4 ticking timebombs of poor home workmanship

Let the buyer beware; a plethora of problems can plague houses for sale. Experts point to sloppy and even dangerous construction, lamenting poor workmanship by do-it-yourself homeowners and even some professionals. Here are four areas that experienced contractors and home inspectors point to as problem-prone.

1. Paint

Byron Johnson, a general contractor in the greater Seattle area, sees a lot of what he calls "quick and dirty" exterior paint jobs. Johnson blames a lack of attention to the two critical requirements of a good paint job -- preparation and application -- whether due to cost-cutting measures for new construction or rush jobs to spruce up resales.

Preparation is key. "The surface has to be clean," Johnson says. "Loose paint needs to be scraped and the wood primed for the paint to adhere." And as for application, just spraying paint onto the side of a house is not enough -- it won't make complete contact with the wood. "The paint needs to be back-rolled (or brushed) to break the surface tension of the paint and force it into the wood fibers," he adds. Otherwise, the paint won't last, even if it looks right for the short term.

2. Drains

Home inspectors also come across lots of messy work. Howard Maxfield, an inspector in the Seattle area, says he's seen a number of drainpipes that run uphill. Unless your world is upside-down, those pipes are going to eventually plug. The recommended downhill slope for a drain is a quarter inch per foot.

3. Vents

Another common problem is improperly vented exhaust fans, according to Maxfield. "They run them into the attic rather than cut the hole in the roof and vent them outside," he says. Moist air from inside the house needs to be sent outside, not into the attic, where it needs to stay super dry. Otherwise, you could end up with mold and mildew problems.

4. Decks

Maxfield warns that DIY homeowners often make serious, hazardous errors when building decks. Because they often don't take out the required building permits, errors are neither detected nor corrected. If you're planning to buy a house with a deck, look closely at the deck construction. A deck should be framed with pressure-treated wood and have diagonal blocking between joists, as well as blocking over the beams.

The ledger board -- a board attached to the house and from which the deck joists hang -- should be anchored to the house with 3-inch lag screws, 16 inches on center, alternating top and bottom, and set into the house's rim joist or wall studs (not just the half-inch particleboard sheathing). This assures you that the ledger won't pull away from the house under the load of the deck. The ledger must have flashing to keep water from entering the wall.

Maxfield sees two other danger-areas in DIY decks: posts-on-piers and handrails.

• In most cases, posts should be set in poured-concrete footings, not 12-by-12 pier blocks; the footings should be either 16-by-16 or 18-by-18, and one-foot deep. The smaller pier blocks don't provide the necessary lateral stability.
• Handrails can be another issue. You must be able to grasp them, which means they cannot be constructed from a 2-by-4 or 2-by-6 set on the flat. It also means those boards cannot be set vertically unless the top edge has been shaped to fit the curve of the hand.

These are just a few of the problems you might find. When you're house-hunting and see that work has been done beyond the original construction, ask if there were permits for the work. Then study the project with a careful eye, and consult with a trusted professional if anything raises suspicion.