Movement - Symptoms, Causes, and Repair Solutions...
Symptoms of Foundation Failure
The most obvious indicators of
foundation movement are:
- Diagonal cracks in interior wall
finishes at the corners of doors and windows.
Cracks may also occur at the intersection of walls and ceilings,
and at the intersection of wall surfaces.
- Doors bind or do not open or
close properly. The gap between the top the doors and the adjacent
door frames will not be uniform.
- Windows bind or do not open or
- Cabinet doors do not close properly.
- Floors are not level.
- Cracks in exterior brick.
- Cracks in the concrete perimeter
beam. (Look at the concrete
beam below the siding or brick along the perimeter of
- Separations of wood trim at the
exterior corners of your home above brick.
- Separations of the brick and the adjacent wood surfaces at the sides of garage doors.
- Separations of the brick and the adjacent wood surfaces at the sides of the chimney.
Causes of Foundation Movement
Your home’s foundation is
designed to transfer the weight of the structure and contents to the
underlying soil or rock. In the
southern United States most foundations constructed today are slab-on-grade;
however, pier and beam foundations are still used in certain
situations and many older homes have pier and beam foundation systems.
Swelling and shrinking
of expansive soils underlying your home’s foundation are the primary
causes of foundation movement throughout the south.
Expansive clay soils swell when soil moisture levels increase and
shrink when moisture levels decrease resulting in lifting or settlement
of your home's foundation.
The second most frequent
cause of foundation movement is consolidation of improperly compacted
soil or rock fill, which can cause portions of the foundation to settle.
Because your home’s
foundation transfers the weight of the structure and contents to the
underlying soil, your foundation moves when the soils move.
If the foundation moves uniformly and does not deflect or become
unlevel the foundation is performing as designed.
If some parts of the foundation move more than others then the
foundation is undergoing differential movement.
It is this differential movement that damages your foundation and
the cosmetic finishes throughout your home.
Limiting Differential Movement
Because soil moisture
variations cause swelling and shrinking of the soils supporting your
foundation anything you can do to minimize those moisture variations will
also minimize foundation movement. The
three most common things you can do to minimize foundation movement are:
- Water your lawn and the areas
adjacent to your foundation uniformly during dry
- Make sure that surface water cannot
pond against the perimeter of the foundation.
The soil at the foundation perimeter should be higher than the
surrounding soils so surface water will drain away from the foundation.
- Large trees or extensive
plantings of shrubs in close proximity to the foundation can result in
drying of the soils under the perimeter of the foundation.
The shallow roots of these trees and shrubs extend under the
foundation and decrease soil moisture levels.
Normally trees should be planted at a distance from the
foundation equal to their mature height. If existing trees or
shrubs are affecting the stability of your foundation, a barrier
trench can often be installed between the trees and foundation.
Plumbing leaks beneath your foundation can cause lifting of portions
of the foundation. In extreme
circumstances excessive moisture may cause a loss of bearing capacity and
result in foundation settlement.
Foundation Repair Procedures
Minimizing foundation movement
normally involves underpinning the foundation with deep piers, correcting
poor drainage or both. Deep
piers are designed to extend below the active surface soils to areas less
affected by season moisture variations.
Piers transfer the foundation loads to those deeper, less active
soils. The vast majority of registered professional engineers
specify deep drilled, steel reinforced, cast-in-place concrete piers.
This is the same pier design used in
the construction of commercial multi-story buildings and highway overpasses.
foundation repair techniques
are marketed. Segmented
concrete piers, driven steel piers and helical piers are the most commonly
used alternative repair techniques. Be
sure and check with a registered professional engineer familiar with soil
conditions in your area before choosing an alternative repair method.
Confused about foundation repairs?
Call our office 512-443-2920
to request any of the following free publications:
"Preventing Foundation Movement"
"Comparing Foundation Repair Techniques"
"Comparing Foundation Repair Bids"