Friday, December 19, 2014

Heave vs. Settlement : Up vs. Down, know your symptoms.

If you are experiencing foundation problems, it is very important that both you and your contractor know what is going on with your house, and the proper technique to fix it.  Misdiagnosing leads to improper repair plans, improper repair techniques, and the headache of that foundation movement will continue.

1) Signs of Upheaval

What is Upheaval?

Upheaval is the upward movement of a structure or foundation caused by expansive soil or (in other parts of the country) frost. Frost heave occurs when water forms ice layers in the soil. Expansive soil or rock heave occurs when there is an increase in water content in the soil. When the soil has an increase in moisture content, it will swell pushing the house up.

What does Upheaval Look Like?

The biggest key to diagnosing upheaval is compression.  When things move up, they will compress.  The trickiest part of diagnosing upheaval, is that you will usually see compression and separation.  Things will compress in the area of the upheaval, and separated from the stable portion of your house.  While parts of your house might appear to be dropping, it is actually because of the uplifted area of your home.

 

Broken Foundation from uplift (plumbing leak)
Drywall compression from Upheaval
Drywall compression from Upheaval




What causes Upheaval?
As we said above, an increase in moisture or frost.  The increase in moisture usually comes from one of three areas.  1) Poor Drainage  2) Plumbing Leaks   3) Tree Removal.  Tree removal can cause heave as the water that the tree was absorbing is no longer being absorbed, and therefore saturates the soil. 

How is Upheaval fixed?
There are few ways of fixing upheaval, and many of these are experimental.  If you are experiencing upheaval due to plumbing leaks, it all starts with fixing your plumbing.  If poor drainage is key, then improving your drainage or installing a drain system can fix it.  Soil injections using a product such as Condor S.S. have proven to be effective under certain circumstances.  However, the only guaranteed way to truly fix this issue is to underpin the entire foundation, and lift it higher than the soil can possibly swell.  This will suspend your slab higher than the soil can go, and not allow it to cause any further issues.  It is by far the most expensive form of foundation repair, but also the most effective.

2) Signs of Settlement

What is Settlement?
The downward movement of a building structure due to consolidation of soil beneath the foundation.
 
What does Settlement Look Like?
These are the classic signs everyone looks for.  Stair stepping fractures etc.  But the big key is shearing and separation.  The biggest difference between settlement and upheaval is the fact that upheaval "smashes" and settlement separates.

What causes Settlement?
This is the opposite of upheaval, so usually it occurs due to a lack of moisture in the soil.  I can also come from: erosion of the soil around the home, improper compacted fill under the home, an excess in moisture where the soil has become too soft to support the home, loose tension cables,and soil compaction due to the weight of the home.

How is Settlement fixed? 
There is only one true fix to settlement, which is underpinning.  In some cases, if you are experiencing settlement due to moisture loss, increasing your watering in that area, installing a drip irrigation system, installing root barriers, or removing the vegetation from that side can help, but it's not a guarantee.  If you are experiencing settlement due to any other factor, underpinning is the only cure.  

Thanks for reading! Stay informed!
Brian

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