Changing Water Levels Means Changing Soil Conditions

Serving Greater Denver, Colorado

The Spring season brings more than just changes in water restrictions or flood and fire dangers, it effects how the soil under homes behaves. According to the USDA, many areas in the Front Range already experience unstable soil conditions and changes in water levels will cause soil expansion and contraction.

When summer comes into full bloom in Colorado, temperatures rise. We swelter in our cars, or toss and turn at night. Have you noticed how much more often you have to water your plants and flowers? Obviously, the heat keeps the ground dry, but most of us don't realize what dry heat really does to the soil and how that affects our homes—especially under our foundations.

In Colorado, we have 255 days of sun on average, which tends to dry out the top layers of soil. With clay, the top layers will become hard and impermeable and the bottom layers will remain moist.

This can explain why you might have a moist, musty basement, but be having trouble keeping your lawn from burning. It's also one of the reasons why we experience flash flooding.

Expansive Soil

Most soil in the Front Range can be classified as a swelling soil. This means that the soil contains a high percentage of certain types of clay that absorb vast quantities of water. This can cause the soil to expand 10% or more as moisture enters it, usually during winter snow melt and spring run off. The soil then exerts tremendous pressure on foundations, slabs, and other structures. Now, this soil also contracts when the moisture evaporates during our hot summer months, causing extreme differences in the pressure being generated on your foundation, driveway, or patios.

Expansive soil exerts more pressure on your foundation than 10 women standing on each other's shoulders, balanced on a single stiletto heel! Ouch! It's the same pressure exerted on a domino if you stacked 20 Nissan Altima's on top of it!

Expansive soils do not swell and shrink if the moisture content Sprinkler lines should be installed away from the house. Landscaping is essential part of solving any foundation problem, so be sure to ask your foundation specialist and engineer
for recommendations!

Resolving Structural Issues Due to Expansive Soils

Unfortunately, cosmetic repairs such as new paint or stucco will not fix problems caused by expansive soil. That's why it's important to have a professional service company to come in to your home with engineered work that is backed up with warranties and guarantees to protect your investment. The service company should hire an independent, professional Geo-technical Engineer can make a site inspection and perform laboratory tests. After analyzing your particular situation, he can make recommendations specific to your property.

Only engineered structural solutions can promise real results. Make sure that the contractor is properly licensed and the equipment is certified. Ask your foundation repair company if their solutions have ICC reports. The International Code Council (ICC) only gives approval reports to structural solutions that have passed rigorous tests.

Some indications that you are dealing with expansive soils are:

• Foundation cracks
• Heaving and cracking of floor slabs and walls
• Jammed doors and windows
• Ruptured pipelines
• Heaving and cracking of sidewalks and roads

If you are experiencing any of these problems, it's important to be proactive. The longer that expansive soils exert pressure on your foundation, the more costly and difficult fixing those problems can be.

Special Note:

You and your neighbor share soil—if your neighbor is experiencing problems, chances are so will you. So, ask the builder for the subdivision soil report. The report should indicate if expansive soils are present and what the builder has done to minimize their effects. NRCS soil survey reports can also help to determine the presence and location of expansive soils.