WATER INTRUSION SIDING. 1 Damage in Residential Walls from Construction Defects and Water 2 TYPES OF CONSTRUCTION DEFECTS

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1 1 Damage in Residential Walls from Construction Defects and Water Intrusion: Old and New Issues George Tsongas, Ph.D., P.E. Consulting Engineer and Building Scientist Professor Emeritus of Mechanical Engineering Portland State University 2 TYPES OF CONSTRUCTION DEFECTS! Improper or poor design! Lack of sufficient details! Improper installation of components! Not following installation instructions! Sloppy construction! Lack of attention to detail! Lack of sufficient training or supervision! Poorly designed or manufactured components! L-P siding, EIFS, fire retardant treated plywood! Lack of - or insufficient - maintenance 3 ONE OF THE MAJOR PROBLEMS WITH CONSTRUCTION DEFECTS: WATER INTRUSION! Defects can allow excessive water entry into building envelope components! Many construction defects cause wall component moisture-related damage! Siding buckling and swelling, mold and decay, gypsum sheathing & WRB deterioration 4 PROBLEM #1: SIDING WAVINESS AND BUCKLING! Unsightly deformation of siding out of plane of the wall! Usually occurs during first year after construction! Siding still functions and keeps water out! Cause #1: by elongation of siding in length direction! Elongation caused by moisture content increase! From dry summer to wet winter condition! Common in all wood products, natural or composite! Cause #2: siding following waviness of sheathing or studs 5 WHEN DOES BUCKLING NOT OCCUR?! Does not occur when siding nailed to studs spaced at 16 and studs are not warped, crooked or bowed! Siding sufficiently restrained by such proper nailing! Studs spaced 16 o.c. is standard construction 6 WHEN DOES BUCKLING OCCUR?! Siding nailed at 16 o.c., but siding gets excessively wet on its backside due to water leaks (construction defects)! Siding nailed at greater than 16 on center! Larger stud spacings do not provide enough restraint! Sometimes caused by nails missing studs ( shiners )! Sometimes caused by missing nails! Exacerbated by siding wetted on backside due to leaks! Exacerbated by lack of required vapor barrier! Siding follows wavy sheathing or warped studs! Siding relative thin (e.g., fiber-cement lap) 7 PHOTO: BUCKLING WITH NAILING AT 16 O.C. WITH BACKSIDE WETTING 8 PHOTO: BUCKLING WITH NAILING AT GREATER THAN 16 O.C. 9 PHOTO: STUD SPACING OFTEN UNEVEN AND GREATER THAN 16 O.C. 10 PHOTO: BUCKLING WITH NAILING GREATER THAN 16 DUE TO NAILS MISSING STUDS 11 PHOTO: BUCKLED T1-11 PLYWOOD PANEL SIDING DUE TO IMPROPER NAILING 12 PHOTO: WAVY CEDAR SIDING 13 PHOTO: BUCKLED CEDAR SHINGLE SIDING 14 PHOTO: WAVY SIDING FOLLOWING WETTED & WARPED PLYWOOD SHEATHING 15 PHOTO: WARPED PLYWOOD WETTED BY WINDOW LEAK ABOVE THAT CAUSED BUCKLED SIDING 16 PHOTO: WAVY FIBER-CEMENT SIDING 17 PHOTO: CROOKED/BOWED/WARPED STUDS CAUSING BUCKLED SIDING 18 PHOTO: PSU LAB BUCKLING TEST SETUP

2 19 PORTLAND STATE UNIVERSITY (PSU) TESTS OF HARDBOARD SIDING BUCKLING! Sprayed water on shiplap siding of test walls for 8 weeks to simulate % outdoor relative humidity condition! Siding nailed to studs spaced at 16, 24, and 32! Siding nailed at 16 did not buckle or deform at all! Siding nailed at 24 & 32 did deform out of plane 20 PROBLEM #2: SIDING SWELLING! Two types:! Drip edge swelling! Face swelling (sometimes observed as swelling or dimpling around nail heads) 21 SIDING DRIP EDGE SWELLING! Edge swelling occurs near bottom edges of siding! Typically occurs with composite wood siding products! Water drops hang on drip edge with thin or no paint! Then liquid water absorbed by capillary action up into the fiber of the siding