b'Q.WHATIS THEMANUFACTURING DIFFERENCEBETWEENPLY WOOD, PARTICLEBOARD,ORIENTED STRANDBOARD AND WAFERBORAD? A. All veneer plywood panels consist ofodd number of an cross-laminated layers, with each layer consisting of one of more plies. Particleboard consists ofof panels comprised small particles of wood usually arranged in layers by particle size but not usually oriented. Oriented strand #board is comprised of panels of com- By Bob LaCosse. CAE pressed strand-like particles arranged in layers (usually three to five) oriented at right angles to another. panelscompressed wafer-like partiWaferboard is comprised ofof cles or flakes randomly or directionally oriented. Q.WHAT IS THEDIFFERENCEBETWEENDAMPPROOFINGANDWATER PROOFING? A. Damp-proofing is the treatment of a surface or structure to resist the passage of water in the absence of hydrostatic pressure. Whereas, waterproofing is the treatment oforto prevent the passage ofunder hydrostatic pressure. a surfacestructurewater Q.WHAT DOESTHETERM "ENVELOPE" MEANINA BUILTUPROOFASSEMBLY? A. An envelope is a continuous membrane edge steel formed at the perimeter and at penetrations by folding the base sheet or ply over the plies above and securing it to the top of the membrane. The envelope prevents the bitumen seepage from the edge of the membrane. Q.WHAT IS SKATER\'SCRACKS? A. It is curvilinear cracks in a roofing membrane that appear to relate neither to the direction ofsubstrate componentsV the application of the membrane components nor the RoofWatclt Updatedfor96! The MRCA RoofThe rest of the program remains the same. Watch program has undergone a major change for 1996. The RoofContractors are allotted a geographic area to Watch program will still be an excellent direct-mail mar avoid overlap. and participants in the program keting source for members, but it will do so withcan take advantage of custom ad design, maila brand new look!ing services, special printing opportunities and To keep the program fresh and effective.more. The Roof Watch program is one of the MRCA has redesigned the newsletters to bemost cost efficient and effective ways to martwo-colors. The newsletterfeatures aket your business. Contact the MRCA office now cover, similar to the look of MR. The articles arefor more information about this exciting prostill written by MRCA staff for current orgram. orreceive a copy ofok poten tothe new lotial clients of roofing contractors, and areRoof Watch. straightforward and easy to understand. The entire back page is still used for contractors ads, and the contractors address and phone number are prominently displayed on the cover. In the near future, contractors will be able to display their ads in two-colors as well! MRJanuary96'