Do It Yourself: Water-based caulks could be best bet
Q. I want to replace a lot of caulking around the outside of my house, especially around windows and doors where I suspect there are air and water leaks. Much of the old caulk is cracked, discolored, or has pulled loose. How do I clean the joints before re-caulking and what type of caulk should I use?
A. Some old caulk, especially silicone, retains enough flexibility to be pulled off in strips. Other caulks can get hard and must be removed by scraping.
To scrape, use a sharp 5-in-1 tool, which you can buy at most home centers or hardware stores. In addition to having a sharp blade several inches wide, this tool has a hooked side that can be used to pull out chunks of loose caulk.
If some caulk resists removal, you can sometimes soften it with a solvent such as 3M Caulk Remover. (If you can’t find a caulk remover locally, search for Chemical Caulk Removers on the Internet.) A heat gun on moderate-heat setting will also soften caulk, but extreme caution must be used around flammable materials, especially dry wood. A dangling electrical cord is also awkward and dangerous when used on a ladder.
When you have removed the old caulk, brush dirt and loose particles from the joints with an old paint brush.
The array of caulks at many home centers and hardware stores is truly mind-boggling, but it is not difficult to narrow down the choices.
Most do-it-yourselfers prefer water-based (latex) caulks that clean up with water, have little odor and are easy to smooth with a wet fingertip. Latex caulks can usually be painted within a few hours. Most latex caulks will adhere to many surfaces and some will last for many years. Check labels on the caulk cartridges for detailed information.
Silicone caulks are also a good choice, but most silicones are not paintable and must be cleaned up with mineral spirits; some users find them tricky to smooth.
Some professionals prefer urethane caulks, which have superior adhesion to most surfaces and are highly water resistant. Urethanes must be allowed to dry thoroughly before they can be painted, however, and full drying can take several days.
Q. A couple of the insect screens in our older house are damaged and we want to fix them. One screen has only a small tear about three inches long, but the other is badly ripped in several places (it was scratched by a cat trying to get outside). The screens are vinyl or fiberglass and are in vinyl replacement windows. What’s the remedy?
A. The small tear should be easy to fix. Buy a small tube of clear, waterproof cement or a small tube of clear silicone caulk. Remove the screen from the window and spread a small amount of the cement or caulk on the end of a flat stick or a plastic spoon. Hold a piece of cardboard over the tear on one side of the screen while you spread the sealer along the tear on the other side. When the sealer dries, it should hold the sides of the cut together, keep out insects, and be barely visible.
Severe damage to a screen usually means that the screening should be replaced. This is often not a difficult do-it-yourself job.
In many screens, except old wood-framed and some metal-framed screens, the screening is held in the frame by a flexible spline. The spline is like a thin rope, made of vinyl or similar material. The spline fits into a groove in the screen frame, holding the edge of the screening in place. If the spline is removed, which can be done with a small screwdriver or awl, the screening will come out.
You can buy vinyl or fiberglass screening at many hardware stores or home centers, along with spline and an inexpensive tool with a wheel on the end that is used to force the spline into the groove.
If you install new screening yourself, cut the replacement several inches oversize. Install the spline on one side and keep the screening taut as you work on the other three sides. When you are satisfied with the installation, trim off excess screen with a sharp utility knife.
There are a couple of other options if DIY doesn’t appeal to you. Some hardware stores offer screen-repair service, although you won’t find many home centers that want the work. Also, if you know who made or installed the windows, contact them and see if replacement screens are available.