Crawlspace encapsulation facts

Posted Mar 31, 2021 in Waterproofing, Crawlspace Encapsulation

Crawlspace after

Although not part of the liv­ing or occu­pied area, a crawl­space is one of the more impor­tant areas of a build­ing, yet one of the most neglect­ed and mis­un­der­stood areas. Actu­al­ly, it has a pro­found impact on the air qual­i­ty in the occu­pied area of the build­ing because of the stack effect. As air warms with­in the build­ing enve­lope, it moves upward; that is the stack effect. The air with­in a crawl­space trav­els upward, infil­trat­ing the liv­ing area through the duct­work, gaps in the floor­ing, through and around holes from wiring, con­duit, and plumb­ing. If there are indoor air qual­i­ty issues in the crawl­space, they will impact the liv­ing areas on the floor above. Up to 40% of the air on the first floor in a home orig­i­nates from the crawl space or basement.

Crawl­space encap­su­la­tion is a term refer­ring to the process of elim­i­nat­ing unhealthy con­di­tions by seal­ing and insu­lat­ing the entire crawl­space for improved ener­gy effi­cien­cy and indoor air qual­i­ty through­out the home. Oth­er terms some­times used to describe the crawl­space encap­su­la­tion are closed crawl­space, sealed crawl­space, and con­di­tioned crawlspaces.

The method entire­ly iso­lates the crawl space from the ground and out­side air by lin­ing the foun­da­tion walls and crawl­space floor with an extra-heavy rein­forced vapor bar­ri­er and maybe installing either a con­di­tion­ing sys­tem or a dehu­mid­i­fi­er. By seal­ing the crawl­space with a com­bi­na­tion of poly wrap and insu­la­tion, air infil­tra­tion and mois­ture infil­tra­tion are reduced, ensur­ing a health­i­er and safer home with less risk of mold and reduced ener­gy bills.

The rea­son the vent­ed crawl spaces have high­er humid­i­ty is actu­al­ly pret­ty sim­ple. Warmer air can hold more mois­ture, so in the sum­mer­time, the out­door air can bring a lot of extra water vapor with it when it comes into a crawl space through the vents. When that warm, humid air comes into the crawl­space and cools off, the rel­a­tive humid­i­ty can go even higher.

The process of crawl­space encap­su­la­tion begins by sur­vey­ing the house with ener­gy diag­nos­tic tools, includ­ing an infrared ther­mal imag­ing cam­era and a blow­er door to iden­ti­fy rates of air leak­age and areas where insu­la­tion is miss­ing or com­pro­mised, and where cracks and gaps in the build­ing enve­lope are lead­ing to air leak­age. The next step is to address these areas using air seal­ing mate­ri­als which may include a com­bi­na­tion of insu­la­tion, caulk, weath­er-strip­ping, poly wrap, spray foam, and any oth­er appro­pri­ate mate­ri­als. At the end of the project, your crawl­space is brought inside the build­ing enve­lope, which leads to a vari­ety of ben­e­fits such as:

1. A more com­fort­able home-

In sum­mer the house won’t be mug­gy; dur­ing win­ter floors won’t be cold.

2. Breathe easier-

High­ly improves indoor air quality.

3. Reduce the chances of cost­ly floor repairs-

Mois­ture rots wood and caus­es hard­wood floors to buckle.

4. No more critters-

A damp and humid crawl space is just invit­ing for any bug, such as termites.

5. An encap­su­lat­ed crawl space is an attrac­tive sell­ing feature-

Poten­tial buy­ers com­par­ing two sim­i­lar hous­es will find the one with an encap­su­lat­ed crawl space more appealing.

6. Reduced mois­ture problems-

Water and mois­ture are equal­ly dev­as­tat­ing to your home. Water keeps a mois­ture prob­lem alive as well as deliv­er­ing a pun­ish­ing blow to your foun­da­tion. Even if you get a stand­ing water prob­lem under con­trol you may not be done with the mois­ture prob­lem. When the tem­per­a­ture of the air is warmer than the tem­per­a­ture of the sur­faces in your crawl space you have con­den­sa­tion, which means trou­ble for your home.

7. Reduced risk of mold, mildew and fun­gus problems-

Dry Rot is a fun­gus and so is Mold and Mildew. All three are liv­ing plants and need food, water, and car­bon diox­ide, among oth­er things, to live. The food fun­gus eat is our house. So its food source can’t be removed, either the car­bon diox­ide. There­fore, to pre­vent the fun­gus tem­per­a­ture and mois­ture must be controlled.

8. Reduced cool­ing costs-

Water runs out of your air con­di­tion­er when it is run­ning; this is a byprod­uct of cool­ing the air before it goes into your home. The cool­ing coils that cool the air also cause con­den­sa­tion by draw­ing the mois­ture out of the air. The warm mois­ture in the air, when it comes in con­tact with the cold coils, warms the cool­ing coils mak­ing your air con­di­tion­er work hard­er to keep the coils cold. This prob­lem with the mois­ture will make your air con­di­tion­er run longer. The more mois­ture, the hard­er it has to work. The hard­er your air con­di­tion­er has to work the more expen­sive it is to cool your home. Elim­i­nate the mois­ture, elim­i­nate this cycle.

9. Reduced ener­gy bills:

Crawl space encap­su­la­tion can reduce ener­gy bills by up to 20%.

10. Make your heat­ing & cool­ing equip­ment and ducts last longer:

An air han­dler and ducts in a vent­ed crawl­space will not last as long as equip­ment in a con­di­tioned crawlspace.

11. Qual­i­fy for rebates and tax incentives:

Some util­i­ties offer rebates. The fed­er­al gov­ern­ment has tax incen­tives for home per­for­mance improve­ments. Some state and local gov­ern­ments offer incen­tives as well.


Crawl­space encap­su­la­tion is becom­ing a very pop­u­lar home improve­ment. The crawl­space is no longer neglect­ed and instead is treat­ed as a part of the home like a base­ment. By trans­form­ing your crawl­space into an encap­su­lat­ed crawl­space you are cre­at­ing a space you can con­trol. The goal is to com­plete­ly elim­i­nate out­side air and ground mois­ture from enter­ing the build­ing enve­lope. The list of ben­e­fits, as you see, goes far beyond just sav­ing on the ener­gy bills and clean­er air.

Look­ing to learn more about the ben­e­fits of crawl­space encap­su­la­tion for your home, or have a water­proof­ing relat­ed issue? Let Fam­i­ly Water­proof­ing Solu­tions take care of your crawl­space encap­su­la­tion and all of your water­proof­ing needs. Call us today (708) 330‑4466 and sched­ule an appoint­ment.

What our customers say

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

  • 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.
  • 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.