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RE: Have you heard of watering your foundation?

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I have heard it as gospel that lime does not work for structural foundations, despite the fact that the highway guys seem to think it works quit well. I think the real issue might be cost rather than performance. The depth to constant moisture content in Houston is typically 8-14 feet, but of you could stabilize the upper 5-6 feet you would get rid of most the movement. The clay itself goes down 4000 - 6000 feet (in Houston), so piles to bedrock are a relatively expensive option.

 

Eric Green

 

-----Original Message-----
From: Glenn Otto [mailto:glenn(--nospam--at)libertyeng.net]
Sent: Monday, November 18, 2002 2:37 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: Have you heard of watering your foundation?

 

Do you Texas engineers observe any use of mixing lime with the clay or even pumping a slurry of lime into fissures?  Peck mentions this in his textbook.  Sounds like it would be expensive for single family dwellings.  What about using a geotextile to wrap an influence area beneath the foundations to keep a constant moisture content?  How deep is that geological formation typically? 

 

Glenn C. Otto, P.E.

LIBERTY ENGINEERING, P.C.

 

-----Original Message-----
From: Davis Parsons [mailto:dparsons(--nospam--at)msc-engineers.com]
Sent: Monday, November 18, 2002 12:55 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Have you heard of watering your foundation?

 

I was asked this question by my brother who is building a house in the Dallas area. I am a structural engineer in New York state and my response was- What? Why? I have not heard of this practice and neither has anyone I work with. The people he has spoken to (who are not engineers) saythat if you don't water the concrete it somehow loses strength and cracks. The only thing I can figure is that the clay soil there has not been preconsolidated by glaciers as it has here and the moisture is kept up to prevent consolidation and settlement of the house. Am I on the right track?Bruce C. Trobridge PE
Senior Building Structural Engineer
NYS - Office of General Services
(518) 486-1749 


North Texas has a large area of expansive clays with tremendous shrink-swell potential.  Geotechnical reports commonly give PVR (Potential Vertical rise) estimates for our soils. The Woodbine formation which runs from just on the east side of Fort Worth in an ESE direction can have a PVR of up to 8 inches. Due to our expansive soils, it is common practice to "water your foundation" on a weekly practice to prevent the soils from drying out. Soaker hoses should be laid along the foundation and used every two weeks during a dry spell.  The intent is to ensure a constant moisture condition around the perimeter of the foundation to reduce the shrink-swell potential.
 

--
Davis G. Parsons II, PE RA AEI
a practical architectural engineer
in Fort Worth, Texas