Ventilation Fan Sources

I love your magazine and the tremendous information in each issue.

I live 100 miles from Richmond, Va., on the Chesapeake Bay. My company does a number of crawlspace renovations as well as new foundations. Can you recommend a supplier for the "continuous-duty low-sone fan" that you show in your article ("Sealing Crawlspaces in Flood Zones") on page 19 of the May/June 2006 issue? My HVAC sub has had no luck tracking one down.

Michael Harvey (via e-mail)

Editor's note: Several manufacturers offer quiet fans rated for continuous duty. Fantech ( makes a number of inline duct fans that would work, including the 122-cfm FR Series fan, featuring a lightweight plastic housing. These can be mounted in exterior or wet locations, allowing for some creative placement that can ensure absolute quiet. Panasonic's Whisper Line models ( are also excellent options.

Online sources for these models include Westside Electrical & Lighting ( and Energy Federation (

Detailing Crawlspaces

I read your article on sealing crawlspaces in flood zones (Soundings, May/June 2006) and found it to be very good, although you may want to consider adding another detail to the job:

Adding batt fiberglass insulation to the rim joist is one way to seal above the foundation. But fiberglass insulation is not an air barrier, and therefore does not effectively seal the crawlspace from heat loss and moisture infiltration. So before adding the batt insulation, I would recommend caulking or air-sealing the rim joist and sill plate with one-part foam. Then add 1-inch foil-faced rigid insulation over the batt, and seal around the rigid insulation. Although this may be time consuming, it will help prevent moisture infiltration and, better yet, prevent excessive heat loss from the conditioned area.

Another method you might want to consider would be to seal the sill and band joist with two-part foam. Although this may be a little more expensive, it would be faster and less labor intensive.

Rich Manning Energy Master & Environmental Solutions (via e-mail)

Mold Remediation

Good article on mold remediation ("Genuine Mold," May/June 2006). However, I did detect one item that goes against current wisdom. Post-remediation testing should be conducted by a third party, not by the mold remediation company.

Barbara L. Lee (via e-mail)

Illustration Correction

In the article "Low Country Rx: Wet Floodproofing" (July/August 2006), we overlooked inclusion of structural sheathing over the steel studs in one of the cavity-wall assemblies (Figure 3, page 40). The corrected illustration and original caption are shown at right.

Shown here are two options for drainable and dryable cavity-wall assemblies suggested by building scientist Joseph Lstiburek. The wall designs share several key characteristics: (1) No water-sensitive materials are used; (2) exterior cavities are vented to the exterior; (3) interior cavities can be opened to allow passive air-drying in the event of a flood by removing strips of wall material at top and bottom to encourage convective airflow.