Respondin$ to wood structural panel complaints

l|/-\OMPLAINTS are a top priority\-rthey demand quick response. The longer you sidestep a complaint, the harder it is to resolve. Customers deserve attention and respect-only a patient listener can give an intelligent response.

Your first step, after the customers have given their input, is to determine whether or not the complaint seems legitimate. If not, say so-politely but firmly. Don't waste your time with false claims. Also be sure you sold the material.

And, if in your opinion a complaint is legitimate, note all the pertinent facts before contacting your supplier: Grade

. Thickness

. Span Rating Group number Bond classification

. Mill number

. Name of trademarking agency and all other panel markings, such as production information.

Find out also the number of panels involved, the particular application and full details of what the customer thinks went wrong. Many complaints can be resolved by telephone. If this is impossible, visit the site and see for yourself. Personal appearances do wonders for customer relations. Build-ers and owners are always impressed by involvement and initiative.

Even if you finally reject the complaint, the customer will respond positively to your professionalism.

Apa Product Support

253-620-7400

Sincerity retains customers. If your supplier doesn't respond to a legitimate complaint within a reasonable time, call again and insist on action. Your APA field representative can also offer guidance and assistance.

Although APA does not participate in actual settlements, your field representative will gladly answer your technical questions and can facilitate communication in situations where APAtrademarked panels are involved.

Typical Panel Complaints

APA-trademarked panel complaints are infrequent, but if you do receive one, it is likely to be on this list:

Delamination

This is essentially ply separation due to glue bond failure. It's defined in U.S. Product Standards PS l-07 and PS 2-04. For non-PS I panels manufactured under APA Standard PRP108, see Performance Standards and Qualification P olicy for StructuralUse Panels, Form 8445, or PS 2, Form 5350.

Checking, leafing, splitting and broken grain are not delamination. Buckled panels and swelling over core gaps and knotholes are also sometimes erroneously reported as "delaminated." It's important to clarify the difference and to explain good construction practices, which will prevent or minimize buckling. Use each complaint as an opportunity to educate users and forestall future complaints.

Buckling

This develops when a restrained panel (i.e., fastened to a framing member) is contorted or deformed between supports, either along its length or across its width. This checklist should help you handle buckling complaints:

Improper panel spacing: Ask how the panels were applied. Let the customer do the talking. Panel spacing is critical because panels need room to expand when they absorb moisture. If they're butted up tight during application, they may buckle. Improper spacing is not the only cause of buckling, but it's the most common. There may be other contributing factors. Generally, panels should be spaced l/8".

. Fastener spacing, type and size; Under ordinary construction conditions, nailing according to APA recommendations keeps panels flat. But if nail spacing is too wide, panels may rise off supports, giving the appearance of buckling. If finish materials are in place, a check of the nailing is difficult. "Missed" nailing is obvious, however. A business card inserted at the panel/support interface can often help you determine nail spacing.

Twisted, improperly aligned, or "high-low" framing members or trusses: These conditions can contribute to "waviness," or the appearance of buckling. Even collar beams must be checked to determine if their corners have been cut off flush with the slope of the rafters. If not, roof panels will "hump" at those points.

. Improper ventilation: Evidence includes rusty nails, mold, waterstained panels, mildew, water droplets or ice particles on sheathing, insulation-clogged vents. inoperative power vents and moist or water-stained insulation. Bathroom and kitchen vents should never discharge into attics. See Technical Note X485, Condensation Causes & Control:Technical Note

D48 I, Buckling of Wood Structural

Panel Sheathing, and Technical Note F4lO, Buckling of Wood-Based Panel Siding, for correcting buckling and ventilation problems.

Warping

Distinct from buckling, warping refers only to unattached panels. Three conditions of shape distortion constitute warping: cupping (when the axis of deformation is parallel to face grain); bowing (when the axis of deformation is perpendicular to face grain), and twisting (when one corner of a panel is bent out of the flat surface plane).

Warping can be prevented by proper panel storage, especially by cutting the bands on bundles stored outdoors or exposed to moisture, by storing panels on three or preferably more evenly spaced stringers, and by weighting down the top panel in a stack. Proper attachment of the panels to framing will almost always pull a warped panel flat. Consequently, the ultimate performance of the panel is normally not compromised. See APA Builder Tips U450, Storage and Handling of APA Trademarked Pane I s, for recommendations.

