Window well covers 101

Posted Mar 31, 2021 in Waterproofing, Window Wells and Covers

Nor­mal­ly, base­ment leaks are attrib­uted to foun­da­tion cracks and oth­er points of entry for water through foun­da­tion walls. To a less­er extent, wet base­ments result from poor win­dow well drainage; unfor­tu­nate­ly, when a base­ment leak is the result of a poor­ly drain­ing win­dow well, a sig­nif­i­cant amount of water can enter into a base­ment very rapidly.

Win­dow well cov­ers — the fix for over­flow­ing win­dow wells?

Typ­i­cal­ly, home­own­ers log­i­cal­ly con­clude that poor win­dow well drainage prob­lems can be over­come by pre­vent­ing water accu­mu­la­tion in a win­dow well. This is a log­i­cal con­clu­sion as the water that accu­mu­lates in a win­dow well orig­i­nates with rain and/​or melt­ing snow. Fur­ther­more, it is log­i­cal to con­clude that, since the top of a win­dow well is ful­ly exposed to the ele­ments, cov­er­ing a win­dow well is an effec­tive way to pre­vent water accumulation.

When it has been con­firmed that a win­dow well has filled with water that sub­se­quent­ly leaked into their base­ment, peo­ple tend to run to the local hard­ware store to buy clear plas­tic win­dow well covers.

Win­dow well design and drainage

While the pre­ven­tion of win­dow well drainage prob­lems appears sim­ple at a first glance, the real­i­ty is a bit more complicated.

When ini­tial­ly installed, win­dow wells are filled with clear grav­el that has excel­lent drainage qual­i­ties, and typ­i­cal­ly include a drain to the weep­ing tile. Giv­en the inher­ent design char­ac­ter­is­tics of win­dow wells ensur­ing effi­cient water drainage, a log­i­cal ques­tion is: why does a win­dow well over­flow and fail to drain? The answer to this ques­tion is quite sim­ple: because the grav­el and/​or drain are either clogged or obstructed.

A com­mon cause of win­dow well drainage prob­lems is an obstruct­ed grav­el lay­er. Leaves, news­pa­per, and plas­tic bags often end up in a win­dow well, effec­tive­ly pre­vent­ing water from drain­ing into the grav­el; this is anal­o­gous to a kitchen sink with food obstruct­ing the drain. Clear­ly, it is essen­tial to ensure that win­dow wells remain clear of debris; there­fore, reg­u­lar clean­ing is required. Plas­tic win­dow well cov­ers are very effec­tive at keep­ing debris out of win­dow wells.

Here is an exam­ple of a cus­tom win­dow well cov­er that is installed to pre­vent debris from accu­mu­lat­ing in a win­dow well.

Window Well Covers Custom Made

The effec­tive­ness of win­dow well cov­ers in pre­vent­ing win­dow well drainage problems

A debris-filled win­dow well is not the pri­ma­ry rea­son that win­dow wells fail to drain ade­quate­ly. Fur­ther­more, the major­i­ty of the water that enters a win­dow well does not enter from the uncov­ered top. These two facts are very sig­nif­i­cant when eval­u­at­ing the effec­tive­ness of win­dow well cov­ers for the pre­ven­tion of win­dow well drainage problems.

With respect to exces­sive rain­wa­ter enter­ing a win­dow well from the top, one must con­sid­er the sur­face area of a win­dow well, as well as the amount of rain­fall and the drainage effi­cien­cy of the win­dow well. The aver­age gal­va­nized win­dow well is 36” wide with a 12” pro­jec­tion; con­se­quent­ly, the area into which rain can enter the win­dow well is 3 ft² which is a rel­a­tive­ly small area. Giv­en that the vol­ume of water that such a win­dow well can hold approach­es 40 gal­lons, and that the win­dow well does drain, a con­sid­er­able amount of rain would have to fall direct­ly into the win­dow well for it to fill up and cause a base­ment leak. This does hap­pen how­ev­er when an eave­strough dumps water direct­ly into a win­dow well.

If rain­wa­ter enter­ing a win­dow well via the top is not the cause of win­dow well drainage prob­lems, then installing a win­dow well cov­er is of lit­tle val­ue. While the pres­ence of debris such as news­pa­per and plas­tic bags in a win­dow well can com­plete­ly pre­vent a win­dow well from drain­ing, the most com­mon prob­lem encoun­tered is soil con­t­a­m­i­na­tion of the grav­el lay­er and/​or the asso­ci­at­ed drain.

Clogged window well drain

Soil enters a win­dow well in three ways

  1. Over the top of the win­dow well (typ­i­cal­ly due to exces­sive­ly high grad­ing rel­a­tive to the height of the win­dow well);
  2. Between the foun­da­tion wall and the win­dow well affixed to it (the win­dow well must be fas­tened tight­ly to the wall); and
  3. From beneath the win­dow well (the height of the win­dow well being insuf­fi­cient for the depth of the base­ment window).

When soil enters a win­dow well, the soil mix­es with the clear grav­el cre­at­ing a mud­dy grav­el lay­er with an asso­ci­at­ed loss of drainage effi­cien­cy. In extreme cas­es, the soil will con­t­a­m­i­nate the drain as well. Soil con­t­a­m­i­na­tion of the grav­el lay­er and win­dow well drain can­not be pre­vent­ed by installing a win­dow well cover.

What our customers say

  • We con­tract­ed Fam­i­ly Water­proof­ing Solu­tions for exte­ri­or wall seal­ing and foun­da­tion crack repair ser­vices. Ken was very thor­ough in explain­ing the work that would be done, and his crew did a great job. This busi­ness was a plea­sure to work with.

    Stacie T.
  • Work­man­ship and ser­vice were excel­lent. Would rec­om­mend with­out reservation.

  • You and your crew did a great job in our base­ment and crawl­space. You went the extra mile to insure that all of our water seep­age prob­lems are over. We would rec­om­mend you high­ly to oth­er peo­ple. Your qual­i­ty and time­ly work out­match­es all the others.