JJoohhnn LL�� MMeerrrriillll

Persistent fog or frost onwindows� mold on ceilings andwalls� and musty odors are all

signs of moisture problems in thehome� If allowed to persist� theseproblems are not only annoying�but can damage your home — andin some cases� can cause healthproblems�

To solve winter moisture problemsin your home� you must first recog�nize the nature of the problems andunderstand their cause� This publi�cation introduces you to the simplephysics and basic terms associatedwith humidity and condensation�Armed with this basic understand�ing of moisture problems� you willbe better able to solve theproblems yourself or evaluate solu�tions others propose�

Understandinghome moistureMMooiissttuurree tteerrmmssThe following terms are usedthroughout this publication�WWaatteerr vvaappoorr — the gaseous formof water — is the invisible source ofmany home moisture problems�Most air contains some watervapor� or hhuummiiddiittyy� The amount ofwater vapor the air holds dependson these combined factors:■ AAiirr aanndd ssuurrffaaccee tteemmppeerraattuurreess

(dew point)■ MMooiissttuurree aavvaaiillaabbllee (relative

humidity)AAiirr tteemmppeerraattuurree determines howmuch water vapor air can hold� Thewarmer the air� the more watervapor it can hold�RReellaattiivvee hhuummiiddiittyy is a measure thatdescribes the amount of moisturethe air holds relative to the most itcould hold at a given temperature�For example� if the air temperatureis ��° Fahrenheit (F)� a relativehumidity of �� percent means thatair at that temperature containsonly �� percent of the moisture itcould hold�If air temperature then drops from��° F to ��° F� the relative humiditywill climb to nearly �� percent —even though the amount ofmoisture in the air remainsunchanged� This happens becausecolder air cannot hold as muchmoisture as warmer air�

1

Winter HomeMoisture Problems

University of Wisconsin-Extension Cooperative Extension

B���

M A I N T A I N I N G Y O U R H O M E

Frost on your windows?

Mold on your walls?

Keep winter

indoor humidity

at �� to ��

percent�

If air temperature drops stillfurther� from ��° F to ��° F� therelative humidity will be ��percent� At this point� some watervapor in the air will begin tocondense to liquid water becausethe air can no longer contain it�The ddeeww ppooiinntt is the temperatureto which air with a given humiditylevel must cool for water vapor tocondense to liquid� In this case���° F is the dew point�In figure � temperatures in the leftcolumn and relative humidity levelsin the middle column representsome common combinations�Temperatures in the right columnshow how much air with thathumidity level would have to coolto reach its ddeeww ppooiinntt — the pointat which condensation occurs�CCoonnddeennssaattiioonn leaves fog or frost onwindows in winter� and water onwalls and other household surfaces�This results from moist air coming incontact with surfaces that are colderthan its dew point temperature�

Water condenses on basementwalls and floors in summer becausethese surfaces are often cooler thansummer dew points�

Winter relativehumidityIn cold climates� the ideal indoorrelative humidity level needs tobalance between human comfortand risk of condensation�WWhheenn hhuummiiddiittyy lleevveellss aarree ttoooo llooww��people complain of dryness andstatic electricity� Wood floors andfurniture develop cracks�WWhheenn hhuummiiddiittyy lleevveellss aarree ttoooo hhiigghh��moisture condenses on coldsurfaces�The compromise often recom�mended is to keep relative humiditylevels between �� and �� percentin winter�

Estimatinghumidity levels One of the first steps for diagnos�ing the cause of moisture problemsis to check the humidity level inyour home�You can estimate the relativehumidity in winter by observation�Use the information in figure ��Check your windows for fog orfrost� and compare indoor withoutdoor temperatures for the kindof windows you have (see nextpage)�For example� if you have ddoouubbllee��ggllaazzeedd wwiinnddoowwss�� sseett yyoouurr tthheerrmmoo��ssttaatt aatt ����°° FF�� aanndd ffoogg oorr ffrroossttppeerrssiissttss on bare windows duringthe day when outside temperaturesare �° F or above� rreellaattiivvee hhuummiiddiittyyiiss mmoorree tthhaann ���� ppeerrcceenntt��

