Seemingly small oversights and errors in do-it-yourself projects and home maintenance can have costly consequences.  A single misstep might mean that a job must be completely redone or that hundreds, even thousands, of dollars must be spent to solve the resulting problems.  Below are some of the most common mistakes that can easily be avoided.

MISTAKE:  Failing to apply grout sealer after laying tile.  Grout stains easily and is extremely difficult to clean.  After you grout your tile, whether on a floor, wall or countertop, wait three to five days for the grout to cure, then apply a solvent-based grout sealer.  (Latex-based sealers are less effective.)  Apply with a small brush or spray bottle and wipe off the excess.  Add a new coat of grout sealer every year and if the grout is in or near the shower, do it twice a year.  Helpful:  Environmental restrictions are making solvent-based grout sealer more difficult to find.  If it is not sold at your local home center or hardware store, try a specialty tile store.  Latex-based grout sealers are better than nothing, but you will have to apply three or four coats to get effective protection.  To clean grout that is already dirty:  Use a cleaner specifically made for grout, such as ZEP Grout Cleaner & Whitener, available at tile and hardware stores.

MISTAKE:  Applying a latex paint directly on top of an oil-based paint.  Latex paint, the most popular paint these days, will not stick to a surface painted with oil-based paint, which used to dominate the market.  Within weeks, the new coat of latex will begin to peel and you will have to strip it off and start again.  To determine whether existing paint is oil of latex-based, wash a section with soap and water, let it dry, then swab it with rubbing alcohol.  If some paint lifts off, it is latex; if not, it is oil.

If you must apply latex paint on top of oil paint, first apply a coat of deglosser, also known as “liquid sandpaper”.  Check the instructions on the deglosser.  Some are effective only if you paint within hours of deglossing.

MISTAKE:  Using the wrong caulk or not preparing properly to caulk  Caulking is one of the cheapest, easiest do-it-yourself tasks, but it is still possible to make mistakes that lead to serious problems.  Some homeowners fail to thoroughly clean the surface that is about to be caulked and then the caulk bonds to the dirt and dust, not to the wood, metal or ceramic underneath, allowing moisture to get into the home’s structure.  Others use the wrong caulk.  Cheap caulks can fail in just a few years, and simple latex caulks will not take paint.  Wall trim often needs to be caulked before painted.  The best choice is a high-quality siliconized latex caulk or a letx-elastomeric caulk.  Either should last twenty years.

MISTAKE:  Painting metal without properly treating rust.  Most metal that is exposed to the elements will rust.  Painting over your home’s rusted metal doors, railings, fences, patio furniture or steel gutters only cloaks the problem.  The rust will continue to consume the metal.

Before painting any rusty surface, sand down the rusted area, then apply Ospho, a phosphoric acid product that retards rust.  Let it sit overnight.  The rusted areas should appear black by the next day, a sign that the rust has been chemically altered so it will not continue to spread.  Apply a coat of Rust-Oleum metal primer over the entire surface of the matal to prevent the spread of any rust that is not yet visible, as where there was visible rust, there is additional rust that cannot yet be seen.  Once the primer dries, you are ready to paint.

MISTAKE:  Not “exercising” water shut-off valves.   When the shut-off valves beneath sinks and toilets go untouched for years, mineral deposits can cause them to seize up and the valves cannot be opened or closed.  Often the only recourse is to hire a plumber to cut the valves out and replace them, at a cost of hundreds of dollars.  This will not happen if you shut and reopen water valves every six months.

MISTAKE:  Neglecting exterior door hinges.  The hinges on an exterior door can rust and seize up, causing significan damage to the door when it is used.  This typically happens to seldom-used doors, but it can happen to a front door while you are on vacation.  If you lubricate exterior door hinges once a year with a silicone spray, they will give you a lifetime of trouble-free sercices.  It is best to not use an oil-based lubricant as it can trap dirt in the hinge.  Open the door before applying the silicone to ensure that the lubricant gets inside the hinge barrel.

MISTAKE:  Allowing a garbage disposal to rust.  Rust can develop in a garbage disposal when it goes unused for as little as a week.  Pour a shot glass of vegetable oil into the disposal before leaving on vacation and it should stay rust-free.  When you return, pour a small amount of dishwasher detergent down the disposal to clean out the oil.