Flood in a Passive House: Lessons Learned

This small but elegant home in Camden, Maine, was designed and built by Belfast, Maine, Passive House builder EcoCor in collaboration with the owners. The Passive House envelope was completed using EcoCor's trademark panelizing system, but the homeowners took over at the painting and trim stage.

The overnight plumbing break flooded the newly built Passive House with more than a foot of water, some of which was able to seep into the outer insulated cavity of EcoCor's double wall system. Here, a worker pulls damp insulation out of the outer wall from inside the house.

Here is a view of the wall during remediation work after the flood. Drywall has been removed to a point above the water damage line, Roxul insulation has been pulled out of the inboard wall stud cavity, and sections have been cut out of the OSB air barrier in each stud bay to allow access to the outer wood I-joist insulated bays. Note the red color of the fluid-applied air barrier coating applied to the inside of the OSB sheathing during construction.

Another look at the wall after demo during flood remediation work. Drywall and Roxul rock wool insulation have been removed, holes have been cut in the OSB air control layer, and damp insulation has been pulled out of the outside cavity of the double insulated wall system.

Another view of the exposed wall system during water damage remediation, the day after the flood occurred.

Open wall cavities under a window during flood damage restoration work. The double wall cavities had to be exposed and dried out using heaters and dehumidification equipment.

Once the wall cavities were dried, the crew applied patches over the OSB air barrier using pieces of ZIP sheathing. Here, a worker applies adhesive caulk sealant to the original OSB air barrier before fastening on the patch.

EcoCor carpenter Richard Perry screws a ZIP sheathing patch over the hole in the double wall air barrier layer after removing wet insulation and drying the wall assembly.

Here's a look at ZIP sheathing patches applied to repair holes in the OSB air control layer. The round holes in the center of the patches will allow fresh dry cellulose insulation to be dense-blown into the cavities.

Another step in the repair work: cellulose insulation has been dense-blown into the cavity through the hole in the center of the ZIP sheathing patch.

The cut-out circles made when the holes were drilled into the ZIP sheathing patches were replaced as plugs for the holes, then the disks were sealed using squares of Pro Clima Uni Tape (www.foursevenfive.com).

A Pro Clima self-adhesive membrane piece in place to seal the insulation hole in a ZIP System patch in the double wall.

Re-sealing the repaired OSB air barrier layer after removing and replacing wet cellulose insulation. After the repair, the house scored about 0.27 ACH50 on a repeat blower door test for Passive House certification.

EcoCor carpenter Richard Perry seals the joint between the fresh ZIP System patch and the existing OSB sheathing air barrier using Prosoco fluid-applied membrane (the same material used earlier to address air leakage through the face of the OSB).

A completed, air-sealed patch in the home's OSB sheathing air control layer after removal of wet insulation and installation of new cellulose.

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