Lots of rea­sons for at­tic and roof leaks

Winnipeg Free Press - Section F - - HOMES - ARI MARANTZ

QUES­TION: I have been in the roof­ing busi­ness for many years as an owner of Dr. Roof, and I have a con­cern where I would like your opin­ion.

With such an ex­tended pe­riod of ex­tremely cold tem­per­a­tures, com­bined with heavy snow loads, we are ex­pect­ing huge prob­lems with con­den­sa­tion and ice-dam leaks once the tem­per­a­tures rise above freez­ing. There have been lit­tle to no freeze/thaw cy­cles this year, which ap­pears to be caus­ing larger-than-nor­mal frost and ice buildup in at­tics and roof cav­i­ties. Once the warmer tem­per­a­tures hit, I ex­pect this ice and frost will melt, caus­ing what ap­pears to be roof leaks.

With all the home im­prove­ments people are do­ing, like in­stalling new high-ef­fi­ciency fur­naces and new win­dows, these prob­lems ap­pear to be get­ting more fre­quent ev­ery year. Some cus­tomers have up­graded heat­ing sys­tems, in­su­la­tion and win­dows af­ter we have re­placed their roof­ing, and they call ev­ery year com­plain­ing about roof leaks. There is noth­ing wrong with the roof­ing and we try to ex­plain that the mois­ture is com­ing from their at­tic, not the roof.

Do you agree that this is hap­pen­ing and do you think this spring will be worse than nor­mal due to the cold weather? Norm Gre­goire AN­SWER: Prob­lems with at­tic mois­ture and rel­a­tive hu­mid­ity (RH) is in­creas­ing in homes due to fur­nace up­grades and tight­en­ing of build­ing en­velopes, but whether that trans­lates into ac­tual leak­age can be ex­tremely un­pre­dictable.

For ex­am­ple, mois­ture is­sues of­ten oc­cur af­ter chim­neys are closed when a high-E fur­nace is in­stalled, es­pe­cially when win­dows are re­placed at the same time. But whether this be­comes a big­ger prob­lem than usual when this win­ter’s ex­tended cold streak fi­nally ends is yet to be seen.

I get nu­mer­ous calls ev­ery year about this prob­lem oc­cur­ring in homes with vaulted ceil­ings and knee-wall at­tics, where mois­ture buildup is ex­pected. But some years I also get in­quiries from many home­own­ers who are sud­denly faced with wa­ter leak­ing into walls, ceil­ings or win­dows even though they’ve never ex­pe­ri­enced this pre­vi­ously. Some­times it seems to be re­lated to en­ergy-ef­fi­ciency im­prove­ments, but other times it’s more of a mys­tery.

Sur­pris­ingly, some homes ap­pear to have more at­tic frost and mois­ture is­sues af­ter newer roof­ing is in­stalled, even when more vents are in­stalled. I can’t say ex­actly why this oc­curs, but it may be that the old, worn shin­gles al­lowed some mois­ture to es­cape, while the new ones are well sealed and trap this mois­ture in the wood and the at­tic.

This nor­mally causes lit­tle con­cern, other than a large amount of frost vis­i­ble when some­one looks into the at­tic, as long as at­tic ven­ti­la­tion is in­creased to com­pen­sate for the new roof­ing.

Some­times, the prob­lem can be linked to weather. I vividly re­mem­ber get­ting dozens of calls from fran­tic home­own­ers a few years ago about leak­age in late win­ter and early spring. There had been un­usu­ally warm and wet weather well into Novem­ber, fol­lowed by a sharp drop to sub-zero tem­per­a­tures for a sev­eral months.

My con­clu­sion was that this left many homes with un­usu­ally high amounts of mois­ture trapped in their at­tics which sud­denly froze and then melted quickly dur­ing the first thaw.

Even with the un­usu­ally large amounts of frost you and I are both see­ing in at­tics this win­ter, it may not lead to ma­jor leak­age if the weather grad­u­ally warms. As long as we don’t get a very sud­den thaw, with tem­per­a­tures ris­ing from the re­cent mi­nus-20s and mi­nus-30s to above zero overnight, many homes may be fine. At­tic frost should melt slowly, al­low­ing evap­o­ra­tion, if we get a grad­ual warmup over the next cou­ple of months.

But if we get a very sud­den thaw, look out!

The most ef­fec­tive mea­sures that home­own­ers can take to pre­vent ex­ces­sive mois­ture in­tru­sion this spring is to re­duce in­door RH and shovel their roofs.

Keep­ing in­door mois­ture lev­els low can of­ten be ac­com­plished by us­ing bath­room and kitchen ex­haust fans for a longer pe­riod of time, en­sur­ing dry­ers are prop­erly vented and run­ning fur­nace fans con­tin­u­ously.

Shov­el­ling the roof will re­duce the amount of raw ma­te­rial for ice dams and al­low the sun to warm the roof deck and slowly melt frost on the un­der­side of the roof sheath­ing.

But safety first. It may be best to leave this job to a prop­erly trained and in­sured roofer.

Ari Marantz is the owner of Trained Eye Home In­spec­tion Ltd. and the Pres­i­dent of the Cana­dian As­so­ci­a­tion of Home & Property In­spec­tors - Man­i­toba (www.cahpi.mb.ca). Ques­tions can be e-mailed to the ad­dress be­low. Ari can be reached at (204) 291-5358 or check out his web­site at www.trained­eye.ca.

The most ef­fec­tive mea­sures that home­own­ers can take to pre­vent ex­ces­sive mois­ture in­tru­sion this spring is to re­duce in­door RH and shovel their roofs.

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