Archive for the ‘Ventilation’ Category

I frequently recommend at least a quality pleated air filter over the cheapie blue or green see through type as shown below.

MERV ratings range from 1 – 16 and measurements are in microns. Some of the common particles related to MERV ratings are pet dander, insecticide dust, smog, dust, viruses, wood, tobacco smoke, spores, bacteria and pollen.
Some of the most common filters found in residential use only have a merv rating of 1 to 4. I call these “bird stoppers” These are typically disposable panel type filters and do not do a good job of filtering the air because they will not stop particles smaller than 10 microns.

There are some manufacturers that have specific recommendations for their equipment, which should be followed for warranty purposes.



At a Home Inspection the other day I saw the worst case of mold in a crawlspace in 11 years of inspecting in Pensacola and Gulf Shores areas. This mold substance is so embedded into the floor and joists under the home I could put my hand right through the framing members.

Should have ventilated

Should have ventilated



I sure am glad I wear a respirator mask

There is lots of controversy regarding the ventilation or the lack of ventilation in crawlspaces under homes. Locally here in Pensacola, FL and Gulf Shores, AL  I have seen only a few crawlspaces that are not vented. Of those few homes I saw which are not vented, they were not updated with a completely sealed structure nor an HVAC system installed. The result was no mold (yet).

The pictures are from a crawlspace I inspected yesterday, which is typical for me to see this type of mold / fungus.

Building code says put a vapor barrier down on the ground and add some vents. It is very rare not to see some mold growing somewhere under these homes. I would like to see some sort of retro fit kit that is easy, quick and relatively inexpensive that would close in and condition crawlspaces that do exhibit mold conditions.

International Residential Code

408.2 Openings for under-floor ventilation. The minimum net area of ventilation openings shall not be less than 1 square foot (0.0929 m2) for each 150 square feet (100 m2) of underfloor space area. One such ventilating opening shall be within 3 feet (914 mm) of each corner of the building. Ventilation openings shall be covered for their height and width with any of the following materials provided that the least dimension of the covering shall not exceed 1/4 inch (6.4 mm):