drip edge! Water absorption causes the siding to swell locally at drip edge 22 SIDING DRIP EDGE SWELLING ALMOST ALWAYS CAUSED BY THIN OR NONEXISTENT DRIP EDGE PAINT! Very slow process---typically takes years for swelling to become noticeable! Typically occurs due to poor spray painting of the siding drip edges! Violation of siding application instructions! Typically does not result in siding decay, except:! Lowest siding course near grade or concrete! Any course of older OSB siding 23 PHOTO: LACK OF DRIP EDGE PAINT 24 PHOTO: DRIP EDGE SWELLING & DECAY 25 PHOTO: NATURAL WOOD TRIM UNPAINTED CUT END DECAY/SPLITTING 26 PHOTO: VERTICAL CORNER TRIM WITH AND WITHOUT CUT EDGE SWELLING/DECAY 27 SIDING FACE SWELLING ALMOST ALWAYS CAUSED BY WETTING OF SIDING BACKSIDE! Most typically occurs due to absorption of large amounts of liquid water on the backside of composite wood siding products! Water gets there from leaks caused by construction errors! Typically much more water gets into the siding than with poor drip edge paint! Much more common cause of siding swelling, bowing & decay! Swelling leads to micro-cracking of drip edge paint! Note: liquid water does not migrate through proper face paint 28 PHOTO: FACE SWELLING ( DIMPLING AROUND NAIL HEADS) 29 PHOTO: MICRO-CRACKING OF THE SIDING DRIP EDGE 30 PHOTO: PSU FACE SWELLING LEAK TEST 31 PSU WALL LEAK TEST RESULTS! After only two weeks of daily intermittent dripping the following was observed:! Definite bowing of siding at the drip edge between nails (16 o.c.)! Siding swelling! Micro-cracking of the drip edge paint 32 PSU WALL LEAK TEST CONCLUSIONS! Lab test results duplicated siding deterioration observed in the field! Verified cause of siding swelling, bowing between nail heads, and micro-cracking of drip edge paint observed in the field! Due to water being absorbed on siding backside 33 PHOTO: PSU LEAK TEST SIDING BOWING 34 PHOTO: SIDING BOWING BETWEEN NAIL HEADS 35 BE CAREFUL ABOUT BLAMING CONTRACTORS FOR OVERDRIVEN NAILS IN SIDING! Can be caused by swelling of OSB sheathing! OSB can naturally swell up to 30% in thickness as a result of normal swings in air s relative humidity! Can result in 20% irreversible thickness swell! Liquid water need not be present! Overdriven nails are not always really overdriven or caused by improper nailing 36 PROBLEM #3: WOOD DECAY (ROT)! Caused by growth of decay fungi! Requirements for growth of wood decay fungi:! Abnormally wet wood (i.e., soaking wet)! Moisture content greater than 25-30% Wood normally much drier (6-18%)! Warm wood temperature! Optimally F

3 ! Little or no growth below 50 F! Wood typically not so wet during warm weather 37 WHEN DOES WOOD DECAY?! Typically occurs only when siding is excessively wet during warm weather on unpainted or poorly painted drip edges! Occurs often on lowest siding courses due to repeated, long term wet contact (such as with concrete or soil), splash back, or sprinkler wetting! Also occurs commonly when siding or other wall components get excessively wet due to leakage of liquid water behind siding due to construction errors 38 HOW LONG DOES IT TAKE FOR DECAY TO BECOME VISIBLE?! Under the right conditions, decay can start microscopically in a matter of hours or days! Under optimum conditions, decay fungal growth can become visible in a month or so! More often, decay takes years to progress to the point where it is clearly visible! Note: decay can produce significant strength loss much more rapidly than weight loss (clearly visible) 39 COMMON DECAY LOCATIONS! Window openings, particularly at corners! Typically most frequent problems! Intersection of walls with floors or slab-on-grade! Intersection of walls with exterior balconies/walkways! Siding