Exterior

Most basement water infiltration problems can be attributed at least in part, to poor exterior drainage. The grading near the building is the first line of defense against water infiltration. Remediation of the grading will often eliminate basement moisture issues.
Unless you attend to gutters, downspouts, grading and so on, you must expect that the water will eventually come inside.
Buyers who take possession in the Winter months are often unable to carry out necessary repairs and re-grading until Spring. This is unfortunate, but does not reduce the potential for leakage.

Excavating and waterproofing an entire foundation is usually the last resort to deal with moisture issues and can be quite costly. Interior french drains are another option where exterior waterproofing is not a viable option such as an older rubble foundation where the exterior surface is not smooth and consistent. Older terra-cotta clay tiles or weepers can collapse or become blocked by silt build-up or tree roots and need replacement. Consult a specialist if problems develop.

Ensure that the grade (dirt, grass, asphalt, interlocking brick etc.) is at least 6 – 8 inches below any bricks or siding to prevent moisture from wicking up and into the building structure.

Often, on older homes, aluminum ventilated soffit is installed over solid plywood. Generally a visual examination cannot determine if there is adequate ventilation under the aluminum soffit. Resulting ice damming and associated leakage can cause damage in the attic, walls and basement.

Basement windows will leak if you allow snow or water to rise up over the frames as a result of poor drainage or inadequate window wells.

Exterior

Gutters and downspouts
Gutters or eaves trough collect water from roofs and (should) discharge it through downspouts or drain pipes, well away from the building walls or other structural support features – columns or posts for instance.

If you allow downspouts to discharge water against or near foundation walls, window wells, windows and so on you will significantly increase the likelihood of water penetration into below grade areas. Often downspouts that discharge near the junction of a driveway and a paved drive will allow water penetration under the asphalt, concrete or interlock -eventually causing damage, settlement or heaving.

Ensure all downspouts discharge at least six feet from the building. Rigid extension pipes work but you have to move them each time you want to mow the grass and they are often difficult to site where they won’t be in the way. The soft, roll out type doesn’t work well in cold climates as they freeze easily.

When installing extensions, only use rigid PVC or ABS pipes (three or four inch diameter is usually adequate). The corrugated, black pipe used as a perimeter drain at foundations is popular – however as it has holes in it, the rain water falls out before it reaches the discharge point – for this application, the pipe is useless! Creating a French drain or soakaway is often a successful alternative.

Do not allow downspouts to discharge onto lower roof shingles. The constant flow of water, over the same area, will cause premature wear and creates the potential for leakage.

Rain barrels
Rain barrels are a good idea if you need to collect water for your garden. During heavy periods of rain, barrels can fill to the overflow point in a matter of minutes. For this reason, you must however ensure that the overflows are treated in the same way as normal downspouts and discharge at least six feet from the building walls.

Grading
Grading relates to the topography of the entire land surrounding the building and includes paths, patios, walkways, drives, lawns and so on. Its important that the grade slopes away from the building walls at a rate of about an inch in four feet, for at least the first six to eight feet. This also includes areas under decks and porches. Often you can achieve this by simply importing dirt or topsoil. Gravel, sand or other porous materials are generally not recommended as the water falls through and remains close to or against the building walls.

In some cases you will have to dig a ditch or swale to make the water run away from the building or you may have to install window wells.

Trees
Large trees near houses can cause significant damage to foundation walls, floors, drainage pipes and roofs. Be sure to trim branches well away (six feet minimum) from roofs, chimneys and walls.

Root infiltration into perimeter drainage tiles at the footing level can cause water to rise against foundation walls, creating a potential for leakage. In homes with septic systems, roots will clog weeping tiles and may cause system failure.

In the event that large limbs or even the tree itself needs to be removed – always use a qualified contractor. Even small branches can be very heavy and it takes an expert to drop a tree into a confined space.

Homeowners are generally poor at judging height (against what it will look like on the ground) and the contractors fee will almost certainly be less that the repair costs you’ll face, if you fell a tree onto your house or car!

Doors and windows
Wood doors and windows need regular attention by way of painting or staining and caulking.

Its seldom worth replacing windows unless they’re falling apart or aesthetically – they drive you crazy! Repairs are almost always less costly than replacement and the heat loss savings declared by some manufacturers may not be as significant (or achievable) as their claims might suggest.

Vinyl or aluminum windows often only need cleaning with soap and water. If you have a brick or stone home that has steel lintels over the windows and doors, you must paint the lintels with a metal rust proofing paint (Tremclad for instance) – otherwise the rust may permanently stain the vinyl.

Attend to the joints of all clad windows – especially at the corners. Loose or missing caulking here may allow water to get inside the cladding and rot the wood underneath.

Operating windows need attention to mechanisms and tracks. Sliding window tracks can be lubricated with a silicone furniture polish.