Sources of Water Intrusion (into Your Crawl Space)
Every part of your home on the exterior is designed to drain water down and away. Roof shingles, gutter, siding, the gap between the foundation and the siding, weep holes, kick out flashing, and much more. Why?
The basic building blocks of our homes are wood and water is incredibly damaging to lumber. Water will weaken the lumber and cause it to rot. In addition it can promote the growth of mold and fungus which drastically increase the rate of degradation. Water in a crawl space will also invite pests into a warm, damp, dark environment; exactly the type of environment in which they thrive.
Common sources of intrusion are caused by plant life near the walls of your home retaining water and moisture in the soil, cracks and poor seals around the foundation, but the most common cause is bad drainage due to gutter placement. If your down spout is terminating near the base of your home without adequate grading to drain away then you are inviting water to stay and enter your foundation.
The second most common source of water intrusion is from inside your home. Many homes have small, long lasting leaks under their kitchens and bathrooms that go unnoticed for long periods of time. The wood sheathing under the flooring will degrade and rot slowly until it is noticed. After the squeaks, after the slight give when you step, but just after the sagging is noticed, that is when you will realize you have a much larger problem.
Home inspections should be performed every 3-5 year to ensure your home is not slipping into disrepair due to an unnoticed issue in a rarely visited part of your home.