lowest course too close to soil or concrete! Siding lowest courses wetted by sprinkler spray! Handrail connections; rail caps (especially fences)! Belly bands and other plant-on trim! Confined rakes (gutter ends) 40 PHOTO: SIDING DECAY BELOW LEAKING WINDOW TRIM 41 PHOTO: OSB SHEATHING DECAY BELOW LEAKING DEFECTIVE WINDOWS 42 PHOTO: SIDING DECAY CAUSED BY CONTACT WITH WET CONCRETE 43 PHOTO: DECAYED SILL TRIM (SIMILAR TO BELLY BAND) 44 PHOTO: SIDING DECAY BELOW IMPROPERLY INSTALLED DECK 45 PHOTO: STAIRWAY LANDING LEAKING INTO WALL & OUT BETWEEN SIDING LAPS 46 PHOTO: DECAY BELOW STAIRWAY LANDING LEAK 47 PHOTO: SIDING DECAY CAUSED BY WATER LEAK BEHIND THE SIDING ON EXTERIOR BALCONY 48 PHOTO: DECAY BELOW BALCONY LATTICE 49 PHOTO: RAILING DECAY CAUSED BY MITER JOINT WATER LEAK 50 PHOTO: DECAY AT HANDRAIL CONNECTION TO WALL 51 PHOTO: CEDAR SIDING DECAY CAUSED BY EXCESSIVE WETTING AT PRIVACY FENCE RAIL CAP CONNECTION 52 PHOTO: DAMAGE FROM GUTTER END LEAK 53 PHOTO: TRIM DECAY CAUSED BY POOR DESIGN 54 PHOTO: MAINTENANCE ISSUE---SIDING WETTED BY ERRANT SPRINKLER SPRAY 55 PHOTO: WHITE MYCELIUM ON COMMERCIAL BUILDING OSB ROOF SHEATHING 56 PROBLEM #4: MOLD GROWTH! Mold can grow on a surface when it is wetted! Such as by leaks into walls from outside or contact with or proximity to wet concrete 57 PHOTO: CEILING & WALL MOLD FROM CONSTRUCTION ERROR (SCUPPER LEAK INTO WALL) 58 PHOTO: MOLD ON COMMERCIAL BUILDING CEILING TILE DUE TO LEAK ABOVE 59 PROBLEM #5: GYPSUM SHEATHING & WRB DETERIORATION! Non wood materials do not decay! Gypsum does not decay, but does deteriorate! Gypsum sheathing softens & crumbles! WRB materials can deteriorate without decay! Materials can disintegrate when wetted 60 PHOTO: DETERIORATED GYPSUM SHEATHING DUE TO POOR EDGE SEALING 61 TYPES OF WATER ENTRY AND MOVEMENT MECHANISMS IN WALLS! Those that do not cause decay or other damage! Water entry amounts are not excessive

4 ! Incidental water naturally dries out! Those that cause damage to wall components! Water entry amounts are excessive 62 POSSIBLE WAYS WATER COULD ENTER WALL CAVITIES WITH MINIMAL, IF ANY, ADVERSE EFFECT! Liquid water through siding nail holes! Liquid or vapor water through siding exterior paint! Rain wind-blown up in between siding laps! Wicking liquid up into bottom drip edge of siding! Typically not a problem with well-painted drip edges! Wicking liquid water up between siding laps! Not a problem for some types of siding 63 SCHEMATIC: WATER ENTRY BY CAPILLARY WICKING UP BETWEEN SIDING LAPS 64 CAPILLARY WICKING BETWEEN SIDING LAPS! Often proposed without basis! Never confirmed by any scientific tests anywhere in the world! Except for PSU laboratory cedar siding spray tests 65 PHOTO: PSU LABORATORY WICKING SPRAY TEST SETUP 66 PORTLAND STATE UNIVERSITY LABORATORY SPRAY WICKING AND OTHER TEST CONCLUSIONS! Capillary wicking up between siding laps:! Does not occur for hardboard and fiber-cement siding! Proven in numerous laboratory tests! Does occur with cedar siding in spray wicking tests! Even when back primed! Likely causes staining and paint adhesion problems 67 PHOTO: DETERIORATED, WATER-LOGGED PAINT ON CEDAR SIDING 68 WATER STAINING OF BACKSIDE OF SIDING OFTEN GIVEN AS PROOF OF WICKING UP BETWEEN SIDING LAPS! But, staining of backside caused by water leaking into the backside of the siding due to construction errors and migrating along drip edge! Numerous examples of such leaks and subsequent staining! Not due to wicking up between siding laps 69 PHOTO: SIDING WHERE BACKSIDE DRIP EDGE WATER STAINED 70 PHOTO: SIDING BACKSIDE WATER STAINING FROM DEFECT LEAK 71 WAYS WATER DOES ENTER WALL CAVITIES AND CAUSES DAMAGE! Liquid water leaking behind siding (e.g., around windows)! Includes