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M A I N T A I N I N G Y O U R H O M E

FFiigguurree :: Dew points for common air tempera�ture�relative humidity combinations�

TTeemmppeerraattuurree RReellaattiivvee DDeeww ppooiinntt ((FF))((FFaahhrreennhheeiitt)) hhuummiiddiittyy((��)) ������ RRHH

�° �� �°

��� ��°

��� ��°

��° �� � °

��� ��°

��� ��°

�° �� � °

��� ��°

��� ��°

��° �� �°

��� �°

��� �°

3

If the temperature in your home orin specific rooms is cooler than ��°F� the relative humidity level thatyields persistent condensation ondouble�glazed windows will besomewhat lower�You may not need a more accuratemeasure of humidity than thisestimate�Figure � shows condensation onwindows as affected by outsidetemperature� indoor relativehumidity� and window insulation (RR value) when wind speed is �miles per hour (MPH)� Use thisinformation to estimate relativehumidity in your home in winter�

How moisturemovesWWaatteerr vvaappoorr moves primarily bytwo means:� DDiiffffuussiioonn — Water vapor tends

to move from areas of high con�centration to areas of low con�centration�Water vapor diffuses veryquickly in air� so the amount ofmoisture in various roomsquickly equalizes� However� ifthe temperature varies fromroom to room� relative humiditymay also vary in each room�

�� AAiirr mmoovveemmeenntt — As air movesthrough and about your home�it carries water vapor with it� Airmoves due to two naturalforces:a� TThhee ssttaacckk eeffffeecctt — Warm air

rises� as it is lighter than coolair� A familiar example of thestack effect is heat rising upa chimney�

■ ■ ■

To replace warm air rising upand out of your home� coolair is drawn in at the basethrough ground floor cracksunder doors and aroundwindows�

b� WWiinndd pprreessssuurree — As thewind blows against yourhouse� it forces air inthrough cracks on thewindward side� This pressurecauses air to escape from theopposite side of the house�

During the heating season� airmovement brings cool outside airinto your home� Even though thisoutside air may have a high relativehumidity� it contains only smallamounts of moisture because it isso cold�

WW ii nn tt ee rr HH oo mm ee MM oo ii ss tt uu rr ee PP rr oo bb ll ee mm ss

���

��

��

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��

��

�

�

��

�

Ind

oo

r re

lati

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mid

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(�

)

Indoor air temperature ��˚F

Outside temperature (˚F)

Quadruple glazing R��

�� MPH wind

Double glazing R�

Single glazing R��

Triple glazing R�

�� � � �� � �� � � �� ��

SSoouurrccee:: Hellevang� Kenneth J�� Keep Your Home Healthy AE����� North Dakota State University Extension Service� June ����: http://www�homemoisture�org/kyhh/ae�����htm

FFiigguurree ��:: Condensation on windows

After the cold air enters your home�its temperature increases and itsrelative humidity decreases� Oncethe air is warmed� it picks up watervapor generated by householdactivity� The warm moist air thenrises and exits through thechimney� cracks around windows�and other openings in the walls andceilings of your home�Water vapor from warm airescaping around upper storywindows condenses on coldwindows� This is why you often seefrost on the inside of second storywindows� while the first storywindows remain clear�Older construction techniquesallow the stack effect and windpressure to exhaust warm� moist airand to introduce large amounts ofcold outside air into homes� This iswhy indoor humidity levels in olderhomes are so low in winter andhumidifiers are often needed�

Side effects ofweatherizingThe same air movement thatremoves moisture also removesheat� Energy conservation practicessuch as caulking and weatherstrip�ping are aimed at trapping heatedair indoors and reducing the infil�tration of cold outside air�As a side effect of weatherizing�sometimes moisture is also trappedindoors� And too little outside air isintroduced to reduce humiditylevels (see figure �)�However� the solution to excesshumidity is not to go back to looseconstruction that allows air to movefreely in and out of the home� Thosehomes are at the mercy of outsideweather conditions�The forces that move air throughthe house are most active whentemperatures outside are coldestand winds are strongest� So looselyconstructed homes are likely to beover�ventilated on the coldest days�resulting in drafty� dry homes�

■ ■ ■

Figure � shows how the solution toone problem — sealing and insulat�ing to keep out cold air and preventwasteful heat loss — can some�times cause another — excessindoor humidity�

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M A I N T A I N I N G Y O U R H O M E

BBeeffoorree vveennttiillaattiioonn——■ high infiltration■ low humidity

AAfftteerr vveennttiillaattiioonn——■ low infiltration■ high humidity

FFiigguurree ��:: Weatherizing may increase humidity�

Solving winter moistureproblemsSolve water problems firstTThhee ffiirrsstt sstteepp iiss ttoo ffiinndd aanndd ffiixx lleeaakkssaanndd wwaatteerr ddaammaaggee�� Check undersinks and around tubs and showersfor drips� damp areas or dark stains�Check the walls and ceilings inadjacent rooms as well� Theproblem may show up as waterstains on the wall or ceiling thatbacks up to the leak�CChheecckk tthhee rrooooff ffoorr lleeaakkss�� Icicleshanging from the eaves mayindicate ice dams� IIccee ddaammss formwhen snow piles high on the roofand the weather stays cold� Snowtouching the roof melts� runs downthe roof under the snow to theeaves� and refreezes� Water mayback up behind the dam and leakinto the attic or sidewalls of thehome� causing damage (see “Firstaid for ice dams”)�

■ ■ ■

As figure � shows� icicles on theeaves may signal ice dams on theroof� Prevent ice dams to keepmelting snow from leaking into theattic�

CChheecckk bbaasseemmeenntt wwaallllss aanndd fflloooorrss��Stains on basement walls meanwater has soaked through andevaporated� Tape a piece of clearplastic tightly to the wall or floor� If water collects behind the plasticafter �� hours� moisture is seepingthrough� If the moisture is on theroom side of the plastic� condensa�tion is a problem�Basements often leak because poorsurface drainage allows heavy rainor rapidly melting snow to poolnext to the foundation�As much as ��� gallons (�� pints)per day can migrate throughporous basement floors and wallsfrom wet soil outside� CCoorrrreecctt iimmpprrooppeerr ssuurrffaaccee ddrraaiinnaaggee��Check the grading around your home�The ground surface should slopenoticeably away from the foundationat all points� If you have gutters anddownspouts� make sure they functionproperly and direct water well awayfrom the foundation�SSeeaall bbaasseemmeenntt wwaallllss aanndd fflloooorrss��If your grading and gutters keepwater away and moisture seepageseems slight� commercial damp�proofing compounds may solve theproblem� These are applied likepaint to inside walls�If water problems are severe�contact a reputable contractor�

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First aid for ice damsCClleeaarr ssnnooww ffrroomm tthhee rrooooff aa ffeewwffeeeett bbaacckk ffrroomm tthhee eeaavveess wwiitthh aalloonngg��hhaannddlleedd rrooooff rraakkee�� This rakeis designed so you can safelyremove snow from the ground� If you cannot reach the rooffrom the ground with this rake�consider hiring a roofing contractor�

