3 ways to replace foundation vents

Tips on building, sealing new screened unit

Q: This concerns the cement foundation air vents on a ranch-style house. The wire mesh coverings over the foundation air vents have rusted leaving an open space that poses a risk for various rodents entering the crawl space. How do I replace these wire vent coverings? The wire mesh coverings appear to be cemented into the foundation. –Paul F.

A: Unfortunately, you’re probably right. Many types of foundation vents are installed into the stemwall as the concrete is being poured, and they can be tough to replace. You basically have three options, the first of which is typically the easiest:

1. You can cut out the old screen as close to the foundation as possible, and then build a new screened vent that will fit into the old opening. Use a moisture-resistant material such as cedar, redwood or pressure-treated wood to construct a simple box, then staple galvanized wire hardware cloth to the back side. Fit the box into the old opening, and seal it in with a bead of clear silicone around the edges.

2. If your floor sits on top of the stemwall, you may be able to install a new, prefabricated vent into the siding above the old one. This requires cutting through the siding and sheathing to create a new access hole into the crawlspace, and you have to make sure that there is no plumbing, wiring, framing lumber or other obstructions in the way. You also need to block up any underfloor insulation so that it doesn’t cover the new vent, and then cover up the old vent with a foam block or other material.

3. You can have a concrete cutting company come out and cut out the old vent entirely, then cement in a new vent of the same type.

Q: My husband and I are new homeowners. We bought a 1977 townhome that still has its original furnace. I say that because we had to install an access door to even get good light to look at the furnace. I cannot find where the furnace vents are at to replace the filter, and am thinking about replacing the furnace altogether, as it looks deathly old. How do we go about finding out what kind of furnace we need in order to replace it? –Jill F.

A: The person you need to talk to is a licensed heating and air conditioning contractor. You can find them in the Yellow Pages under "Heat" or "Heating," but if you can, try to get a personal recommendation from someone you know. You can ask around among friends, co-workers, etc., and also check with your local utility company and your homeowners insurance company.

Between all of them, you should come up with a couple of names. I’d like to see you contact at least two of them, so you have different opinions and different options to consider, as well as different estimates to compare.

As far as the type of furnace you need, that depends on a couple of different things. You need to determine whether the fuel source will be electricity, natural gas or propane. If you just need heating, then you’ll be looking at a furnace only. If you need cooling as well, you’ll be looking at either a split system that provides both heating and cooling, or a heat pump.

A good heating contractor can give you all the options for location, efficiency levels, types of air filters, and other options such as add-on humidifiers. Compare your estimates closely, ask for local references of past customers, and verify the contractor’s license number, insurance and past claims history with your state contractor’s board.

Q: My sister has a louvered door in her basement (furnace room) and her dog got shut in and chewed two of the slats to the point they need replacement. Any ideas as to where I can find replacement slats? She lives in the Washington, D.C., area. She has been to the local chain hardware stores and they want to sell her a new door — she’s not hip to that. –Ted D.

A: Unfortunately, the slats in a louvered door are made by the door manufacturers or one of their suppliers, and are sized to fit the specific door. They are also installed as the door is assembled, and are trapped in slots in the frame members, which makes them difficult to remove and replace.

Since this is a door for a furnace room in the basement, which is louvered simply to provide air for the furnace, if you don’t want to replace the entire door then my suggestion would be to cut out the damaged slats — and perhaps a couple of additional ones — and then cover the hole with a louvered metal vent, of the type used in gable-end walls. Or you can custom-make your own vent with a wooden frame and 1/4-inch hardware cloth, sized to fit the opening in the door. Either one will provide the necessary air flow for the furnace while still closing up the hole in the door.

Remodeling and repair questions? E-mail Paul at paulbianchina@inman.com. All product reviews are based on the author’s actual testing of free review samples provided by the manufacturers.

Contact Paul Bianchina:
E-mail E-mail Letter to the Editor Letter to the Editor


Comments