moving through weather-resistant barriers! Liquid water wicking into gypsum sheathing behind siding! Liquid water wicking up into bottom drip edges of siding! With poorly-painted or unpainted drip edges! Siding contact with concrete, or siding too close to soil and drip edges with little or no paint! Rain splash back; sprinkler wetting! Water vapor migrating into walls from inside the house! Solar-driven moisture transfer from siding into sheathing! Indoor moisture entry from or through wet concrete floors! Moisture entry into walls from wet lumber 72 LIQUID WATER LEAKING BEHIND SIDING USUALLY DUE TO CONSTRUCTION ERRORS! Leaks into walls can be a huge source of liquid water behind the siding! Liquid water that gets to the siding s backside is more readily trapped and absorbed! Windows commonly leak and flashing and sealant errors often occur that allow water entry into walls 73 SURPRISINGLY LARGE WATER LEAK FLOW RATES DUE TO CONSTRUCTION ERRORS! Small openings are not uncommon in building construction! Calculated and lab test proven water flow rates through small horizontal leak openings:! 1/8 inch diameter hole: 2 gallons per hour! Obviously not all openings are horizontal 74 COMMON LEAK LOCATIONS! Window openings, particularly at corner trim joints! Typically most frequent problems! Intersection of walls with floors or slab-on-grade! Intersection of walls with exterior balconies/walkways! Siding lowest course too close to soil or concrete! Siding lowest courses wetted by sprinkler spray! Handrail connections; rail caps (especially fences)! Belly bands and other plant-on trim! Confined rakes (gutter ends)

5 75 PHOTO: SEVERE STRUCTURAL DECAY FROM SMALL ROOF FLASHING LEAK 76 PHOTO: SIDING DECAY DUE TO STAIRCASE--SIDING JOINT LEAK 77 PHOTO: WATER LEAK HOLE AT STAIR LANDING BEAM PENETRATION 78 PHOTO: WALL SIDING WITH LEAK SITE AT 3 RD STORY WALKWAY 79 PHOTO: THIRD STORY LEAK SITE 80 PHOTO: CONSEQUENT MOLD & DETERIORATION ON GYPSUM SHEATHING 81 PHOTO: CONSEQUENT MOLD & DECAY ON BACK OF REMOVED SIDING 82 PHOTO: WATER LEAK HOLE (BALCONY TO SUPPORT COLUMN) 83 PHOTO: DECAY DUE TO BALCONY-TO-COLUMN LEAK 84 PHOTO: SIDING DECAY DUE TO BALCONY-TO-COLUMN LEAK 85 AMOUNT OF LIQUID WATER REQUIRED TO CAUSE DECAY! Assume a roughly 16 square foot area of ½ inch thick wood siding or sheathing! Assume a moisture content change from normal (dry) 10% to 30% required to grow decay fungi! Amount of water required that must be absorbed into the wood siding or sheathing just to raise its moisture content that amount is about 1 gallon!! Laboratory wall leak drainage test results suggest that at least 10 times as much water drains out of a wall as is absorbed by the wall components! Thus, water leaks into walls must be relatively large (many gallons) when decay occurs 86 THE MOST COMMON LOCATION OF DAMAGE IN BUILDINGS IS AROUND WINDOWS! Damage to siding and paint! Damage to window trim! Damage to WRB! Damage to gypsum sheathing! Damage to structural sheathing (OSB or plywood)! Damage to framing 87 PHOTO: SIDING & TRIM DECAY CAUSED BY A WINDOW HEAD TRIM LEAK 88 PHOTO: WATER LEAK HOLE AT UNSEALED WINDOW HEAD TRIM 89 PHOTO: MORE WINDOW LEAK SITES 90 PHOTO: OTHER WINDOW LEAK SITES 91 PHOTO: SIDING & TRIM DECAY CAUSED BY WINDOW TRIM LEAKS 92 LAB WALL FLASHING LEAKAGE TESTS! Walls tested with windows properly and improperly flashed and caulked! To determine if construction errors allowed water intrusion that caused resultant damage! Followed ASTM E 331 standard test protocol! Full scale walls sprayed in a laboratory for 3 hours to simulate severe wind-driven rain 93 PHOTO: LABORATORY WINDOW FLASHING LEAKAGE TEST SETUP 94 PHOTO: WINDOW FLASHING LEAKAGE TEST RESULT (WORST CASE) 95 PHOTO: WALL