PPrreevveenntt iiccee ddaammss —— KKeeeepp tthhee aattttiicc ccoooollSSeeaall ggaappss wwhheerree wwaarrmm aaiirr lleeaakkssiinnttoo tthhee aattttiicc�� Non�expandingfoam in a can will plug mostleaks� If air leaks around some�thing hot like a stovepipe� form agasket with sheet metal or usefiberglass insulation that will notburn or melt�AAdddd iinnssuullaattiioonn�� In cold climates�the attic should have an iinnssuullaatt��iinngg vvaalluuee ooff RR���� oorr mmoorree —— aattlleeaasstt ffoooott ooff iinnssuullaattiioonn oonn tthheeaattttiicc fflloooorr��VVeennttiillaattee tthhee aattttiicc�� In olderhomes� attics should have square foot vent opening forevery �� square feet of floor�divided equally between the topand bottom of the roof� Cold airflows in through vents in theeaves� pushing warm air up andout vents near the ridge�

iinnssuullaattiioonn

ssnnooww

iiccee ddaamm

mmeellttiinngg wwaatteerr

FFiigguurree ��:: Ice dam

RReedduuccee mmooiissttuurree ffrroomm ccrraawwll ssppaacceess��If your home is built over a crawlspace� reduce moisture from thissource by covering the crawl spacewith a moisture�resistant materialsuch as mil polyethelene plastic�Roll the material several inches upthe edge of the foundation� If youneed more than one sheet� be sureto overlap them� Use stones� bricksor dirt to keep this moisture barrierin place�

■ ■ ■

Figure �: If you have a crawl spacewith an earth floor� line the floorwith thick plastic to prevent evapo�ration�

Reduce moistureproduced indoorsAnother way to reduce relativehumidity is to decrease the amountof water vapor generated in thehome� As figure shows� consider�able water vapor is produced in thecourse of daily living� For example�a family of four will generate agallon and a half (� pints) of watervapor a day — just by breathing�Here are some ways to reduce theamount of water vapor produced inthe home:■ BBee ssuurree tthhee ccllootthheess ddrryyeerr vveennttss

oouuttddoooorrss�� A clothes dryer ventedindoors produces more than halfa gallon (� pints) of moistureper load�

■ KKeeeepp sshhoowweerrss aanndd bbaatthhss sshhoorrtt��■ CCoovveerr ppoottss aanndd ppaannss wwhheenn

ccooookkiinngg�� This reduces both evap�oration and cooking time�

■ AAvvooiidd ssttoorriinngg ffiirreewwoooodd iinnddoooorrss��

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M A I N T A I N I N G Y O U R H O M E

ggrroouunndd

jjooiisstt

iinnssuullaattiioonn

vvaappoorr bbaarrrriieerr

FFiigguurree ��:: Cover crawl spaces�

CCooookkiinngg aanndd ddiisshhwwaasshhiinngg ppiinntt ppeerr mmeeaall

SShhoowweerr—— ppiinnttppeerr �� mmiinnuutteess

BBrreeaatthhiinngg �� ppiinnttss ppeerr ddaayy ppeerr ppeerrssoonn

HHoouussee ppllaannttssuupp ttoo ppiinntt ppeerr ddaayy

FFiigguurree : Moisture sources in the home—approximate amounts of water vapor produced perday by selected indoor sources�

Increase ventilationProblems with excess moistureduring winter have become moresevere in cold climates since houseshave been tightened up to reduceheat loss� Reducing the amount ofmoisture generated in the homehelps� but often ventilation must beincreased as well�Unlike the traditional home inwhich natural forces determineventilation rates� the new approachallows occupants to determine ven�tilation rates�When you first start using ventila�tion to reduce cold weather con�densation problems� you may notget immediate results� This isbecause moisture is stored in yourhome’s wood and trim duringsummer when warm air holds morewater vapor� then released as tem�peratures cool� A house willproduce to pints of moistureper day — up to � gallons — asindoor materials dry during fall�So condensation can be a particularproblem at the beginning of theheating season� The relativehumidity of indoor air will droponly after moisture levels in thestructure have dropped�In winter� ventilation is the mosteffective and least expensive wayto reduce relative humidity� Insummer� remove moisture with adehumidifier or air conditioner�NNoottee:: Avoid using dehumidifiers inwinter� Dehumidifiers work best athigher temperatures and athumidity levels above �� percent�

