Smart fixes for frost-dam­aged clos­ets

Winnipeg Free Press - Section G - - FRONT PAGE -

QAt the bot­tom of two clos­ets in our 1954 bun­ga­low there is frost and dam­age to the plas­ter walls. Can you please sug­gest an in­ex­pen­sive way to solve this prob­lem? Thank you. Lawrie Marmel An­swer: There are a cou­ple of sim­ple things you can do to pre­vent frost buildup inside the clos­ets in your home. One of th­ese should help ad­dress the prob­lem of min­i­mal in­su­la­tion in older homes like yours and the other will help solve a cou­ple of ha­bit­ual prob­lems caused by home­own­ers.

Be­fore you tackle the is­sue of frost and dam­age oc­cur­ring inside the clos­ets in your home, you should know the causes. Hav­ing this knowl­edge will not only help solve the prob­lem, but it should pre­vent a re­cur­rence, should you for­get this ad­vice in the fu­ture. There may be sev­eral con­tribut­ing fac­tors to the ap­pear­ance of frost in your clos­ets.

Ini­tially, I will as­sume the frost is only ap­pear­ing in clos­ets that have one or more walls which is an ex­te­rior wall of the home. The rea­son this is likely is th­ese walls may have min­i­mal or no in­su­la­tion in some ar­eas, which can al­low them to be much colder than sur­round­ing ar­eas. Heat can be lost by ther­mal bridg­ing of the ma­te­rial that makes up the con­struc­tion of the wall to the cold air out­side the home. With lit­tle in­su­la­tion to pre­vent heat re­ten­tion, this is almost a cer­tainty. Even if the wall has some ther­mal in­su­la­tion be­tween the studs, there may be noth­ing in the cor­ner in the ex­te­rior wall. Also, it is quite common for small gaps to ap­pear un­der the bot­tom plate of th­ese stud walls, due to nor­mal shrink­age or warp­ing of the wood over time. Both of th­ese ar­eas may al­low a sub­stan­tial amount of cold air to in­fil­trate this sec­tion of the build­ing en­ve­lope, cre­at­ing an ex­cel­lent lo­ca­tion for con­den­sa­tion.

The sec­ond re­quire­ment for frost buildup in this trou­ble­some area is mois­ture. Where does this mois­ture come from in a closet that is nowhere near a wa­ter source? The an­swer is the warm heated air inside the home. This heated air will con­tain a cer­tain amount of mois­ture, de­pend­ing on the rel­a­tive hu­mid­ity (RH), at any given time. In the mid­dle of win­ter, the air in the home may seem quite dry, but it ac­tu­ally con­tains much more mois­ture that the frigid air out­side the home. When this warm air hits a very cold sur­face, or drafty cold air from out­side, it will con­dense on the cold wall sur­face. If it is cool enough, this con­den­sa­tion will freeze, and then you have the con­di­tions for your frosty wall. Keep­ing the RH lower in the home may help pre­vent ex­ces­sive con­den­sa­tion, but keep­ing the closet walls from get­ting cold enough inside to freeze any con­den­sa­tion is the key to solv­ing your is­sue.

The first thing to ad­dress is the lack of in­su­la­tion or air seal­ing, typ­i­cal in homes of your age. If the back or side walls of the closet are in­deed ex­te­rior walls, it is almost cer­tain that there is no in­su­la­tion in be­tween the studs that make up the inside cor­ner of the closet. Be­cause of the con­fig­u­ra­tion of an inside cor­ner of a wood framed wall, there is of­ten a nat­u­ral void in the ex­te­rior wall at this lo­ca­tion. If both walls shar­ing the cor­ner are out­side walls, the prob­lem may be ex­ag­ger­ated. To fill this void after the fact, small holes may be drilled right in the cor­ner, an­gling to­ward the ex­te­rior wall. Care must be taken not to drill through any elec­tri­cal wires, or other ob­struc­tions, so do­ing a lit­tle ex­ploratory work ahead of time may be pru­dent. Once the holes are drilled, filling the void may be no harder than pump­ing in a few cans of ex­pand­ing polyurethane foam in­su­la­tion through th­ese small open­ings. Once the foam is cured, the ex­cess that oozed through the holes can be cut off with a util­ity knife and the walls re­paired with a patch­ing com­pound be­fore paint­ing.

This same method may also work if there is sub­stan­tial air leak­age un­der the bot­tom plate of the stud wall. This may only be iden­ti­fi­able by re­mov­ing the base­board or quar­ter round at the bot­tom of the wall. Once th­ese are re­moved, a flash­light or thin metal blade may be used to de­ter­mine if the gap in this lo­ca­tion is large enough to cause an is­sue. If the gap is larger than three to five mil­lime­tres, blow­ing in more foam to air seal this lo­ca­tion is war­ranted. Be­cause of the lo­ca­tion and size of this gap, low ex­pan­sion foam, de­signed for door and win­dow in­stal­la­tions, may be a bet­ter choice in this tight spot. If the space is smaller than a few mil­lime­tres, filling the gap with a good qual­ity ex­te­rior grade caulk­ing may be all that is needed to stop the cold air in­fil­tra­tion.

The last is­sue that will cause ex­ces­sive mois­ture, frost, or mould in clos­ets is a lack of air­flow along the walls. Be­cause most clos­ets have doors that pre­vent heated air from the warm air reg­is­ters eas­ily ac­cess­ing the inside walls, they can be sub­stan­tially colder than out­side the closet. This may be com­pounded by the common prac­tice of stor­ing large amounts of boxes, shoes, or cloth­ing on the floor of the closet. If this stor­age is touch­ing the ex­te­rior walls, it will fur­ther pre­vent warm air from cir­cu­lat­ing over the cold wall sur­faces. The stored cloth­ing can trap moist air that does en­ter the closet, en­sur­ing slow cool­ing and guar­an­tee­ing con­den­sa­tion. With limited warm air cir­cu­la­tion to dry the con­den­sa­tion, it may freeze, as the ex­te­rior closet walls fur­ther cool, at night.

The frost form­ing on the inside walls of your clos­ets is likely a com­bi­na­tion of a nor­mal de­fect in the con­struc­tion meth­ods used in your home, com­bined with some of your nat­u­ral habits. Filling the gaps inside the cor­ners and un­der the base­boards will min­i­mize the ef­fects of the con­struc­tion flaws, while elim­i­nat­ing ex­ces­sive stor­age and leav­ing the closet doors open will help pre­vent a small prob­lem for es­ca­lat­ing to the point of frost dam­age. Ari Marantz is the owner of Trained Eye Home In­spec­tion Ltd. and the past pres­i­dent of the Cana­dian As­so­ci­a­tion of Home & Prop­erty In­spec­tors — Man­i­toba ( Ques­tions can be emailed to the ad­dress be­low. Ari can be reached at 204-291-5358 or check out his web­site at trained­


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