CAVITY DAMAGE CAUSED BY WINDOW LEAK (NO SILL TRIM SEALANT) 96 PHOTO: SIDING AND TRIM DECAY DUE TO LACK OF SEALANT 97 PHOTO: WINDOW LEAK DETERIORATION 98 PHOTO: WINDOW LEAK DRYWALL DAMAGE 99 ONE OF THE BIGGEST WINDOW LEAK CULPRITS: VINYL WINDOW FRAMES! Vinyl has a very large coefficient of thermal expansion! In our climate a 6 foot long vinyl window frame changes length about 1/8 inch between seasons!! Joints between frame & trim open up! Joints between jamb & sill trim are forced open! Even when joints caulked, they open up Typically thin caulk installed between the frame and window trim simply cannot flex that amount & cracks/breaks 100 PHOTO: DAMAGE CAUSED BY WINDOW LEAK (NO FRAME TO TRIM SEALANT) 101 PHOTO: DAMAGE FROM UNSEALED WINDOW FRAME TO TRIM JOINTS 102 PHOTO: WINDOW LEAKS FROM BEHIND MANY FIBER-CEMENT SIDING LAPS 103 PHOTO: DAMAGE DUE TO SEEPAGE AT UNSEALED WINDOW TRIM MITER JOINTS 104 PHOTO: WINDOW JAMB-SILL TRIM JOINT LEAK (NO SEALANT) EFFECT

6 105 ALL THE EMPHASIS ON INSTALLING SELF-ADHERING WINDOW FLASHING AROUND WINDOWS HAS CREATED A SENSE OF FALSE SECURITY! Water enters walls where there is no sealant or improperly installed sealant! Between window trim jamb & sill pieces! Between window frame & trim! Water that has entered those locations flows past the self-adhered flashing & damages the sheathing 106 RESOLVING LIQUID WATER LEAKAGE AROUND AND THROUGH WINDOWS! Water leakage obviously occurs around window trim! Siding and trim damage common around windows! Designers and builders should take the approach that any window may allow water through at some time and design to handle that water! Avoid vinyl windows fiberglass frames much better! Install window frame to trim caulk at all joints with minimum ¼ caulk width & backer rod applied behind! Install proper window sill flashing with back dam! Improved wall water drainage is crucial! Building paper or housewrap alone is not enough 107 LATERAL WATER MIGRATION: DOES IT OCCUR AND MAKE MATTERS WORSE?! Siding and trim deterioration is often obvious near or below a known water leak entry point! What about siding deterioration well away from the point source?! Often observed! Is it related to the known leak source? 108 PHOTO: PSU LATERAL WATER MIGRATION LAB TEST SETUP 109 PHOTO: LATERAL WATER MIGRATION STAINING BEHIND HARDBOARD SIDING 110 PHOTO: LATERAL WATER MIGRATION TESTS WITH REDWOOD SIDING 111 LATERAL WATER MIGRATION TEST CONCLUSIONS! Once water leaks behind siding it can readily move laterally to locations well away from the leak source point! Such migration not limited to one type of siding! If sufficient water leaks into a wall, siding, sheathing, and trim deterioration can be expected just about anywhere in the wall---even well away from the leak source point 112 PHOTO: LATERAL WATER MIGRATION 113 PHOTO: LATERAL WATER MIGRATION 114 PHOTO: LATERAL WATER MIGRATION 115 PHOTO: LATERAL WATER MIGRATION 116 RAIN WATER LEAKS ARE A MAJOR CAUSE OF HIDDEN MOLD AND DECAY! Leaks are not uncommon in new construction! Caused by numerous types of construction errors! Leaks can result in considerable wetting of materials! Wet building materials do not always dry out quickly! Wall components can take many months to dry! Based on computer simulation! There is ample time for fungal growth 117 COMPUTER MODELING DRYING RESULTS 118 WATER ENTRY BY WICKING LIQUID UP INTO GYPSUM SHEATHING! In multifamily housing gypsum sheathing often exists behind siding for fire protection reasons! Gypsum sheathing behind siding readily wicks water up from its base that is wetted by:! Ponding water from rain or spray washing! Rain or spray washing splash back! Misdirected sprinklers! Wet concrete base that gypsum sheathing sits on 119 WET