Exhaust fan ventilationThe easiest option for increasingventilation is to use existingexhaust fans� A true eexxhhaauusstt ffaann isinstalled in a wall or ductedthrough the roof or an exteriorwall� and draws air out of thehouse�Be aware that ductless kitchen andbath fans do not exhaust air� butsimply filter and recirculate air�Bathroom fans with infrared heatlamps only help circulate air�To remove moisture effectively� runexhaust fans for �� minutes aftershowers� and �� minutes aftercooking and dishwashing�If this is inconvenient or inade�quate� consider installing a ddeehhuu��mmiiddiissttaatt ccoonnttrrooll to operate yourexhaust fan� You can set the fan toswitch on whenever moistureexceeds a certain level�Open a window slightly on theopposite side of the house toreplace vented air with cold� dryoutside air� Improved ventilationwill more than offset the heat youlose by opening the window whenthe fan is running�IIff yyoouu nneeeedd ttoo iinnssttaallll aann eexxhhaauussttffaann�� look for one with:■ A tight�fitting exterior damper�■ Eight air changes per hour for a

bathroom fan�■ Twelve to � air changes per

hour for a kitchen fan�■ Very low noise level so family

members will use it�

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WW ii nn tt ee rr HH oo mm ee MM oo ii ss tt uu rr ee PP rr oo bb ll ee mm ss

Run exhaust fans

after showers and

meals to remove

moist air�

Whole house ventilationFor new well�constructed homes�whole house ventilation systemsmay be the answer� The type bestsuited for cold climates exhausts airfrom kitchens and bathrooms� andsupplies fresh air to bedrooms�A common type is a hheeaatt rreeccoovveerryyvveennttiillaattoorr� These balance exhaustedair with incoming air� and transferheat from the outgoing air streamto the incoming air stream� Thesesystems are powered by quiet� low�volume fans that do not producedrafts�

Warm up coldsurfacesWarm up cold surfaces to a tempera�ture above the dew point for indoortemperature�humidity conditions� In many cases� high relativehumidity levels are not the cause ofmoisture problems� In homes wherethe relative humidity is in theacceptable �� to �� percent range

for winter� moisture problems canoccur because surface temperaturesdrop below the dew point for airwith that amount of water vapor�Single pane windows offer a con�venient example� A single layer ofglass has very little insulatingvalue� So the inside surface temper�ature of the glass will be close tothe outdoor temperature�A review of figure � reveals thatroom air at ��° F with a moderate�� percent relative humidity couldstill produce condensation on thesurface of single�glazed windowswhen the outside temperaturedrops below ��° F� This is becausethe inside surface temperature ofthe glass would be ��° F� or roughly�° F below the dew point�By adding another layer of glazing�you would raise the surface tem�perature above the dew point of��° F and prevent condensation�When your relative humidity levelsare higher or outside temperaturesare lower� the second layer ofglazing might not be enough� Forexample� if the outside temperaturedrops to �° F� condensation can beexpected on double�glazedwindows if the relative humidityremains at �� percent�A third layer of glazing will stopcondensation in most situations�Double�glazed windows with a lloowwee ((llooww eemmiittttaannccee)) ccooaattiinngg may alsobe effective�You could also add a tight�fittinginterior storm window or layer ofplastic� Kits containing clear plasticand double�stick tape are availablefor this purpose�

■ ■ ■

Figure �: Warm up cold surfacesand exhaust moist air from yourhome to prevent condensation inwinter�

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M A I N T A I N I N G Y O U R H O M E

