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Here are three membrane fracture examples on a fully adhered PVC membrane system less than 5-years old by a manufacturer who admitted having quality control problems over a 5-year period during the mid to late 1990's.
Photos # 1 & # 2 show the top and bottom view of a typical “crescent" fracture. The crescent type fractures appear over and around the edges of seam and insulation plates and over seam welds. This crescent fracture example did not completely go through the membrane. Many of the “crescent" fractures did go completely through the polymer from top to bottom. Crescent" fractures can be mistaken for cuts. The best method to identify these defective factures is where you see the top and bottom of the membrane have the same (matching) fracture pattern, and the polyester reinforcement scrim in the middle of the membrane is intact. A cut or a puncture would have cut through both the membrane and reinforcement scrim.
Photo 1
Photo 2
Photo # 3 and # 4 is an example of the “star” type fracture. The star fracture was found in the general membrane field area and over insulation plates. The “star ” fracture example in the photo is completely through the membrane polymer ( photo # 4). Star type fracture can be mistaken for hail or other impact damage. No impact depressions were found on the insulation. The polyester scrim, in-between the top and bottom membrane layers, is still intact and was not damaged. With 100’s of fractures over a large roof area, mechanical damage was ruled out. Checking with the US Weather Center, no record of severe hail was recorded since the roof was installed, so hail damage was not a factor.
A fully adhered roof system might not leak unless the fracture is over an insulation seam. The insulation facer and adhesive under the membrane can slow or stop the leak process. Organic /inorganic mixed insulation facers were common when this roof was installed. Roof leaks can increase the risk of the insulation eventually becoming infected with mold, depending on local climate conditions and the number of roof leaks.
Photo 3
Photo 4
(Photo # 5) The small "star" fracture is shown on the upper membrane surface. Photo # 6 shows the underside of the fracture with the insulation peeled away from the bottom membrane surface. The insulation facer in contact with the membrane is turned up. The tan/brown materials on the insulation facer was in contact with the membrane under side. The tan/brown material is a combination of dirt and organic materials accumulated from the membrane fracture leaking. You can see the same materials adhered to the membrane's lower surface.
Photo 5
Photo 6
These fractures can start developing within a 4 to 8 years period after the PVC roof is installed. The PVC roof may have what appears to be a small number of fractures as shown in these photos. These membrane fractures may leak during heavy rainfall or during slow snow melts and in ponded areas. The fractures continue to increase in number from a few fractures to hundreds of fractures in a few short years as the membrane prematurely ages. The time line can vary due to climatic and local roof conditions.
The manufacturer said the basic PVC formulation during this time period performed well with no serious problems with the basic product formulation. The age/stress fracturing shown here is the result of ineffective production controls in the manufacturing process, introducing wide variations in plasticizer content and key performance compounds occuring at random times and the failure to discover the problems with post production QA testing.
This manufacturer's PVC roofs with the correct membrane formulation is performing well. Other roofs may have all defective roofing membrane and be completely covered with small fractures and stiff membrane. Some roofs may have a mixture of both good and bad PVC and you find rolls with no fractures and other rolls covered with fractures.
The PVC membrane may show signs of shrinkage with the membrane taut between fastener attachment points on mechanically fastened systems. Perimeter sheets may pull away from wall flashings and be above the roof substrate under tension. The PVC membrane may become less flexible as it ages and will feel brittle in cold temperatures. The membrane scrim is more pronounced as the membrane becomes thinner due to faster plasticizer losses as seen in Photo # 1.
On several roofs we observed, the owner started patching the fractures thinking the fractures were mechanical damage. Not until the roofs became covered with hundreds of patches over several years did the owner realize they had a material performance problem. The owner’s roof asset program with annual roof inspections was key to finding the problem. One roof was 8-years old when the fractures were discovered with only two years left on the warranty.
The membrane manufacturer has responded to these material problems and has provided either product replacement and installation or coated the roofs once the building owners or roofing contractors discovered the fractures and reported them. The membrane fracture examples shown in these photos were manufactured over a time span covering 5 or 6 years ending mid 2000. Once the production problems were discovered and identified the manufacturer changed their manufacturing process and quality control. Today we know of no problems with the manufacture’s current roofing products.
If your PVC roofs installed from 1995 to mid 2000 begin to develop fractures as shown in these photos, please contact Corporate Roof Consultants. CRC can test and identify the roofing membrane to determine what is causing the fractures and help you secure a valid warranty claim if the PVC membrane is defective. Fractures on any manufacturer’s roofing products does not mean the resulting fractures are caused by defective materials. Foot traffic, hail damage, wind blown objects and equipment servicing can also be the cause. CRC does not automatically assume the problem is due to manufacturing or formulation. It is important all leaks and fractures be reported to the roof material manufacturer within the time frame outlined in your roof warranty to keep your current warranty valid.
PVC roofing is one of the best single-ply membranes and has a long history of excellent performance. CRC has observed PVC roofs 18-years old and still in service. Compared to many roofing products, PVC is contractor friendly both in quality and ease of application.. Properly formulated and manufactured PVC and other roofing materials give years of good service. Other membranes such as TPO, especially early black TPO membranes, EPDM, Hypalon, and modified bitumen systems have seen problems with formulation, sub-components and manufacturing. The key is identifying the problem and making a warranty claim prior to warranty expiration.
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