Sand, vinegar can kill sidewalk joint weeds

Q The bricks in my sidewalk are tight, without mortar, but not tight enough to prevent weeds from growing in the spaces in summer. I kill the weeds, but what should I fill the joints with to prevent future growth?
JULIA BROCKLEBANK, Falmouth

A The best thing to put in those joints is sand; buy a masonry sand which is as fine as you need. Stone dust will do, too. You can't stop the weeds from growing except by sprinkling white vinegar heavily into the joints in the spring and when they sprout. The only way to stop them in their tracks is to take up the bricks, lay down stout black polyethylene plastic, perforate it for drainage, and put the bricks back. This might keep the weeds away for up to 5 years or so. I personally would prefer digging out the weeds and adding vinegar.

Q My atrium (French) door opens onto my deck, with about a 1-inch drop. For 20 years, this has worked well to keep out water, but now I'm getting water under the fixed door. The doors are directly under the eaves of a low-sloping roof, with no gutters and no overhang, so water comes right down the wall and door face and onto the threshold, which is level, not sloped like a threshold should be. How can I fix it?
PHYLLIS GREEN, Brookline

A The deck's too close to the threshold, the threshold is level and not sloped so it holds water, there is no overhang along the roof line, and there are no gutters. There are several things to correct this mess, but first check the threshold; it has held water so long that it may be rotting or at least punky. If so, replace it or fill voids with an epoxy filler (Minwax is a good brand ). To keep the water away, you can put up gutters, perhaps only in the immediate area. As for lowering the deck to create a 7 1/2-inch step instead of a 1-inch one, this is a project of last resort.

Q Should vinyl siding be power washed?
JAMES SLAVIN, Taunton

A No. The strong stream from power washing is very likely to get behind the vinyl and water behind vinyl will stay forever (almost), causing decay and other odious things. The same goes for aluminum. Another reason for the taboo is the direction of that powerful flow: usually upward (and under the vinyl). How to get a power washer to aim downward is a good question. But a reader from New Orleans said he does washing and other chores for the house and he and his men can reduce the pressure of the power washer, which he says works well to keep water out of the siding. And, he said, aiming the power stream is equally important in keeping water out.

Q I've had trouble filling a driveway crack that's 1/2 inch wide and 1/2 inch deep. A latex filler didn't work. Would an asphalt filler work?
SAM

A An asphalt filler will work better, but more important, the crack should be deepened, to at least an inch. Then install the asphalt with a caulking gun, pressing the gunk into the crack very compactly. Bring it up to the level of the driveway, then sprinkle sand on the new asphalt. The sand is primarily for keeping the asphalt from sticking to tires and shoes.

Q I have a glass salt cellar with a nice sterling cover that is stuck fast. It is friction fit, which makes it tougher to pull off. How can I separate those fused pieces?
OLD SALT

A Water is your best ally, and use it to dissolve the salt inside and out. Soak the cellar overnight in warm water to dissolve as much as possible . Then, use one of those rubber mats to get a good grip on the sil ver and pull and twist as you try to pull it out. The same goes for a twist-off top, but be careful not to squeeze the sterling out of shape. Once you get the parts apart, let them dry before filling with salt, and get into the habit of pulling the top off regularly so this does not happen again.

Here's another idea about why so many rooms above garages seem colder than others. Most cures for cold rooms add insulation wherever possible, especially on the garage ceiling, which is often as well insulated as any other wall or ceiling. But extra insulation doesn't always work.

So, Arthur Chapman called to suggest this: If the owner of the cold room has hot-air heat and keeps the door closed, not much warm air will enter the room, because there is no air return vent, a vent for the air to go out of the room, so the system keeps pumping but no more warm air enters.

There is a cure, Chapman said, without opening the door; cut an inch off the bottom of the door, which will provide enough vent space for cold air to return.

Thanks, Arthur.

Handyman on Call also appears in the Globe's Real Estate section on Sundays. Peter Hotton is available 1 to 6 p.m. Tuesdays to answer questions on house repair; call 617-929-2930. Hotton chats online about house matters 2 to 3 p.m. Thursdays, at Boston.com. Hotton can be reached at photton@globe.com.