House foundation failure
House foundation failure
(OP)
A client has a house in Florida built 35 years ago on a cypress head. One section of the house has settled 5" with the accompanying cracks and distress in the tie beams, vertical walls and adjacent sidewalks and porch. A cypress knee has grown 12" in a flower bed at the main entrance. Piers, grouting, demolition and replacement and other remedies have been suggested by contractors. No soil analysis has been made on this structure, but a neighbor did have one and sinkholes were ruled out.The client will not report this to the insurance agent for various reasons.
The question: Anyone out there have design/construction experience in this area they would like to share/
The question: Anyone out there have design/construction experience in this area they would like to share/






RE: House foundation failure
reagrds
sc
RE: House foundation failure
Cyprus head is not just a stump. It is huge and they can get very large with roots emanating from the trunk area outwards and they stay close to the surface.
Cyprus trees thrive in wet and still water areas.
My question, how did they miss this stump? And how deep and large is it?
Many issues come to mind. Fixing this problem is not going to be cheap and repairing to insurance may not be avoided.
I also have a concern with the quality of the construction since the contactor covered up or built on the stump.
I suggest that competent engineer look into this situation, prepare a report aided by geotechnical analysis and feasible and proven repair method that will keep the structures integrity during and after the repair work is done.
Good luck
RE: House foundation failure
I agree it could not have been missed during construction or by a geotech as a major problem. Now that the house is built it will provide problems for very long period of time. I don't believe that killing the monster is an option as this will lead to decomposition of the roots that are under the house. By the same token letting it continue to grow will also cause problems as it draws moisture from the ground.
As you need to get the point of bearing for the footings below the zone of influence by the root system. Ie you need to get to a point of relatively stable moisture content. On the face of it piers would be the way to go, providing the existing footing system can be used with piers.
As Lutfi said you really need to get a local structural engineer (PE) to look at it on site and to devise a method of repair.
regards
sc
RE: House foundation failure
Thanks again for sharing your expertise.
RE: House foundation failure
The problem appears to be the growing instead of the dying effect of the stump. In such a case, simply drill holes and put tree poison into the exposed roots.
If the foundation is grouted up sufficiently ( holes drilled at an angle below the foundation and cement grout injected) the effect of rotting tree stump can be mitigated.
Care have to be exercised not to damage any services like drains, cables etc). The injected grout simply help to spread the load over a bigger area with a hardened soil mass containging a potential big void.
RE: House foundation failure
Thanks for the imput. Some contractors have recommended replacement at a cost of $80-$100/sf. One contractor gave the client an estimate of $40-$45K for a compination of grouting and pile support at the perimeter, with no guarantee against future failure.
So, it has become one of the classic engineering problems associated with constuction failures. Your comment on the water and sanitary lines is appreciated;I'll have to have compentent contractors standing by.
For those of you watching this, I will give you some feedbck as the project develops.
RE: House foundation failure
What I see as an the issue is typically the soils cypress are found, are black organic muck. Sounds like the site was not properly pepaired. The Florida building code prohibits building on organic matter. The builder should be invoved with the remediation and desisions since he has liability exposure.
RE: House foundation failure
You are absolutely right. All signs point to no or little site preparation. I will try to track the builder down.
Smwpe
RE: House foundation failure
Or, he can build another.
RE: House foundation failure
Or: Keystone Foundations
RE: House foundation failure
Have the builder provide another lot and move the house.
Or, he can build another.
For a 35 year old house?
The first sentence of smwpe's original post says, A client has a house in Florida built 35 years ago on a cypress head. I think it's a little late to go after the original builder...
A wise lesson I learned early in life: "Think twice before speaking once." I'd suggest a careful reading of the original post before submitting comments -
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: House foundation failure
Thanks to all of you for your recommendations.
RE: House foundation failure
RE: House foundation failure
Didn't use helical piles, just schedule 80 3" steel pipes. We got a bearing pressure of approximately 5k when we stopped.
Cost was around $1800/pile. I'd use $2000 for a budget figure. Spacing no more than 6' o.c.
RE: House foundation failure
We used it quite offen in Florida where small layers of much were found. To my knowledge we never had any settlement or failures of any kind.
We used it once to correct a swimming pool that had settled over 5". The pool builder had not removed all the muck and the shallow end settled.
RE: House foundation failure
Thank you for the suggestion. I have a client with a swimming pool settling, and this may be the answer. Do you have any info or references you would care to share with me?
RE: House foundation failure
RE: House foundation failure
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: House foundation failure
Exactly right. Had trouble in the past with lighter members, and there is always a nagging worry about corrosion with the soil,water mix that may not show up in a geotech evaluation..
RE: House foundation failure
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"