Thickness Swelling

OSB panels exposed to moisture conditions for extended periods may exhibit irreversible thickness swelling, most typically near panel edges or ends, but also occasionally throughout the field of the panel if the exposure is severe. Panel structural tests show that such swelling does not result in a loss of panel structural capacity (bending stiffness or strength, or diaphragm, shear wall or wall bracing capacity) after the panel dries to in-service moisture conditions

Heavyweight roofing (laminated asphalt shingles, cement tiles, or wood shingles or shakes) and siding can mask surface uneveness that results from thickness swelling, whereas thin or flexible materials may telegraph panel joints or substrate irregularity. More detailed information is available in APA Builder Tips N335, Proper Installation of APA Rated Sheathing for Roof Applications.

Floor surface unevenness may result in telegraphing panel joints through finish flooring, may cause cracks over floor panel joints with rigid, brittle flooring materials such as ceramic tile flooring, or may cause squeaks in the underlayment or wood flooring connections to the subfloor.

Ridges or thickness swelling along end and edge joints between panels in the floor deck should be sanded smooth, after the panels have dried to in-service moisture conditions, and panel buckling should be mitigated before installing finish flooring (carpet and pad, hardwood flooring or plywood underlayment, for use under vinyl, ceramic tile, or direct-adhered carpet). More detailed information is available in APA Builder Tips Q300, Steps to Construct a Solid, SqueakFree Floor System, and APA Technical Note R280, APA Performance Rated Panel Subfloors Under Hardwood Flooring.

Surface Flaking

OSB and plywood panels exposed to moisture conditions for extended periods may exhibit a rough, uneven surface that may detract from appearance. Some lifting or flaking of surface strands on OSB also may occur. Panel structural tests show that such surface degradation does not result in a loss of panel structural capacity (bending stiffness or strength, or diaphragm, shear wall or wall bracing capacity) after the panel dries to inservice moisture conditions.

It is not uncommon for structural panels to be exposed to the weather lor a month or more during construction. The surface of the panels often appears rough but the panels generally remain structurally serviceable.

Although in-place inspection is subiective. one method often used to

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"i. j deterrnine if roof or floor pancls are suitable lbr usc aficr crte nde-cl exposLlre to Vucathelin-e is to wulk on thcnt. lf thc pancls lccl solid contpared to cxperiencc with othe r pancls ol'cquir'alent thickness in sirrrilar applications rncl support sptrcing conclitions. thcr errultl he .jtrdrctl i.r\ \itti\lilLl()li. Tlr.' longer the panel is crposccl. thc murc scrutinizing the inspcction shoLrld bc. Only Extclior pancls are intcnclccl lirr ]lcfrnancnt cxposure to thc wcalhcr. anrl cvcn (hcn conrlitions tltitt can cause clccav shoultl bc ltrevcntccl.

Flooring Applications'I'hcsc corrltlaints. includin-q squcaks. nail poppinr. unclcrlavntcnt w'rinklirrg. arrcl unclerlrnntcnl .joint shou -tlrr-ough. olterr lcsult l'r-ont irnplopcr. instlllation. You cun iclcntil'y'thcm with closc obscrvulion uncl stuclr o1' ,\PA -fechnical Notc C-l(r8. I"loot' SqtrcuA.r.' Crrlr.ic.r, .\olttt iott.s & l)re-vtntitttt. APA Urrilclcr Tips S300. lltinitrti:.c Noil l)o1tt'. Q3(X). .!rr7r.r lo (.ott.stt-trtt tt Solitl , Srltteuk Frcc Floor .t.r'.r'1r,rr: R3.10. Pi'r;7rlt' .\'rIet tirttt & Irt.stulltttitttt ol r\PA I'lyyrootl Iltttlcr Itt.ttrtt'rrt. lncl APA l)tita l;ilc L33-i. Itt.stulltttiotr & Itrtpttratirtn o.f Plt trootl 1..! ttdcrltt .trtterrt .f'or Rt.siIicttt lt I t tt tr (- t tt'c t' t t 1q.

Roof Applications

Rool' surlacc unc\ e nncss olterr rcsults ll'onr ridginu carrsecl bl.ntove nrcnt ol cithcl thc lttol'e ovcrin-e. rtoting unclcrlavntcnt. r'isiil insullrtion. or

Thickness Swelling

roof sheathing clr-rring rnoisture or' tenrpcraturc indr-rccd chungcs. Inrlrropcr installation ol' any ol'thesc contponcnts can rcsult tn Liltc\ cliltess. More dctailecl intitrntation is availublc in APA Builcler Tips K-j10. Hotr to illittittti,-.c Ilucklirt,q o.f A:ltlrulr

C tt ttr 7to t i I i ttn S lt i tt.q I c,s. and Nil-5. Pt'oper lttsttt llutiott ol APA R(ttc(l Shcutltittq for RortI A1t1tIictttittrt.r. ltnd Teclinical Notc D-18 | Bttt klittq o.f Wootl Strrrt trtrttl Ptttral SltL'utltirtg.

