Corroded or leaky gutters and downspouts can cause water to pool around your foundation and seep into the house. If it's just a matter of fixing a loose joint in an aluminum gutter, for instance, you can avert disaster yourself. Just wash the damaged area with denatured alcohol and apply a sealant, such as Geocel's Instant Gutter Seal ($3.50 at hardware stores), says Tony Cobb, founder of the National Rain Gutter Contractors Association
. If you have steel gutters that are riddled with rust holes, you're better off replacing them. Contractors typically charge a minimum of $150 to $300 for minor repairs, while $750 gets you all-new gutters, installed on an average-size home at $4 to $5 per lineal foot. The job will last 20 to 25 years, says Cobb. If you have copper gutters, always try repairs first. The soaring cost of the metal can make them prohibitively expensive to replace. Plus, their distinctive look and 70-year life span make them worth preserving.