FFiigguurree ��: Prevent condensation in winter�

RRaaiissee tthhee tteemmppeerraattuurree�� CCiirrccuullaattee wwaarrmm aaiirr��

IInnssuullaattee�� VVeennttiillaattee��

9

WW ii nn tt ee rr HH oo mm ee MM oo ii ss tt uu rr ee PP rr oo bb ll ee mm ss

Trouble spotsCovering windows with loose�fitting drapes can make condensa�tion problems worse� This blocks aircirculation and lowers the windowpane temperature� Yet moisturestill diffuses to the area behind thedrapes and condenses on coldwindows�This is similar to problems thatsometimes occur behind furnitureplaced against outside walls� or inclosets against exterior walls�Moisture may condense on thesewalls because heated room air doesnot circulate there to warm them�yet they are open enough to letmoist air through� When moisturecondenses on these walls� mold cangrow there�

Circulate warm airThe simplest short�term solution isto improve air circulation to coldsurfaces�Make sure warm air reachesproblem areas:■ Open drapes to warm up

windows�■ Leave closet doors open� and

make sure warm air circulates tothe back�

■ Move furniture away fromoutside walls�

■ Raise the temperature inproblem rooms�

Improve insulationThe ideal long�term solution is toimprove insulation for the surfaceswhere moisture condenses inwinter�Another trouble spot in somehomes is the corner betweenoutside walls and ceilings� Atticinsulation often is thin at this pointbecause either there is not enoughspace between the ceiling and theroof deck to accommodate the fullamount of insulation� or structuralmaterials displace insulation�Wind through attic vents may blowinsulation away from this area�Wall insulation may settle; and aircirculation to this area of the roomis limited (see figure )�In most cases� reducing indoorhumidity levels will cure theseproblems� Where this solution isnot effective� you will need towarm up cold surfaces�

■ ■ ■

Figure shows why you may needto insulate corners between outsidewalls and ceilings to preventmoisture problems that oftendevelop there�

iinnddoooorr aaiirr ffllooww

aaiirr ffllooww

■ Ventilation may move insulation�

■ Space for insulation overoutside edge of room maybe inadequate�

■ Extra structural materialsmay displace insulation�

■ Indoor air does not circulateto outside corners�

FFiigguurree :: Insulate corners�

Remove moldand mildewDrying up indoor air and fixingleaks are the best long�term treat�ments of mold problems� But if youfind small areas of mold onsurfaces� you can use the followingprocedure to remove it�Scrub the area with a dilute bleachsolution: cup of � percent house�hold bleach (sodium hypochlorite)in gallon of water�Wash surfaces with this bleachsolution and let dry� Rinse carefullyto remove dead mold material�Even dead mold spores can causeallergic reactions�Bleach is a strong chemical� Followthe directions on the containercarefully� Wear rubber gloves andavoid skin contact� Open windowsand run fans to ensure adequateventilation�CCaauuttiioonn::If you have extensive moldproblems� removing them can posehealth risks� Contact your localhealth department for help locatinga mold removal contractor� or youruniversity extension office for moldremoval guidelines�

Checklist forpreventing problemsAArree wwaatteerr lleeaakkss ccaauussiinngg tthheepprroobblleemm??■ Check that gutters are clear of

leaves and other material�■ Make sure downspouts carry

water away from the founda�tion�

■ Check to be sure the groundslopes away from the foundation�

■ If icicles form on the eaves� clearsnow from the roof� Check theattic for proper insulation andventilation�

■ Check roofing and flashing to besure it is in sound condition�

■ Check that basement walls andfloors are dry�

DDooeess ffoogg oorr ffrroosstt ppeerrssiisstt oonn ddoouubbllee��ggllaazzeedd wwiinnddoowwss wwhheenn oouuttssiiddee tteemm��ppeerraattuurreess aarree aabboovvee ��°° FF??■ Open drapes and shades to

allow heated air to reachwindows�

■ Keep showers short� ■ Use exhaust fans after bathing

and cooking�■ Make sure the clothes dryer is

vented outdoors�■ Minimize indoor storage of

firewood�■ Consider reducing the number

of house plants�IIss mmooiissttuurree ccoonnddeennssiinngg oonn wwaallllss��bbuutt nnoott oonn wwiinnddoowwss??■ Increase air circulation to

problem areas�■ Improve insulation of exterior

walls and corners near problemareas�

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M A I N T A I N I N G Y O U R H O M E

