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posted: 7/10/2011 12:01 AM

Home repair: Seal or replace black-spotted deck?

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Q. Five years ago our deck was enlarged using composite decking, Home Depot brand. The deck is at ground level on the west side and gets a fair amount of sun. In the spring when the snow melts, large and small black mold or mildew spots are present over the entire deck; a few spots develop during the summer. Every spring the deck is cleaned with a cleaner, which bleaches the spots out after using it on the worst spots two or three times. Should I use a sealer to prevent recurrence? If so, which sealer or alternate solution would you recommend? Or should I replace with a better quality composite decking?

A. Home Depot's composite Veranda ArmorGuard Decking is a blend of cellulose and polymers that is protected with a PermaTech finish which has a warranty against staining and fading and is resistant to molds and mildew. You should check with Home Depot about the length of the warranty and what can be done about the problem you are encountering. The manufacturer offers some cleaning suggestions. If you have followed them, you may have a claim.

Q. I have been replacing the roofing on most of my house with "architectural grade" asphalt shingles, which I hope will outlast me at 75. However, on a recent trip to Europe, I saw no asphalt shingles. Most roofs were red tile. In other regions of France, Germany, Czech Republic and Switzerland, there might be black slate areas and three thatched roofs and metal on four barns. It looks like tile roofs hold up the best and slate has a few problems. New slate roofs have little metal clips sticking out to hold them. New tile roofs have a layer of insulation and a waterproof surface and slats over this to hold the tile. The tile is not fastened but stays there by weight. One person slides the tiles up to get a foothold on the slats to get to antennas and such. I started to wonder about becoming the only Bristol resident with a red-tile roof.

I will try to look on the Internet about loading weight, cost of shipping (a real project killer) and such. Although none of the regions mentioned have winters as cold as minus 40, they do get to minus 18 C. Do you have any ideas about tile roofs: availability and such? I still have the front roof to do on my 1850 farmhouse.

A. Tile roofs are very common throughout Europe and have been for centuries. They are an almost "forever" product, but are not found in the U.S. outside of California and a few other areas in the arid south. Europeans are generally more concerned about the durability and longevity of products than their cost, whereas we are more cost-conscious and more prone to just throw things away when they are no longer are in vogue. I do not know why these roofs have not had the same success in the U.S., except perhaps because they are far costlier.

You may have noticed that in Greece and other Mediterranean areas, the bottom rows of the tiles are weighted down with large rocks because the strong winds can lift them right off the roofs, with a deleterious effect on higher rows. If you are serious about using tiles for your house, you would have to find them in the far West, as I know of no dealer in the East.

Q. I completely enjoy your column and advice/direction. You appear to have vast experience in homebuilding and repair, and your communication style is excellent. And ultimately, your advice has the user doing what's right for the home.

We moved into our new home seven years ago, and thought we were so clever to have a patio poured, before the grass went in, so the concrete truck would not damage anything. We did due diligence and worked on the concrete crew frequently. My husband works for the municipality and has a good understanding of the process and dos and don'ts. So we laid a healthy layer of gravel and tamped down till the cows came home.

We had a large patio laid -- 23 feet long by 13 feet wide. However, when all is said and done, it seems that we did not prepare as well as we thought. The night we poured the patio, there was a heavy storm, and water seeped into the basement through foundation cracks. On the new home walk-through, we had previously identified many foundation cracks with the builder, and he did repair all of them after the storm/leakage event.

We have never had a drop of water in the basement again -- and we want to keep it that way. However, on the concrete patio, the 13 feet to one side of the stoop has settled dramatically; it has dropped about four inches. The 10 feet to the other side has dropped also, but only about one inch. We are worried of course that during each rain, water is draining back against the foundation. Over time that can't be good, especially considering the foundation's history. The patio is not pinned to the home. The concrete does have rebar in it. What are your thoughts?

