Texas Foundation Watering and Maintenance Guidelines
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During extreme drought, North Texas will go through watering restrictions put in place by your city or county. Please read your city or county watering guidelines. The main restrictions are normally limited to your yard. Most restrictions allow you to water your foundation with a soaker hose for up to one hour every night.
The main goal is to not allow a gap to be between the house's slab and the dirt. You may need to water 30 min to an hour or more initially to close any existing gaps. Then back off to shorter times and maybe go to every other day to keep the gap closed. Watering the yard as much as possible is also highly recommended. Helping maintain a consistent watering program for the entire yard helps ensure you are protecting your slab.
North Texas’ expansive soils act like a sponge. As they absorb water, they swell and as they lose water they shrink. Soils tend to dry in the summer and absorb water (and swell) during the winter and spring.
As the soil around a house shrinks and swells with the seasons, the house and foundation will move up and down. As long as the foundation movement is not great enough to damage the house and/or foundation, most people do not consider the movement to be a foundation repair problem. If the up and down movement of a house foundation always returns the house foundation to its original level position, then damage to the house and foundation may appear and disappear on a regular basis as the seasons change.
If a homeowner wishes to stop seasonal house and foundation damage, the first course of action should be to follow a controlled watering program. By keeping the moisture content of the soil around the house foundation constant, foundation movement can often be stopped. This has been written to assist the homeowner in performing a simple foundation repair preventive maintenance program.
The goal of a foundation repair preventive maintenance watering program is to maintain a constant level of moisture in the soil around the house and foundation. The best way to water a foundation is to place a soaker hose from one to two feet from the edge of the foundation. Placing the hose a short distance from the foundation allows the water to soak into the soil evenly.
The hose should not be placed against the foundation. When soil has dried and cracked, water can travel along the cracks for several feet in all directions. If the soil around your foundation is dried and cracked, then water placed next to the foundation will run through the cracks and accumulate at the bottom of the grade beam (the thick portion of the foundation that is under the exterior walls). In some cases, an accumulation of water in the soil at the base of a foundation can cause the soil to lose some of its load-bearing capacity. If the soil loses enough load-bearing capacity, the house will sink into the ground.
Obviously, it is necessary to water more during hot, dry weather and less during cold, damp weather. The amount of water required to keep a foundation stable during the summer can be surprisingly large. A single large tree can remove as much as 150 gallons of water, or almost 20 cubic feet of water, from the soil each day. Shrubs and other plants can also remove large quantities of water. During persistent hot dry weather, it may be necessary to water a foundation daily. Watering should supply enough water to keep the moisture content in the soil under the foundation constant. If the amount of water applied is only enough to keep the surface damp, the watering program will not work. Obviously, the homeowner is the only one who can weigh the benefits of controlling foundation movement versus the increased size of the water bill.
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CAUSES AND MODES OF FOUNDATION MOVEMENT
Movement As A Result Of Seasonal Moisture Changes
Foundations that are built directly on expansive soils that are subjected to non-uniform changes in the soil moisture content can suffer from differential movement. During extended periods of dry weather, the expansive supporting soil shrinks causing foundation settlement. During extended periods of wet weather, the expansive supporting soil swells causing upward movement of the foundation (upheaval). Localized site and environmental factors that promote or limit the flow of water into and out of the supporting soil as well as non-uniform distribution of the expansive soil under the foundation affect the magnitudes of the movement (either upward or downward) at different locations of the foundation. It is important to understand that it is differential, not the total movement of the foundation that causes damage to the structure. In other words, the performance of a foundation that moves up and down uniformly with the changing seasons is superior to a foundation where the movement is not uniform.
LEAKING PIPE
Slab/Foundation Movement Caused By Plumbing Leaks:
A slab-on-grade foundation acts as a vapor barrier by resisting soil moisture variations due to evaporation moisture loss.
UPHEAVAL TO A SLAB-ON-GRADE slab soil from rainfall. Under optimum conditions, the soil moisture under the slab will achieve a degree of equilibrium. When a plumbing leak occurs under a slab, the moisture equilibrium is distorted. As moisture is added to the soil from the leak, soil and foundation movement often result. The type and degree of movement depends upon soil type and expansiveness, soil density, soil moisture content prior to the leak, the length of time over which the leak has occurred, the quantity of moisture being added to the soil over a given period of time and a few other factors.
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Typical examples:
1. If the soils are expansive and were dryer than optimum prior to the leak and have a high density, the foundation/
slab will heave (move upward) in the vicinity of the leak and corresponding damages will be apparent in the structure. In this example, the soil will probably not contract significantly after the leak is repaired, which will
result in a permanent dome in the slab. 2. If the soil is at optimum density and moisture prior to the leak, there is an opportunity for the soil to contract. It is
possible, but not probable, that the slab will regain its original elevation profile because clay soil expansion/ contraction generally does not follow a linear progression as moisture is added and then reduced. The slab could be
permanently left above or below its initial elevation. 3. Should a leak occur under the slab where the soil is of very low density, the additional moisture often lubricates the
solid clay particles and causes consolidation of the support soil prior to leak repair. After the leak is repaired under this example, the slab will often "dish" or settle (move downward) even more.
NOTE: Concrete and steel will often develop a "stress memory" after deformation that will not allow the slab to return to its original shape. This may be the result of soil or concrete chips filling cracks in the slab, which prevents the slab from "coming back together" completely. In a post-tensioned slab, stress in the post-tension cables may resist the tendency for the slab to move back into place.
Foundation Upheaval Caused by Poor Drainage: Since additional moisture can cause expansive soils to swell, areas of poor drainage near the foundation can cause the soil under the foundation nearby to swell, resulting in upward movement of the foundation.
Settlement As A Result Of Poor Pre-Construction Compaction: Slab-on-grade foundations depend upon the uppermost soil layer(s) to provide sufficient bearing capacity to support the structure and to keep the foundation stable. If the bearing soil was insufficiently compacted prior to construction, the foundation is subject to settlement as the supporting soil consolidates.
GLP Foundation Repair 817-889-4306 www.GLPDFW.com
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