Foundation Vents for Dummies

You might be surprised (we're not...) by how often content-farm freelancers manage to botch DIY instructions because, to be perfectly frank, they have no earthly idea what they're talking about. Take, for instance, the half-baked job multiple DotD winner Lacy Enderson performed when attempting to tell people, "How to Install a Foundation Vent" at the mother site, eHow.com.

Just for grins, we've reposted (above) the image that accompanied Enderson's article, chosen by Lacy herself, to give you an idea of just how unconscious people like her are. You can never be certain where people like Enderson get their information, but – based on her instructions – we suspect that this time they were from an article on building a house over a crawl space. Unfortunately, Lacy seemed to think that the same instructions apply to retrofitting vents...

According to Lacy, all you need do to ventilate your crawl space is,

1. "Determine how many foundation vents [you need]..."
2. "Select locations on the 2-by-12 rim joist between two subfloor joists..."
3. Cut openings with a jig saw...
4. "You will probably have one [vent] every 3rd or 4th bay. The bay is the 16 inches between each floor joist."
5. "Slide a foundation vent into each space. Attach the vents to the rim joists with... [nails]..."

Point of information, Lacy, the space between joists is 14½ inches, not sixteen (assuming the joists are 16 inches OC). That's not to mention that Enderson's example is seven vents for a 1000 ft² foundation. That would call for two on each wall, not "one every 3rd or 4th bay." Lacy's suggested spacing would place five or six vents on each of two walls, with none on the other two sides.

As instructions go, they're fairly OK – even Lacy couldn't screw those up... except that foundation vents are normally found in the foundation, not the rim joist. You see, if you have to cut the rim joist you also have to cut through the exterior siding. If the house has a brick veneer, that's gonna dull the hell out of the jigsaw blade, Lacy! You'd want to cut holes with a masonry hammer or pull out one concrete block per 8 x 16 vent. Another point of information: many building codes no longer require crawlspace vents, and modern building techniques suggest leaving the foundation intact and installing a moisture barrier. Our guess is that homeowners are better off paying attention to sources like This Old House than people like an 18-time winner of our Dumbass of the Day.

copyright © 2018-2023 scmrak

DDIY - VENTILATION