"A contractor can install a plastic, vinyl shield on the existing joist and remove the ground cover. Also, closing the venting system in the winter and opening it in the summer helps."
Home inspector/engineer Harry Gross in Cherry Hill reminded me that we once talked about sealing off the crawl-space vents with vapor barrier and insulated walls as the best approach for this region.
But when there is a lot of moisture, as there may be 200 yards from the bay, there are two approaches to dealing with it, Gross said.
One is to channel any water that may enter the crawl space, preferably lined with a concrete vapor barrier, into a sump with pump for removal.
The other is to not have a vapor barrier (this allows water that enters to drain out through the porous sand), insulate the floors with a vapor barrier on the insulation and keep the crawl space well-vented to carry or dry out the moisture within the crawl space.
"So, basically, it is to choose how to minimize the moisture in the crawl and then properly deal with any moisture that makes it in," Gross said.
Thanks to both of you for your help.
Sump pumps. Tri-County Inspection president Jack H. Milne Jr. sent along a story about a client in Glassboro who had a sump pump with a backup battery that wasn't working when he tried it.
I'm relating this because he offered an explanation of the water-powered backup system we've been talking about since Irene hit us over the head in late August.
The system "uses water power to create a Venturi effect, a technology that's been in use for almost two centuries for many processes," said Milne, based in Morrisville, Bucks County.
"When fluid under pressure in a pipe flows through a constriction, the velocity of the fluid increases and a vacuum is created," he said. "For a water-powered sump pump, the vacuum draws water up into the pressured water stream and is discharged to the exterior."
The pressurized water is simply the home's water supply piped to this pump system. The only mechanical moving part is a float-operated valve to turn on the water supply.
"Since it's very rare to have a public water supply fail during a power outage, this is a very reliable system," Milne said.
If the water is supplied to the home from a private well, the well pump doesn't run without electricity and this system won't work, according to Milne.
The water-powered system installation results in a cross connection between the potable water of the home and the sump water. There must be a "back-flow preventer" device installed, so sump water can't travel back up the supply pipe and contaminate the potable water.
Milne said the water-powered pump system usually costs more to purchase than a battery pump system and typically involves paying a plumber to do the water-supply piping work.
The expense is probably worth it, considering the cost of cleanup in a prolonged power outage.
Information about manufacturers of these water backup systems is available on the Internet.
One more thing. Your homeowner's insurance provider probably offers additional coverage for sewer backup and sump-pump overflow.
Check into it, although I do caution that it might be best to have a reliable backup, because with too many claims, your policy can be dropped.
Website find: www.ifixit.com offers free repair manuals for a variety of products.
Questions? E-mail Alan J. Heavens at firstname.lastname@example.org or write him at The Inquirer, Box 8263, Philadelphia 19101. Volume prohibits individual replies. He is the author of "Remodeling on the Money" (Kaplan Publishing).