GYPSUM SHEATHING WICKS WATER INTO SIDING OR STRUCTURAL SHEATHING SURROUNDING IT! Leads to moisture damage to those wall components, including mold and decay! In addition, gypsum sheathing deteriorates 120 PHOTO: MOLD & DETERIORATION OF BUILDING PAPER ON WETTED WALL 121 PHOTO: MOLD ON GYPSUM SHEATHING & MOLDY, DECAYED OSB SHEATHING 122 SCHEMATIC: PSU LABORATORY VERTICAL WICKING TEST SETUP 123 PHOTO: PSU LAB VERTICAL WICKING TEST SETUP 124 PSU LABORATORY VERTICAL WICKING TEST RESULTS! In 20 days water wicked up gypsum sheathing about 4 feet! Wicked up 10 inches in first day

7 ! In 20 days water wicked up hardboard siding ¼ - 2¼ inches! Wetted gypsum sheathing caused deterioration of plywood & OSB sheathing 125 PHOTO: PSU TEST DAMAGE TO PLYWOOD SHEATHING FROM WETTED GYPSUM 126 WATER ENTRY BY WICKING UP INTO SIDING OR SHEATHING BOTTOM DRIP EDGE 127 PHOTO: SIDING DRIP EDGE SWELLING CAUSED BY WICKING INTO EDGE 128 PHOTO: SHEATHING DAMAGE FROM RAIN SPLASHBACK WHERE BOTTOM EDGE OF SHEATHING EXPOSED 129 PAST PROBLEMS WITH OSB SIDING! OSB siding had design and manufacturing problems! Drip edge was hard to seal and prone to swelling allowed water entry by capillary wicking into siding! Exterior face surface was a vapor retarder! Created by resin-coated kraft paper face! Trapped liquid water wicking into drip edge! Kept wetted OSB from drying out! Combination led to swelling, cracking, & decay! Old OSB siding was inherently defective in my opinion 130 PHOTO: OLD OSB LAP SIDING WITH DECAY FUNGI GROWING FROM DRIP EDGES 131 PHOTO: OLD OSB PANEL SIDING WITH DECAY FUNGI GROWING FROM GROOVES 132 POSSIBLE FUTURE PROBLEM WITH FIBER-CEMENT SIDING! Lack of paint or thin paint on drip edges could allow significant water to wick into the siding! Fiber-cement siding is highly absorbent! Job site wetting prior to painting could do the same! Solar heating could drive water vapor from the siding into the sheathing & framing! Thus increasing its moisture and causing mold or decay of moisture barriers, sheathing, & framing! Not readily observed from the outside 133 PHOTO: ANOTHER PROBLEM--CRACKED FIBER CEMENT LAP AT BUTT END 134 WATER ENTRY BY SIDING OR SHEATHING CONTACT WITH WET CONCRETE OR SIDING OR SHEATHING TOO CLOSE TO SOIL! Contact with concrete readily wicks liquid water into materials! Poor construction practice! Violation of some siding application instructions! Leads to siding or sheathing decay or deterioration! Building codes and manufacturer s installation instructions require 6 separation of bottom course of siding from soil! Splash back in cases with less than 6 separation has led to siding and sheathing swelling, mold and decay 135 PHOTO: SIDING DECAYED DUE TO CONTACT WITH CONCRETE 136 PHOTO: T1-11 PLYWOOD SIDING DECAYED DUE TO CONTACT WITH WET CONCRETE 137 PHOTO: SIDING DECAY FROM CONTACT WITH WET CONCRETE WALL 138 PHOTO: SIDING TOO CLOSE TO GRADE CAUSING DECAY 139 VAPOR DRIVE: WATER VAPOR MIGRATING INTO WALL CAVITY FROM INDOORS DURING HEATING SEASON! When indoor temperatures are warmer than outdoor conditions, vapor drive is from indoors (warmer) to outdoors (colder) 140 WINTERTIME VAPOR MOVEMENT IN WALLS 141 SOME CLADDINGS ARE VAPOR IMPERMEABLE! Thus they trap water vapor that is normally migrating in winter from the warm indoors to the colder outdoors! Leading to condensation, moisture buildup in the materials behind the siding, and decay! Vapor permeable claddings allow the water vapor to pass through them to the outdoors 142 PAST MOLD & DECAY PROBLEMS WITH OLDER FACE-SEALED EIFS! External Insulated Finish Systems (EIFS) cladding! Also known as synthetic stucco! Lack of drainage capability and inability to dry to the outside with older face-sealed EIFS allowed significant wetting of wall components that led to mold and decay! Jury still out on whether new EIFS drainage systems work! They are designed to help keep walls drier & decay free 143 PHOTO: METAL STUD EIFS WALL MOLD 144 PHOTO: PLYWOOD SHEATHING DECAY IN EIFS FACE-SEALED WALL 145 MOISTURE PROBLEM WITH SOME VINYL SIDING

