The most common case of this is raising a HVAC curb or a gas line penetration.
When looking at commercial roofing options you can tear off the roof completely or “recover” the existing. If the roofing deck is not going to be exposed with a tear off a roof manufacturer will typically require two additional tests to warrant a recovered roof. The first is a moisture survey which can be completed using a handful of different methods. The most two common varieties are electrical impedance metering and using an infrared camera.
A Tramex Dec scanner detects and evaluates the moisture conditions within roofing systems by non-destructively measuring the electrical impedance. A low frequency electronic signal is generated, transmitted into the material under test via one of the two electrodes incorporated in the rubber electrode mat, and received by the second electrode. The strength of this signal varies in proportion to the amount of moisture in the material under test. The Dec Scanner determines the strength of the current and converts this to a comparative moisture content value. By moving the Dec Scanner across a roof surface in a regular pattern, a continuous reading is obtained, and areas that contain moisture can be readily identified.
Tramex Dec Scanner
Moisture detected in the roofing system
Infrared roof inspections can detect the source of a leak. Moisture seeps into a roof system long before it ever shows indications within the building’s conditioned or working spaces and breaks through to drip down walls, stain ceilings or create pools on the floor below. The water trapped in the roofing system will retain heat after the sun has gone down and will show up as variation in temperature with an infrared camera.
Blue areas shown above are dry, yellow and red are holding moisture
Once a roof has been inspected and tested to make sure it is dry the next step is to verify the integrity of the roofing deck or if adhering a new roof to the old to test the adhesion strength of the existing roof. To verify the integrity of the roof deck a pull test is performed using a fastener and device used to measure the failure point of a fastener. The test measures the amount of uplift required in pounds for the fastener to physically pull out from the decking. This test is performed a minimum of 6 times on a roof in various locations. The requirements of the test can change based on the size of the roof.
Example of an deck adhesion test
In situations where a new insulation layer will be adhered to an existing roof an adhesion test is performed. The surface of the roof is prepped and a layer of insulation is installed in adhesive and allowed to set. Once set the test can be performed, a successful test is when the insulation layer fails before the adhesive does.
Documentation of testing results is critical in maintaining the roofing manufacturer’s warranty and to protect an owner down the line. Investigating on the front end help to keep projects on time and on budget. Call Delta Innovative Services today to discuss your roofing project 913-371-7100
If you are interested in extending the life of your roof go to https://www.deltaservices.com/commercial-roof-repair/ to request repair and roof maintenance services from us.
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