Vapor to blame for concrete chipping

Q. My concrete block foundation is 28 years old, and some of the brown solid color latex stain is flaking and peeling, both inside and out. I can handle that, but in a few blocks on the outside large chunks of concrete are popping off the blocks. Some are an inch deep, or nearly so. Would that be due to moisture? And does that mean that the blocks are filling with water? I tried filling the popped areas with mortar without success.

JOE FALZONE, St. Paul

A. It is unlikely that the blocks are full of water, but to find out, drill a hole in a block near the floor, and possibly high up, too. If you get water, you can drill holes here and there to drain it. More important are the chunks of concrete popping off the blocks. This is called spalling, where water vapor gets inside the block and condenses, then freezes and expands, popping off chunks willy-nilly. It also happens with bricks, where a small flaw allows water vapor to get inside the brick, then condenses into water that freezes.

Filling in the spall areas didn't work because you did not use a bonding agent before applying the mortar. To do it right put a bonding agent on the spalled areas, then fill with Top 'n' Bond, which is designed to go on in thin layers. Bonding agents are found where concrete products are sold and other outlets.

Q. I have old Jeld-Wen windows, about 20 years old. I have to replace some of the jamb liners where the tiny ropes have broken. I checked with the manufacturer who said they do not make anything older than 15 years old. Is there any place else I can find them?

UNHAPPY

A. Ah, you've got to hand it to these manufacturers. They set up their replacement schedules so you have to buy new windows from them. Good marketing, eh? But hope springs eternal: There is a wholesale outfit called Brosco (Brockway-Smith) that carries everything for the house, including windows, except lumber. Go to an independent lumber dealer who will show you a catalog that contains two pages of balances for windows. If you find one that works, the dealer will order it for you. You can probably keep the catalog. In the meantime you can hold the windows open with a stick.

Q. I had my builder install zinc strips at the top of my roof to help prevent the growth of mold, lichen, moss, and algae. I think the builder got the idea from one of your columns. But now the strips, which are exposed 1 1/2 inches beyond the topmost shingles, are bubbling up, and look terrible. What's wrong?

TED PARKER, Edgartown

A. Hmm. I have never heard of such a thing. I have recommended zinc strips many, many times. To elaborate, when water runs over the strips, it picks up a bit of the zinc and distributes it downroof, preventing the growth of mold and algae. They may be defective, and aggravated by the salt in the air and water. You might try getting another set of strips. Using another kind of metal such as copper, which is deadly to mold and algae, is not a good idea because the copper will turn to that familiar green color, which is OK on gutters, flashing, and other outside features, but not when it drips down the roof.

Q. I am redoing my driveway. What are the merits of poured concrete and hot top? The driveway is not very big.

LINDA, Norwood

A. Both are concrete (one is cement based, the other is bituminous). Both stand up well, and both should be applied over 6 inches of crushed stone for good drainage. I think poured concrete - 6 inches deep with steel reinforcing and expansion joints every 10 feet or so to prevent cracking - is better for you. It may be a bit more expensive but it is better for the environment because it contains no oil, while hot top is 100 percent oil except for the stones in it. This is not to denigrate hot top, which is good and probably more economical, but shorter lived.

Q. My patio has many concrete patio blocks - green, red, and buff - which are in good shape but look rather dull and dingy. How can I restore their color and clean them up?

RALPH DuPONT, Albany, N.Y.

A. The green and red may have faded over the years, but you can try this: Simply power wash them. The color may come back and they will be clean. Or, put a cup of bleach in a gallon of hot water and wash the blocks. That may restore the color. And finally, turn one block over and hose it off; you will find the colors brighter, so you can turn them all over. Considerable work, but you will have a new patio. But this all depends on whether the blocks are mortared.

Q. In 2005 we resided our house, and new storm windows were installed throughout. Our 1914 windows were in bad shape. We can afford now to replace them. But two major national-brand window dealers each state they cannot/will not install their double-glazed windows and leave the three-year-old storms installed. They state the storms "must go," that leaving them up would invalidate the window guarantee "because of a high failure rate when storms are left on" (explanations included heat buildup between the storm and its window, and/or inadequate ventilation).

It seems to me that leaving storms on simply provides better insulation from heat and cold, and better sound insulation as well. We live on a busy street, and keeping the windows and storms closed reduces noise considerably. Your take?

CAROL McKEEN and JOHN DUNTON, Waltham

A. Oh, for goodness sake. Leave the storms on. I have written this many times and have never gotten a squawk from any window people. You are right on all counts, including sound transmission. It may be true that heat can build up between the storm and main window, but this is cured by the presence of weep holes at the bottom in the storms. Just make sure they are there and they stay open. One of the reasons the window people are so skittish about their windows is that they are double-glazed, and are very sensitive to temperature extremes, and that is why they are warranted generally for only 20 years, which is no time at all for any window. So what if they don't tilt out? Let the window washers worry about that.

You have the right idea. With all the technology in the world today, you'd think they'd come up with a double-glazed window that will not fog up within 20 years. Especially for windows that cost $700 to $1,000 each! How about two layers of glass, one in a wood frame and the other a metal clad insert on the same frame? I've had some of those for 30 years without failure or fogging.

Throwing away three-year-old storms is a colossal waste. But here's an idea. If the big wheels are so all-fired eager for you to remove the storms, why don't you ask them to take the cost of those storms off their already colossal bill. Think they'd do it? I doubt it.

My windows are single-glazed but well weather-stripped, and are 100 years old. Both my storms (True Channels, the best) and my inside storms are 30 to 40 years old. They ain't guaranteed and they ain't broke. It is wonderfully quiet in my house, which is also on a busy street. The inside storms are glass, not plastic, and of course they are not made anymore.

Globe Handyman on Call Peter Hotton is also in the Styles Section on Thursdays. He is available 1-6 p.m. Tuesdays to answer questions on house repair. Call 617-929-2930. Hotton also chats online about house matters 2-3 p.m. Thursdays. To participate, go to Boston.com Hotton's e-mail is photton@globe.com.