b'~ All the materials were mounted in August and were left in pla until Decemce ber. T experienced temperatures from highs of 100 F. to lows of 25 F. hey They experienced rain storms of up to 2 inches,snow and several days some of frost. Observations at the end of the weathering proc~ss included increased wrinklingofsomesamples, andsomechangesin dimensionalstabilitythat resulted in pulling of the sheet against the nails.observation was a little This troubling because it occurred in just eight feet. O would expect it to be more ne pronounced in longer runs. One of the hybrid samples completely failed, but upon close inspection we discoveredsample was mounted wrong side up. It will be re-tested. We that noted that the surface of the rest of the samples exhibited little degradation. esearch The samples were then taken down and sent to Structural R for testing.cept forsample that failed,samples were subjected to two ASTM Ex theall Synthetic Underlayments:tests.first was ASTM D4869-05 - Standard Specification for Asphalt-SatuThe Testing and Observationrated Organic Felt Underlayment Used in Steep Slope Roofing, Section 8.3, Liquid Water T ission T also known as the water spray test. ransm est, By Kurt Baumgartner, T&R Committee Adviser D the 2006 spring MRCA board uring of directors meeting, the Technical and Research Committee decided to undertake the testing and observation of synthetic roof underlayments. Thereasonsforthisdecisionwere threefold.First,theproliferation of these types of products in the last few years; second, the claim that these products are durable enoughto serve as temporary roof coveringsin excess of 1 days; and finally, claims of various attributes based on stan The second test was ASTM D1970-80 dards thatproducts have not been tested against.01- Standard Specification for Selfthese Our basic procedure was to gather samples of the various materials fromAdheringPolymerModified distributors\' warehouses. We received eight different materials. Six were trueB SheetMaterialsUsed as ituminous synthetics and two were asphalt-synthetic hybrids. The products ranged inSteepR UnderlaymentforIce oofing size from 36 inches to 60 inches.Dam Protection, Section 7.9-Self Seal We then took the samples to ation in Wichita, Kans. where they wouldability(HeadofWaterTest}5 Inch locabe mounted on test panels for extended weathering. The panels consisted ofHead of Water. As you will notice neifour-by-eight inch sheets of 7/16" plywood mounted on 2x4" framing at 4 therofthesetestsarespecifically /12 slope, four feet off the ground at the low end,facing due west.applicable tothesyntheticmaterials all terialsthethere The ma were all attached topanels with plastic cap nails, per eachtested. The reason for this is that manufacturer\'s fastening pattern. If the materialwider than four feet, thearenocurrenttests thatuniquely was material was wrapped over the edge of the panel.address the synthetic materials. These We made some observations during mounting. We encountered snaggingtests were chosen because they most of the scrim of some products on plywood splinters, which produced tears inclosely measure the claims made by the manufacturers of some ofmatethese the material.rials. miss-hitwaf st15 Also, we noted that awith afle-head shingling hatchet wouldIn the fir test the material is mounted on ainch by 30 inch piece of 3/8 erial.apped.panel perforate the mat Appropriate caution should be taken when applyinginch plywood with all lour edges wr Theis then conditioned for these materials.24 hours at 70 to 80 F. and 30 to 55%humidity. The test panel is then relative The materials for the most part lay smooth, but some experienced minorheld at an angle oldegrees and a s er head positioned 18 inchesabovk 14howwrinkling. The wider sheets also caught more wind, but all exhibited ease ofthe sample. The sample is then subjected to aof 40 to 42 gallons of wale.J spray application.per hour for aof four hours. The sample is then removed, wiped of period 8'