Grades and Specifications - Burt Forest

1 Grades ANDSPECIFICATIONSPRODUCT GUIDEAPAThe Engineered Wood AssociationCONTENTSI ntroduction ..3 Key Definitions ..4 APA Trademark ..4 Product Standard PS 1-83 ..4 APA Performance Standards ..5 grade ..5 Exposure Durability ..5 Species Group Number ..7 Span Ratings ..7 APA Performance Rated Rated Sanded and Touch-sanded plywood ..14-15 APA Specialty Grades ..16 Guide to Specifications ..17-20 Storage and ..21-22 Method of Ordering ..23 grade APA ..24 INTRODUCTIONThis guide to APA The Engineered WoodAssociation panel Grades and Specifications ismeant to serve as a useful reference source forstructural wood panel users, specifiers,dealers and distributors. It contains keyinformation about the many structural woodpanel Grades produced by APA member mills,including APA Performance Rated Panels,sanded plywood , and specialty illustrates and explains APA provides a comprehensive guide toarchitectural Specifications .

2 And it containspanel installation recommendations fortypical construction complete panel applicationrecommendations or additional productinformation, consult any of the other APApublications cited throughout this for additional specification or designassistance, contact the nearest APA regionalfield office listed on the back trademarked structural wood the very best in versatility, durability hundreds of construction,industrial and do-it-yourself applications. 1995 APA The Enginnered Wood AssociationAPA TRADEMARKThe APA The Engineered WoodAssociation strademarks appear only onproducts manufactured by APA membermills. The marks signify that themanufacturer is committed to APA srigorous program of quality inspectionand testing and that panel quality issubject to verification through APA audit a procedure designed to assuremanufacture in conformance with APAperformance standards and/or Standard PS 1-83 for Constructionand Industrial and touch-sanded panels,and panels with B or better veneer onone side only, usually carry the APA trade-mark on the panel back.

3 Panels with bothsides of B or better veneer, or withspecial overlaid surfaces (such asMedium Density Overlay), carrythe APA trademark onthe panel PRODUCTSTANDARD PS Product Standard PS 1-83 forConstruction and Industrial plywood is avoluntary commodity standard developedcooperatively by the Department ofCommerce and the construction andindustrial plywood industry. PS 1-83establishes requirements for producing,marketing and specifying construction andindustrial plywood . With the exception ofPlyron and some APA Performance RatedPanels, all of the other plywoodgrades described in this guideare produced under theprovisions of ProductStandard PS 1-83. Panels conforming to the productstandard carry the notation PS 1-83 inthe lower portion of the APA a complete copy of ProductStandard PS 1-83 for Construction andIndustrial plywood , Form H850, write theAPA The Engineered Wood DEFINITIONST ongue-and-groove4 APA PERFORMANCESTANDARDSAPA performance standards are the resultof manufacturing technology that makespossible the manufacture of structuralpanel products from wood by-productsand species not provided for in Standard PS 1-83.

4 APA perfor-mance standards deal exclusively withhow a product must perform in a desig-nated application rather than from what orhow the product must be produced under APA performancestandards called APA Performance RatedPanels must meet several performancebaseline requirements according to thepanel s designated end use. These perfor-mance requirements include uniform andconcentrated static and impact loadcapacity, fastener-holding ability, rackingresistance, dimensional stability, andbond addition to conventional veneerplywood, APA performance standardsencompass such other panel products ascomposites and oriented strand board.(See APA Performance Rated Panels,page 8.)For complete performance testing andqualification information, write APA forPRP-108, Performance Standards andPolicies for Structural-Use Panels,Form term grade may refer to panel gradeor to veneer grade .

5 Panel Grades are gen-erally identified in terms of the veneergrade used on the face and back of thepanel ( , A-B, B-C, etc.), or by a namesuggesting the panel s intended enduse ( , APA Rated Sheathing,Underlayment, etc.).Veneer Grades define veneer appearancein terms of natural unrepaired growthcharacteristics and allowable number andsize of repairs that may be made duringmanufacture. The highest quality veneer is A, (1)the lowest D. The minimum gradeof veneer permitted in Exterior plywood is C. D veneer is used only in panelsintended for interior use or forapplications protected from permanentexposure to the DURABILITYAPA trademarked panels may beproduced in four exposure durabilityclassifications Exterior, Exposure 1,Exposure 2, and Interior. The exposuredurability classification relates to gluebond, and thus to structural aesthetic (non-structural) attributesof panels may be compromised to somedegree by exposure to weather(2),installation recommendations in thispublication are designed to provideoptimum overall panels have a fullywaterproof bond and are designed forapplications subject to permanentexposure to the weather or to moisture.