8 ! Some vinyl siding acts as an excellent vapor retarder on the outside (wrong side) of the wall in cold climates! Traps water behind it and wets moisture barriers, sheathing, and framing! Can cause long term mold & decay problems! Not widely known, since not much vinyl siding gets removed and wall cavities behind it inspected 146 PHOTO: WATER STAINING DAMAGE ON GYPSUM SHEATHING BEHIND VINYL SIDING & HOUSEWRAP 147 PHOTO: DECAY & MOLD DAMAGE ON OSB SHEATHING BEHIND GYPSUM SHEATHING & VINYL SIDING 148 PHOTO: LIQUID WATER DRAINING OUT OF VINYL-SIDED WALL CAVITY 149 PHOTO: DAMAGE TO GYPSUM SHEATHING & TJI BEHIND VINYL SIDING 150 PHOTO: WATER DRIPPING OUT FROM BEHIND VINYL SIDING 151 PHOTO: BACK OF SIDING DRIPPING WET 152 PHOTO: DRIPPING WET BUILDING PAPER 153 PHOTO: DAMAGE TO GYPSUM SHEATHING 154 PHOTO: DRIPPING WET BUILDING PAPER 155 PHOTO: DAMAGED OSB SHEATHING BEHIND VINYL SIDING 156 PHOTO: WATER STAINS ON GYPSUM SHEATHING FROM SIDING CONDENSATION 157 PHOTO: DAMAGE AT RIM JOIST WHERE NO VAPOR BARRIER EXISTS 158 PHOTO: SIDING CROSS-SECTION SHOWING BLOCKED WEEP HOLE 159 INDOOR MOISTURE ENTRY FROM WET CONCRETE SLAB-ON-GRADE FLOORS CAUSE OF MOLD & DECAY IN DWELLINGS! Concrete slab floors in apartments & single family homes! A huge indoor moisture source as the concrete dries! Most severe during first one-two years! Often exacerbated by lack of slab edge sealing! Sand layer below slab can fill with water! Vinyl floors bubble or discolor (turn moldy)! Mold and decay fungi grow on 1 st story lower wall sections and under carpets (stained tack strips)! Mold not found in 2 nd story apartments & rooms 160 PHOTO: MOLD UNDER VINYL FLOOR OVER WET SLAB-ON-GRADE 161 PHOTO: MOLD ON CARPET TACK STRIP AND WALL DUE TO WET CONCRETE FLOOR 162 PHOTO: MOLD ON FLOOR MOLDING IN POORLY HEATED CLOSET WITH NEW WET CONCRETE 163 PHOTO: LANDSCAPING PROBLEM---IMPROPER GRADING/BERMING 164 PHOTO: EFFECT OF LANDSCAPING ERRORS---WET, MOLDY CARPETS 165 PHOTO: CRAWL SPACE CONCRETE FOUNDATION WITH WATER STAINING 166 MOISTURE ENTRY INTO WALLS FROM WET CONSTRUCTION MATERIALS! Wet green lumber (often stored outside in lumber yard)! Sometimes with black mold on it! Pond-dried lumber (left stored on site out in the rain)! Lumber in place in home wetted before roof cover-in! Often results in serious mold growth! Even on kiln-dried lumber! Mold from such wet materials becoming a serious issue to prospective homeowners in new construction 167 PHOTO: BLACK MOLD ON A VERTICAL STUD IN AN OPENED WALL CAVITY 168 PHOTO: MOLD ON WALL FRAMING EXPOSED TO THE WEATHER 169 INFLUENCE OF TYPE OF MOISTURE BARRIER ON DRAINAGE AND DAMAGE! PSU lab tests for DuPont to compare drainage of different housewraps and building papers under simulated wall leak conditions (between siding & paper/wrap)! Best drainage & least damage with furring strips (rain screen)! Next best with groove-textured housewrap! Next best with conventional housewrap! Worst by far with Grade D building paper & No. 15 felt! OSB sheathing moldy & decayed at end of 4 month test in No. 15 felt case (no decay in other cases)

