Testing and Analysis Methods

ROOFTECH offers a wide variety of non-destructive roof testing services. ROOFTECH personnel are trained and certified in the administration of these tests, which provide precise information about the condition of a roofing assembly that can guide corrective action and reduce the expense of repair:

Built-up Roof Test Cuts (ASTM D2829, D3617)
A square foot of roof is cut, weighed, measured, and broken down into its component parts. The analyst uses a computer program to determine whether the correct number of plies and amount of interply mopping has been used in the roof's construction.

Core Sample Analysis
Two inch diameter cores are taken from an existing roof and broken into its plies with a careful administration of heat to determine how the roof was constructed.

Fastener Pull Test
The analyst measures how many psi of force are required to pull a fastener from a specified deck, determining both the strength of the roof assembly and the fastener that will hold the roof to the deck.

Gradation of Gravel (ASTM D1863)
A sample of the gravel is weighed and then passed through sieves that divide it into various sizes, which are then weighed separately. The analyst thereby determines whether the gravel has the right percentage of each size to meet specifications.

Impedance Testing
Because water conducts electricity, the passage of electric current from one point to another may indicate moisture. A roof is grided into 4 foot² sections. One reading in each grid is taken with a Tramex leak seeker until the entire roof is scanned. A Delmhorst meter is a probe that can validate high conductivity in a particular spot, indicating moisture.

Infrared Thermography
Our analysts commonly use this as a first test for abnormal conditions on a roof. An infrared camera reveals warm areas. Because water holds heat, this may indicate moisture. The images identify specific areas calling for further testing to validate conclusions.

Microanalysis
A sample of roof is chemically desaturated into individual plies. The analyst then uses a magnifying camera to check for damage to fibers in each ply. We use this frequently to determine the extent and depth of hail damage.

Moisture Content—Oven-Drying Method
A sample from the roof is double-bagged in plastic, weighed, then slowly dried in an oven for a minimum of 24 hours at 200 degrees or less. The analyst weighs again and repeats the process until the weight stabilizes. The difference in weight at the beginning and end of the process reveals the moisture content of the roof at the beginning of the test.

Negative Uplift (FM 1-52)
To determine whether a roof can withstand strong winds, the analyst uses an acrylic dome to produce a 5'x5' vacuum on the roof.

Water Testing
In order to locate a point of water infiltration, a portion of roof or wall is subjected to water for a period of time. For low slope roofs, drainage is blocked and water is allowed to stand. For walls, spray is used. In both cases, the analyst begins the water low and gradually raises it until the problem area is located.