Moisture is the #1 Enemy of Any Home (Part 1)
Approximately 90% of all structural building failures are caused by moisture. This problem is clearly the #1 enemy of any home. Regardless of age, style, or location; moisture is extremely damaging and all homeowners, home buyers, or real estate professionals need to be able to recognize it.
To begin understanding moisture, it is important to understand what the structure of a house is. There are 4 parts to the buildings ‘super’ structure and they are the:
1. Foundation
2. Floors
3. Walls
4. Roof
Moisture can easily enter these spaces from either outside or inside of the building. Sometimes moisture is visible on the surface of building materials making it easy to recognize, but most of the time it is located in concealed spaces behind the finished building materials that are not visible to the untrained eye. The longer dampness remains unchecked the more damaging and expensive it becomes to remedy.
Moisture Problems – Landscaping
Let's first look in the basement or crawl space seeking moisture, figuring out its source, and providing solutions to the problem. The most common dampness in below grade foundations originates from outside the building. Moisture intrusion is caused by inadequate control of surface and ground waters. The results can be discolored walls, seepage on the floor around the perimeter of the foundation, or a completely flooded basement.
So what causes these conditions?
The most common cause of basement moisture is improper landscaping. Simply put the earth grading is sloped towards the foundation. This is called negative slope. The first step in managing surface water is to make sure the earth slopes away, positive slope, from the foundation on all sides of the building. Even the smallest depressions or settlement of soil can trap water allowing it to dampen the walls and stain the foundation.
Although type of soil can have an impact on whether surface water will enter the building, there are 3 common grading defects that should always be corrected. They are:
1. Flat or negative slope
2. Settled backfill
3. No drainage swale
Landscaping is always a problem, but is not the only thing on the outside of the home that causes moisture intrusion. Controlling exterior surface water can be quite a bit more complex than just landscaping. There are many situations that the landscaping looks just the way it should, but below the surface it really isn’t. Some soils let water flow through it very readily, permeable; typically this does not trap water on the foundation. And some stops moisture, impermeable; this can actually be sending water towards the house. On the surface it looks like the earth is sloped away from the foundation, but below its not.
This condition is often masked by topsoil, decorative rocks or wood chips. So discovering this problem is more difficult than just looking at the slope of the earth. It might take moving some dirt, rocks, or chips to see the true lay of the land.
Most of the time, correcting these grading problems will include hauling in dirt, raising the soil along the foundation and gently tapering it away from the house. However, there are circumstances that will actually require digging out the dirt, lowering it on the foundation, and re-shaping the land. The core principal is that water must move away from the foundation and drain off the building site.
Once the movement of surface water is changed it may impact other homes and this could open a homeowner up to a lawsuit. So, before beginning to re-landscape you should always check with the city and the neighbors; thoroughly explaining the plan and seeking each of their approvals.
Moving some dirt around doesn’t sound like too big a deal…but there are other concerns before starting this type of project. One of those would be making certain the earth isn’t placed too high on the foundation. If the earth is too close or contacting the wood framing, this would cause a different type of moisture intrusion. It would not disclose itself in the basement or crawl space, but it would rot out the structural wood framing. For that reason the building code requires a separation between the top of the foundation and the finished earth grade.
This is Part 1 of a series dedicated to identifying sources of water that could damage your home. Part 2 of the series will describe moisture damage caused by both exterior structures (hardscaping) and gutters.
Source: Cities' Inspection Website
As usual, should you be interested in buying or selling a home, or for any further information regarding your home, please contact me, Karen Borden, your North Alabama Real Estate Professional!
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