6 Exposure 1 panels have a fullywater-proof bond and are designed forapplications where long constructiondelays may be expected prior to providingprotection, or where high moistureconditions may be encountered in 1 panels are made with the sameexterior adhesives used in Exterior , because other compositionalfactors may affect bond performance, onlyExterior panels should be used forpermanent exposure to the weather.(3)TYPICAL APATRADEMARKSRATED STURD-I-FLOOR000PS 1-83 UNDERLAYMENTPRP-108 APA24 oc23/32 INCHSIZED FOR SPACINGT&G NET WIDTH 47-1/2 EXPOSURE 1 RATED SHEATHING32/16000 PRP-108 HUD-UM-40 CAPA15/32 INCHSIZED FOR SPACINGEXPOSURE 1000PS 1-83 FHA-UM-64 PRP-108 APASIZED FOR SPACINGEXTERIORRATED SIDING303-18-S/W11/32 INCHGROUP 124 ocPanelgradeSpanRatingThicknessMillnumbe rExposuredurabilityclassificationProduct StandardPanelgradeSpanRatingThicknessMil lnumberExposuredurabilityclassificationP anelgradeSpanRatingThicknessMillnumberEx posuredurabilityclassificationAPA s Performance-RatedPanel StandardSidingface gradeSpeciesgroupnumberHUD/FHArecognitio nProduct StandardA-B G-1 EXPOSURE 1-APA 000 PS1-83

7 FaceveneerExposuredurabilityclassificati onBackveneerSpeciesgroupnumberMillnumber ProductStandardRATED SHEATHING48/24000PS 1-83 C-CPRP-108 APA23/32 INCHSIZED FOR SPACINGEXTERIOR000PS 1-83 APAEXTERIORA-CGROUP 1 RATED SHEATHING32/16000 PRP-108 HUD-UM-40 CAPA15/32 INCHSIZED FOR SPACINGEXPOSURE 1A-D000PS 1- 83 APAGROUP 1 EXPOSURE 15 NOTE: All-veneer APA Rated SheathingExposure 1, commonly called CDX in thetrade, is frequently mistaken as an Exteriorpanel and erroneously used in applicationsfor which it does not possess the requiredresistance to weather. CDX should only beused for applications as outlined underExposure 1 above. For sheathing gradepanels that will be exposed permanently tothe weather, specify APA Rated SheathingExterior (C-C Exterior under PS 1.)See Treated plywood (page 18) forrecommended plywood Grades and exposure durability classifications in applicationsrequiring fire-retardant-treated orpreservative-treated plywood .

8 (1) Some manufacturers also produce a premium N grade (natural finish) veneer, available only onspecial order.(2) Although glue bond durability is described byexposure durability classification, panel surface maybecome uneven and irregular under prolongedmoisture exposure. Panels should be allowed todry, and panel joints and surfaces may need to besanded before applying some finish materials.(3) Exposure 1 panels may also be used whenexposure to the outdoors is on the underside only,such as at roof 2 panels (identified asInterior type with intermediate glueunder PS 1) are intended for protectedconstruction applications where onlymoderate delays in providing protectionfrom moisture may be , paintable. Not more than 18 neatly made repairs,boat, sled, or router type, and parallel to grain, or synthetic repairs permitted.

9 May be used for naturalfinish in less demanding surface. Shims, sled or router repairs, and tight knots to1 inch across grain permitted. Wood or synthetic repairspermitted. Some minor splits C veneer with splits limited to 1/8 inch width andknotholes or other open defects limited to 1/4 x 1/2 some broken grain. Wood or synthetic knots to 1-1/2 inch. Knotholes to 1 inch across grain andsome to 1-1/2 inch if total width of knots and knotholes iswithin specified limits. Synthetic or wood repairs. Discolorationand sanding defects that do not impair strength splits allowed. Stitching and knotholes to 2-1/2 inch width across grain and1/2 inch larger within specified limits. Limited splits permitted. Limited to Interior, Exposure 1 andExposure 2 GRADESRATED SHEATHING40/20000PS 1-83 C-CPRP-108 APA19/32 INCHSIZED FOR SPACINGEXPOSURE 2 RATED STURD-I-FLOOR000 PRP-108 HUD-UM-40 CAPA20 oc19/32 INCHSIZED FOR SPACINGT&G NET WIDTH 47-1/2 EXPOSURE 2 Interior panels which lack furtherglueline information in their trademarksare manufactured with interior glue andare intended for interior applications GROUP NUMBERP lywood manufactured under Standard PS 1-83 may be madefrom over 70 species of wood.

10 Thesespecies are divided according to strengthand stiffness properties into five 1 species are the strongest andstiffest, Group 2 the next strongest andstiffest, and so on. The Group numberappearing in an APA trademark is basedon the species used for face and backveneers.(1)Some species are used widelyin plywood manufacture; others local availability if a particularspecies is RATINGSSome APA trademarked panels APAR ated Sheathing, APA Rated Sturd-I-Floorand APA Rated Siding carry numbers intheir trademarks called Span denote the maximum recom-mended center-to-center spacing ininches of supports over which the panelshould be placed in Rated Sheathing Span Ratings appear as two numbersseparated by a slash, such as 32/16,48/24, etc.(2)The left-hand numberdenotes the maximum recommendedspacing of supports when the panel isused for roof sheathing with the longdimension or strength axis of the panelacross three or more supports.