Siding Applicutiorts

Surl'acc clantirge to sicling or- otltcr crposcd punels can oftcn be rcltaircd in thc I'icld rvithout rentoving thc panels in rluestion. l)cnts or -gougcs can bc lepaircd bt, rcntoving loose uood nlitcrial u itlt a chiscl <lr router and thcn filline uith l t\\o-contpollcltt. hiuh-pcrlirrnrancc rcsin systcm such as uuto hoclr, ltuttr , Blistcrs can often be lcpairccl b1 injccting an aclhcsive irnil |ch()n(lin.r Ihr. ilt'cir it) (lUc\ti()lt. Both of thcse rlcthods ulc clcscribcd in Tcchnicrrl Notc .lfl05. l:ialtl lleltuir.s ol Pl.tworxl \liltlcri call gro\\ on llnrost anv surlacc il' conditions arc favorablc. -l'echnical Notc l-E0-5. Milrlt,y. l)i.scttlrtrttI ictrr rtl ll'ootl .\itlitt.q. clcscribcs hou rrrildevn dcvclolts. hou, to identil't' i1. anrl rnethods of rcntctvul lund controi Whilc ntildcu, llav bc ttrt.iqltllr. tl (l()c\ llrrl \ilU:r',llrrttlrLe 1,, thc product. It can. how'cr,cr. bc intlicatir c ol' a l)otcntilllr tllntL-uing t.ttoisturt. ltroblenr in thc structurc. Staining o1' puintetl sur'l'aces nta1, occur w'her) watcr-solub lc ri oocl c\tlilcti\cs arc lcucltecl ll'tim tlte wood substratc uncl transpo|tccl to the fini.llr'rl .Lu llrut'. Erlllrr'tire sllrinin!: is oftcn associatccl r.r'ith ultplication of li-cht-colol.cd late.r stains but can be contfollecl through ccrtain pKtcedu|es clcso'ibccl in 'l-cchnical Notc L8 10. Sluirtirrg o.t' L'itti.shas.f t'orrt Wcttt'r"\ttILrItIt ll/ttttd l,rtnrt trye.t. Fot' technicul lrlvicc or'lol ussistance witl'r runusual cornplaints. coltsLllt t,our AI)A liclcl l'cprcscntiiti\e. Renrcrnbcr: ;\l)A licld lcprescntutil,es ure aln'avs trrlrilirhle lt, lutsrtul rlLt(':li()n\ ()n pll;t. els bcaring lhc ntark of'clLrulitl thc Al),\ tlurlenralk.

Information in this article is intended to provide guidance about the serviceability of wood structural panels after a flood. This article is not intended to address potential health and indoor air quality concerns that may arise in this circumstance. This type of information is available from FEMA and the American Red Cross. "Repairing Your Flooded Home" is free from FEMA Publications, Box 70274, Washington, D.C.20024. (Extensive damage may require professional services to assess & repair wood construction.)

Wood Construction & Water

The recent Midwest floods covered an area the size of New Jersey and served up yet another reminder that Mother Nature is in charge. On the positive side. wood construction is durable and will normally be structurally sound after severe water exposure during a flood. Structural plywood and OSB used in floors. walls and roofs are made with water-resistant adhesives that retain their strength when wet. Although the panels will be rougher from water exposure, they are still structurally sound. Saturated panels will feel less stiff than those in a dry condition. Once the panels are dry, strength typically returns and only minor repairs may be necessary.

Note that some plywood panels manufactured prior to about 1972 for interior use may contain adhesives which are not fully water-resistant. These panels can be identified by the term "Interior" in the grademark.

APA Trademark Identification

To tell if your APA plywood has water-resistant adhesives. look for the

APA trademark. APA is the quality assurance agency that many wood structural panel manufacturers use. Older plywood may bear the DFPA trademark (APA's original name was the Douglas Fir Plywood Association). The trademarks will typically be in black ink printed in one or more places on one side of the pancl. The trademarks on APA plywood with water-resistant adhesives will contain the words "Exposure l" or "Exterior". OSB is made with water-resistant adhesives and will also say "Exposure 1" (or "Exterior" for siding).

Fungal Decay Prevention

Once flood water recedes, fungal decay organisms are presented with an ideal moisture condition. So. it is important that the wood dry as soon as possible to ensure that the wood decay does not affect structural capacity. How to preserve sound structures:

1. Clean out all mud and debris in contact with panels, studs, joists and beams. This will allow wood to dry and permit inspection for structural damage.