A. Thank you for your nice comments. Unfortunately, the patio was not anchored into the house foundation. So when it rained heavily, the backfill against the foundation became wet and began to settle because it is loose earth, and the grade seems to be very flat. The amount of water that saturated the soil caused the leakage through the foundation cracks. The earth having settled left an open void under the portions of the patio bridging the backfill. Unsupported, the concrete settled, and in one section, broke as shown on the photos you sent. You can see the hollow under the stoop, which, if it hadn't been tied to the foundation, would have suffered the same fate. No amount of repairs will work unless more material is added to the settled backfill. If you can find a contractor who does mud-jacking, since the slab was reinforced with rebar, it may be possible to raise it in its entirety, as I see no other cracks than the one on the left side of the stoop. The mud-jackers would fill the resulting voids with slurry.

Other options are to remove and replace the concrete and to have the parts of the slab bridging the foundation excavation cut on both sides of the stoop and removed, more gravel added and thoroughly tamped manually (not mechanically, in order to avoid too much pressure on the foundation walls). Rebar should be drilled into the foundation. New concrete should be poured to replace the sections cut out and to top off the remainder in order to obtain a gentle slope away from the foundation. The new concrete should contain an additive to ensure proper bonding with the old. You should also add soil as needed in all low areas against the foundation to prevent saturation of the soil, which would apply undesirable pressure on the walls.

Q. What is your recommendation for clogged gutters? I get leaves and other junk regularly that clog the downspout holes. I recently read that you recommended DCI's Flo-Free Leaf Guard with commercial gutters. I have the residential gutters. Would this product work for residential gutters? I remember that you were not a big fan of the gutter gimmicks that were previously sold. Are these covers easy to install? Or do you recommend they be professionally installed?

A. I have installed DCI's Flo-Free Leaf Guards ( on both our residential and commercial gutters. (I had residential gutters with commercial downspouts installed on the one-story side of the house to minimize the effect.)

Flo-Free Leaf Guards come in both sizes. Of all the gutter covers I have seen or used, these seem to be the best ones. They were easy to install and do not require specialized professional installation. They are made of a plastic matrix that does not seem to interfere with the flow of water in heavy downpours, as some of the other solid gutter covers with slots or holes would appear to do. I once told the representative of a manufacturer of solid plastic covers that I thought that water would fly right over the covers during a summer gusher, and he was honest enough to agree. I haven't had that problem with the DCI covers.

Your other option is to replace your residential downspouts with commercial ones, but make sure that whoever does it will change the gutter outlets to 3-inch-by-4-inch commercial ones. As my old friend Joe "the gutter man" told me when I was a general contractor in the Washington, D.C., area in the 1950s and 1960s, "Heck, Henri, a dead pigeon would flush through them." He sold me on their use, and that has proved to be a solution to their clogging.

Follow-up: A few weeks ago, a Chicago reader wondered why a small amount of water would periodically drip from the conduit of a second-floor ceiling smoke detector that seemed to be covered with plenty of insulation. I was surprised that she referred to a conduit -- a plastic or metal tube through which wires are run -- because residential wiring is usually done by Romex and does not require to be run in a conduit. At the time, I called the city of Chicago and asked to speak to an electrical inspector or code official and was told that this was not possible. How is that for public service! I was referred to and followed the various prompts to the parts of the city of Chicago electrical code. If anyone wants to waste time, please try it. All I got were explanations of various terms that are obvious on their own.

Unable to get an answer, even after calling the city again and insisting on talking to a code official and being told again that this was not possible, I answered the reader's question as if a conduit was not required. A knowledgeable Chicago-area professional pointed out that a conduit is required in all electrical installations in the city.

So why is condensation running in the conduit? There must be some part of that conduit that is exposed to cold air in the attic. Warm, moist air from the second floor must be entering the conduit through the smoke detector, where it condenses and drips back down. The insulation should be checked to make sure that the conduit is not exposed anywhere in its run. It is also possible that more insulation is needed over the conduit if the conduit is in its upper level, leaving it more vulnerable to cooling.

A valuable shop accessory: I recently refinished a maple dining room table in our garage. Most garage lighting is not adequate for fine jobs that require meticulous steps. I found the Wobblelight invaluable. A fluorescent bulb is mounted on top of a broad base that is loaded with steel weights that make the light always come back upright if knocked about. It can be moved around as needed as the job progresses. You can see it at A great gift for the handyperson.

• Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via email at

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