9 170 PHOTO: PSU LEAK DRAINAGE TEST SETUP 171 PHOTO: WATER STAINING & MOLD ON OUTSIDE OF OSB SHEATHING 172 COMMON MYTH: BUILDING PAPERS AND HOUSEWRAPS WORK WELL AT DRAINING WATER THAT LEAKS INTO WALLS! While most of the water that might leak into a wall does, in fact, drain out, a small fraction is absorbed by the back of the siding and the other wall components! Not all the water leaking into a wall drains out at the bottom of the building paper or housewrap! That small fraction that is retained in the wall can result in elevated moisture contents that lead to deterioration such as mold and decay 173 PHOTO: IMPROPER HOUSEWRAP LAPPING/SEQUENCING 174 CONCLUSIONS FROM MY 30+ YEARS OF SITE OBSERVATIONS! The vast majority of walls are usually performing just fine! Wall components are sometimes deteriorated in a few locations throughout a project! Problems occur repetitively at several typical locations! Problems stem from certain design, construction, material & maintenance practices! Not following component installation instructions! Poor design and construction practices! Poor maintenance! Sometimes due to use of defective products 175 WAYS TO KEEP WALLS DRIER AND LIMIT YOUR LIABILITY! Work hard at avoiding construction errors! Better training is essential! The devil is in the details!! Proper flashing and sealing of all kinds is critical 176 BE PROACTIVE ABOUT INSTALLING WINDOWSAND THEIR TRIM! Properly install windows and doors and their trim! Follow ASTM E 2112 (Standard Practice for Installation of Exterior Windows, Doors and Skylights), published in September The largest ASTM standard ever published, E 2112 provides detailed and comprehensive step-by-step protocols for installing and flashing residential and light commercial windows and doors! ASTM E 2112 has been largely ignored, but shouldn t be! Don t let anyone without proper training install windows 177 PHOTO: INSTALL BACKER ROD AND CAULK BETWEEN TRIM AND WINDOW FRAME 178 WAYS TO LIMIT YOUR LIABILITY: THE SINGLE MOST IMPORTANT WALL CONSTRUCTION ITEM! Build walls using a rain screen wall drainage approach:! Provide an air space behind the siding so there is true drainage for unanticipated water leaks! Helps avoid mold and decay problems! Numerous workable, cost effective approaches! Avoid the use of building papers or regular housewraps alone without a drainage space or drainage design IRC (INTERNATIONAL RESIDENTIAL CODE) MODEL CODE WALL DRAINAGE REQUIREMENT! Adopted as 2008 Oregon Residential Specialty Code! Amended Section : Exterior wall envelope. To promote building durability, the exterior wall envelope shall be installed in such a manner that water that enters the assembly can drain to the exterior. The envelope shall consist of an exterior veneer, a WRB, a minimum 1/8 space between the WRB and the cladding (or an enhanced WRB), and integrated flashings! Fastening siding directly to the face of a smooth weather barrier (WRB) is no longer acceptable 180 WAYS TO PROVIDE WALL DRAINAGE! Install furring strips over housewrap or building paper! Provides best combination of drainage & drying! Widely used in new Canadian construction! Required in Vancouver, BC for many years! Install drainage type housewrap (at a minimum)! Install drainage mat over conventional housewrap 181 SCHEMATIC: RAINSCREEN APPROACH USING FURRING STRIPS (STRAPPING) 182 PHOTO: RAIN SCREEN APPROACH TO WALL CLADDING CONSTRUCTION 183 PHOTO: PLASTIC HONEYCOMB BATTENS 184 PHOTO:PLASTIC BATTEN OVER HOUSEWRAP 185 PHOTO: SIDING OVER PLASTIC BATTENS WITH SCREENING 186 PHOTO: SCREENING WRAPPED AROUND PLASTIC BATTENS AT BOTTOM OF WALL 187 RAIN SCREEN WALLS MINIMIZE MOISTURE DAMAGE WITH ALL CLADDING TYPES! Best example: brick cladding with air space behind! Greatly reduces moisture problems with vinyl, fiber cement, metal, and OSB siding as well as stucco cladding! Allows leaks due to construction errors to drain! Siding acting as an exterior vapor retarder no longer a problem

10 ! Allows water vapor migrating from indoors to vent out! Improves paint service life 188 THE END