2. Remove carpeting, pad and vinyl-vital to allow the panels to dry.

3. Remove wet interior finish (such as wallboard) from walls, remove wet insulation, and clean out any mud and debris, encouraging free air circulation to speed the drying process.

4. Remove wet insulation from crawl spaces (and the attic too, if wet).

5. Remove standing water from crawl spaces. Standing water will prevent floors from drying.

6. Open up any other wet cavities to allow air to circulate freely.

7. Finally, make every effort possible to speed the drying process.

Drying speed is relative to the thickness of the wood being dried, the humidity, the temperature, and the amount of air circulation. Heating the structure, if possible, will greatly speed drying. Use fans and dehumidifiers to help move the air. If heat or dehumidifiers are not available, open all doors and windows to encourage air circulation. Depending on conditions, the drying process can take from a week or two to several months.

How to Tell If the Panels Are Dry

The use of a moisture meter is the easiest way to determine moisture content. Panels are dry when the moisture content is 15Vo or less, and usually safe from the threat of decay when 207o or less.

Odor & Appearance

Mud may contain sewage or microorganisms. To minimize the possibility of odor problems, hose out all wall cavities and connection joints, such as between wall studs and bottom plates. Other common causes of odor are mold and mildew. To minimize this potential, thoroughly dry all concealed spaces.

Panels won't look as good as when they were new, but they should be serviceable. Because they are wood products, both plywood and OSB will swell, especially around the edges, and the surface will become uneven.

Localized blistering of plywood may be evident. (Raised or blistered veneer over knotholes and core gaps in the outer veneer of plywood aren't delamination. A core gap is an open veneer joint extending partially or completely through the interior of a panel.)

What About Buckling?

Floor panels may have expanded and buckled out of plane between supports. There are two ways your customer can remedy buckling:

Run a circular saw (set to the panel thickness) along the panel joints. This is called kerfing, and will help relieve the pressure that causes buckling. If tongue-and-groove edges are cut, they must be blocked from underneath. or a layer of APA underlayment must be installed over the top with the underlayment joints offset from the subfloor joints. However, kerfing and drying may not completely remedy buckling.

A second remedy involves installing blocking under the buckled portions of the floor to push the panels flat again. Follow these steps:

1. Enter the home's crawlspace or basement.

2. Identify the buckled area from underneath and measure the distance between the two joists that support the buckled floor section.

WATER can leave oanels discolored with uneven surJaces or minor blisterino. but once the panels are dry, strength typiclily returns and only minor repairs may be necessary.

3. Cut a piece of lumber that is the same dimension as the floor joists (i.e., for a 2xl0 joist, cut a "block" from another 2x10).

4. Nail this support block to joists undemeath the swollen panel joint.

5. Go upstairs and "push" the panel flat again by nailing it to the block.

Rough Floor Surface & Squeaks

It may be possible for your customer to sand the panel face and edges with a commercial sander. Installing a layer of APA underlayment over the top usually will correct the problem. Offset all edges and nail to the exist- ing panels with ring-shank nails.

Floor squeaks may arise from loose space created around nails in the floor panels. This is a result of the swelling and shrinking the panels experience in the wet/dry cycle. To combat squeaks, re-nail with ring-shank nails after the panels and lumber are dry. Squeaks may also arise in the crossblocking or bridging between floor joists and between walls and floors. Precautionary re-nailing at those points may be advisable if they will be inaccessible after the renovation.

Is The Plywood Delaminated?

Delamination is a separation of the individual "plies" or veneers in plywood. This condition is not common. Dry delaminated floor panels may feel soft or spongy when stepped on. The face ply may appear wrinkled. If you suspect delamination, walk over the areas of concern, after the plywood is dry. Panels with exceptionally soft spots may need replacement.

Localized swelling, or blistering over knotholes and core gaps. is not delamination and does not compromise the structural integrity of the panel. If necessary, blisters over knotholes may be repaired by injecting slue under the affected areas.

* Fir Sanded

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(Available in any combination)

Panel 32'

Thickness.... ....1 1 4", 1 1 132", 1 5/32"

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Fu ll thickness available

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(Available in any combination)

Thickness..... ...1 14", 3/8", 1 /2" 418", 314", 1"

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Si2e................4x8, 4x9, 4x1 0 5x8,5x9,5x10

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StructuralSheathing

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1 12".....................4x8, 4x9 & 4x1 0

5/8".....................4x8, 4x9 & 4x1 0

3/4".....................4x8, 4x9 & 4x1 0

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Specialty Applications

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