Preventing Moisture Intrusion
Monitor the Exterior
Planters: Check any planting beds adjacent to the foundation of your house because planters are built in a way that traps water, which may infiltrate hidden areas of your home. The structure around the planting beds acts like a dam and traps water. Flower planters should never be installed up against a house’s exterior wall.
Puddles: Puddles and areas of standing water are not good. The ground surface beneath decks, porches and other parts of a house that are supported by posts or cantilevered structures should be checked, especially if you have a sprinkler system. The ground should not have any low-lying areas but should be sloped so that water will not collect and puddle there. Settled backfill allows water to collect next to the foundation wall and penetrate the house’s foundation.
Gutters & Downspouts: Downspouts may need adjustment. Water from the roof reaches the ground through gutters and downspouts or by flowing directly off roof edges. Because downspouts create concentrated sources of water in the landscape, where they discharge is important. Downspouts should not discharge where water will flow directly onto or over a walkway, driveway, or stairs. The downspouts on a hillside home should discharge on the downhill side of the building. The force of water leaving a downspout is sometimes great enough to damage the adjacent ground, so some protection at grade, such as a splash block or a paved drainage chute, is needed. In urban areas, it is better to drain downspouts to an underground storm water drainage system, if there is one, or underground to discharge at a lower grade away from buildings. Water that flows directly off a roof lacking gutters and downspouts can cause damage below. Accordingly, some provision in the landscaping may be needed, such as a gravel bed or paved drainage way.
Check with local authorities to determine if your home is in a flood-risk zone. If it is, check with local building officials. Higher standards than those set by national agencies have been adopted by many communities.
The Federal Emergency Management Agency (FEMA) and the National Flood Insurance Program have established and defined five major flood-risk zones and created special flood-resistance requirements for each. For a flood map, visit www.nachi.org/go/femamaps. Improperly designed grading and drainage may aggravate flood hazards to buildings and cause runoff, soil erosion and sedimentation in the zones of lower flood risk, according to the Interflood Zone and the Non-Regulated Flood Plain. In these locations, local agencies may regulate building elevations above street or sewer levels. In the next higher risk zones, the Special Flood Hazard Areas, and the Non-Velocity Coastal Flood Areas (both Zone A), the elevation of the lowest floor and its structural members above the base flood elevation is required. In the zone of highest flood risk, the Coastal High Hazard Areas (Velocity Zone, Zone V), additional structural requirements apply.