Q. Zoysia grass is coming up through my sidewalk along the edges. How can I prevent that?
Because Zoysia grass has underground roots that are likely to go all over the place, dig a V-groove along the edge, making sure to cut any roots between the sidewalk and the lawn. Then sprinkle vinegar in the V-groove. That should keep the V-groove free of any growth for the summer, and maybe into next spring. If you see any of the edging grass dying, then forget the vinegar.
Skip the polish
Q. When I bought some used wood furniture, I painted it flat black. It looked good, but I wanted a slight sheen, so I applied furniture polish, and it came out badly streaked and looks terrible.
OK, don't panic. Clean the polish off with paint thinner; two applications may be needed. Once the black is nice and flat and not streaked, never use the polish again. To get a sheen, apply two thin coats of an oil-based semigloss polyurethane varnish.
Q. We like red cedar clapboards and want to leave them untreated. We were told they will remain OK for years. Another source said they can split and probably will curl in time. What can we do to keep them good looking?
Clapboards can split, treated or not, and curl, but proper nailing will prevent both. Use stainless steel nails, and nail them 1/2 to 5/8 inch from the bottom of the clapboard, every 12 inches. If you don't like the way the red cedar weathers, apply one coat of an oil-base semitransparent stain. A dark color will not show the dreaded cedar bleed.
The front of my house is red cedar clapboards, stained dark brown, and has stood up quite well. I used small galvanized siding nails, and a few have popped after the wood contracted, but I simply pull them and renail an inch or so away. A few clapboards had to be replaced in the past 30 years, but it still looks pretty good.
Q. My 50-year-old concrete retaining wall still works well, but we recently had a concrete cap poured. It was supposed to be sealed, but it was not, so we will have to do it ourselves. Someone mentioned Drylock as a sealer. Would that work?
Yes, Drylock is a cement-based paint and is the best thing to use, both on the top and the side. But concrete does not have to be sealed.
Q. The thick seat cushions for my outdoor pipe furniture are giving up the ghost and need replacing. I have been everywhere, but all the stores say they cannot sell the cushions separately. Where can I find such cushions?
Look no more. I found exterior cushions, from slim pillows to ones 4 inches thick – universal seats, chaise longue, firepit bench, deep-seating cushions, chair/rocker, settee/swing and ottoman “box” cushions – on page 69 of the Improvements catalog. Call 800-642-2112.
Q. My heating ducts are in the cellar, and the small ones that go to individual rooms are between the joists. How can I insulate them? The trunk lines (big rectangular ones) are under the joists. How can I insulate those?
It is difficult to insulate round ducts in the space between joists. If possible, use 1-inch duct insulation and wrap the round ducts, then buy a stapler that staples on itself so you can seal the wrap with a standing seam. Then fill the space between joists with 6-inch fiberglass insulation. I think you can get away with stapling the paper backing directly to the bottom of the joists.
You can wrap the trunk lines, too, and if it's hard to wrap the tops, just wrap three sides, and seal with Gorilla tape or staple the insulation to a joist. You have to play these things by ear.
Peter Hotton: firstname.lastname@example.org