ConclusionMoisture problems can be difficult tosolve� The solution may often involveseveral steps� or you may need tochoose among several solutions�This publication provides you withbasic information on moistureproblems to help you make effec�tive choices and develop your ownsolutions� We hope you will use this informa�tion to think of winter moistureproblems in terms of their causes�and that this approach will saveyou time� trouble and money�

ReferencesAngell� William� Moisture Sources

Associated with Potential Damage inCold Climate Housing� Cold ClimateHousing Information Center�University of Minnesota� �:http://www�extension�umn�edu/abstracts/nonweb/abstract�html?item������

Hellevang� Kenneth J�� Keep Your HomeHealthy AE����� North DakotaState University Extension Service�June ����: http://www�homemoisture�org/kyhh/ae�����htm

Merrill� John L�� and Kim Terry�HomeWise:Help for NewHomeowners B� � University ofWisconsin�Extension CooperativeExtension Publishing� �����

Merrill� John L�� and Kim Terry et al�HomeWorks News B���� Universityof Wisconsin�Extension CooperativeExtension Publishing� ����

Merrill� John L�� Maintaining YourHome:Controlling Molds and MildewB�� � University of Wisconsin�Extension Cooperative ExtensionPublishing� ����� See Home &Family Home Care:cecommerce�uwex�edu

Roberson� Judy A�� Richard E� Brown�Jonathan G� Koomey and Steven E�Greenberg� RecommendedVentilation Strategies for Energy�Efficient Production Homes�Lawrence Berkeley NationalLaboratory� ��:http://enduse�lbl�gov/projects/ESVentilation

YYoouurr ccoouunnttyy oorr aarreeaa uunniivveerrssiittyyeexxtteennssiioonn ooffffiiccee offers programsand publications on maintainingyour home� Look online or in thephone book under county govern�ment�WWeebb ssiitteess — If you do not have acomputer� try your local library�Most libraries have a free computerconnected with the Internet�

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M A I N T A I N I N G Y O U R H O M E

©© �������� by the Board of Regents of the University of Wisconsin System� Send inquiries about copyright permissions toCooperative Extension Publishing Operations� �� Extension Bldg�� ��� North Lake Street� Madison� WI ���� AAuutthhoorr:: John L� Merrill� professor� Department of Environment� Textiles and Design� University of Wisconsin�Madison� andhousing specialist� UW�Extension�AAcckknnoowwlleeddggmmeennttss:: Figure � reprinted by permission of North Dakota State University Extension Service� Figures � and by Hawley Wright� Other figures by John Merrill�PPrroodduucceedd bbyy CCooooppeerraattiivvee EExxtteennssiioonn PPuubblliisshhiinngg OOppeerraattiioonnssUUnniivveerrssiittyy ooff WWiissccoonnssiinn��EExxtteennssiioonn�� U�S� Department of Agriculture and Wisconsin counties cooperating� UW�Extensionprovides equal opportunities in employment and programming� including Title IX and ADA� If you need this material inanother format� contact the Office of Equal Opportunity and Diversity Programs or call Cooperative Extension PublishingOperations at �/� ��� ���Copies of this publication are available from Wisconsin county UW�Extension offices or from Cooperative ExtensionPublications: (��) �������; Fax (��) ������; cecommerce�uwex�edu

MMaaiinnttaaiinniinngg YYoouurr HHoommee:: WWiinntteerr HHoommee MMooiissttuurree PPrroobblleemmss ((BB������)) R��������

NNoottee:: This publication replaces Moisture Problems in the Home (NCR��)