Mike Shadid Foundation Consulting Inc. Newsletter

Winter 2013

 

 

 

 

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Value Proposition

Each week I inspect 10-15 basements and there is not much that I haven’t seen after 22 years in the business.  When I am asked to inspect a basement there is usually a concern about seepage or structural condition.  Typically water on the floor, or wet walls, or cracked blocks are a sign that something is not right.  My job is then to figure out what failed and make recommendations to correct the defects.  They may include do-it-yourself or contractor repairs. 
Sometimes conditions that were caused at the time of construction can be monitored with proper documentation.

Last week I saw a basement that needed $20,000 of repair work.  The gutters were full of debris and the sump pump was not powerful enough to handle the necessary volume of water.  During rain storms water overflowed the gutters and ran down the basement walls toward the drain tile.  Without enough capacity to empty the drain tiles water backed up into the basemen.  Silt and other debris clogged the drain tiles back up into the basement.

 

Because the drain tiles did not drain the soil around the foundation became saturated and exerted pressure on the walls causing them to bow and break.
What strikes me is that almost always the problems could have been prevented with simple maintenance

In the end it was a system failure that resulted in the damage.  If the homeowner had cleaned the gutters, or purchased a more powerful sump pump the homeowner would be able to afford a new car. Instead they are getting brand new wall braces for Christmas.

1. Clean gutters would have diverted water from the foundation.
2. Soil pitched away from the structure would have diverted water away from the foundation.
3. An adequate sump pump would likely have been able to keep the drain tiles clear. 

For the price of my inspection the owner could probably have prevented the damage. 

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Case Study

realtor called me after a recent home inspection.  The question regarding the foundation was that the palmer valve had been removed from the floor drain.  This was indicated as a significant defect because if the sewer backed up the debris could become lodged in the drain tiles.  Some of the interior drain tiles appeared to have been recently replaced.  I scheduled an appointment to inspect the foundation.  The owners were asked to provide any documentation regarding the recent drain tile installation. 
It turned out that a foundation repair contractor with a consulting division was hired to evaluate a seepage condition. The contractor replaced two walls of the interior drain tiles connecting them to the floor drain where the Palmer valve was missing.  The charge to replace 60 feet of interior tile was $6,000.  The contractor provided a $600 discount, as the estimate was $6,600.  The price per foot came to $100.
Most communities in the Milwaukee area require a building permit to replace drain tiles.  Further, if interior drain tiles are replaced the permit requires that the Palmer valve be removed; the drain tile lateral to the floor drain must be blocked with concrete. 

A sump pump must then be installed to divert water above grade away from the basement.
The contractor who was also the consultant installed the drain tiles without a permit.  He had not blocked the drain tile lateral, as regulations require.  Since the Palmer valve was not present a sewer backup could have clogged the new drain tiles rendering the $6,000 project useless.
I recommended a sump pump be installed to meet building code requirements.  (The Palmer valve lateral was sealed with concrete). Proper planning is the key to completing the least costly, effective appropriate repair.
Typically 60 feet of interior drain tile should cost between $3,500 and $4,200.  A sump pump normally can be installed for $1,800 to $2,000.
The owners could have had a proper installation, including a sump pump for the money they spent.  Instead they had to hire another contractor to close the Palmer valve lateral and install a sump pump.  The entire project cost nearly $8,000. 
If the job had been properly bid the cost should have been $6,000 including the pump.  In addition, the closing was delayed two weeks until the second contractor completed the sump pump installation. 

 


How Soil Conditions Relate to Foundation Problems

Foundation structural or seepage problems are most likely to occur in clay soil conditions. Clay is ground up rock that occurred as the glaciers moved through our area.  Because clay is a cohesive soil it absorbs water easily.  This causes the soil to expand and increase in weight.

It is very important to divert water away from the foundation because as soil becomes saturated lateral earth pressure is exerted against the foundation walls.  This can cause foundation walls to move inward.  Concrete walls are not elastic and when they move they break.  When walls break they become unstable and lose the ability to provide support for the structure. 

Because clay does not drain well water can enter the basement through the floor / wall joint, floor cracks, or through the walls. 

This characteristic is the reason drain tile systems that divert water away from the foundation and floor are required to keep them dry and prevent excessive hydrostatic pressure on the walls and floor slab. 

During dry periods clay soil loses moisture content and decreased in volume.  On the surface large cracks may develop and the soil may pull away from the foundation walls.  The soil is likely to settle toward the wall rather than away from it. 

These conditions make seepage more common after prolonged draughts because previously properly sloped soil can cause water to accumulate around the foundation. 

If clay soil under footings dries it can shrink allowing the footing to settle and cause structural cracks.  In extreme cases the upper structure can distort enough to make windows and doors difficult to open and close.  Floors can slant in addition to other possible structural damage. 

Clay is formed in areas that were wet for thousands of years. Much of Milwaukee was a swamp and was drained as the city developed in the early 1800s’.  Sandy soils are formed from glacial activity as ice slowly crushed rock and pushed aside silty topsoil.  Clay is most common in areas east of Calhoun Road – which is a sub continental divide. 

Division Road in Germantown was named because it is closely follows a boundary between sand / gravel to the west and clay to the east. 

Sandy soil conditions are also common in the Kettle Moraine north of Milwaukee and south west of the metropolitan area.  This type of soil generally drains water very well.  Sump pumps may not run often because water does not flow into the drain tiles as it is diverted away from the foundation into the earth.  Structural displacement issues are not common in sandy soils and gravel areas.

Of course it would be too easy to use broad geologic structures to predict foundation problems.  Low areas in sandy soil may flood during heavy precipitation.  Most importantly, frozen soil drains very poorly.

 

     

 

In Conclusion

The most effective way to prevent clay from becoming saturated is to divert, direct, and control surface water away from the foundation perimeter. Much of this can be done by the homeowner and can prevent thousands of dollars of damage. 

  1. Clean the gutters
  2. Make sure downspouts are attached – and long enough to get water away from the foundation

Make sure that ground slopes away from the foundation at a pitch of no less than ½ inch per foot for 5 to 6 feet.

Once structural problems have occurred finding the most appropriate corrective action require expertise and an unbiased opinion.  Excavating a basement wall may be necessary – but it should be one of the last resorts. 


Mike Shadid, December, 2013

The facts, information and opinions contained in this newsletter should not be construed as a warrantee or guarantee of any type.  They are based upon observations and information obtained over 30 of doing basement inspections.  Equally qualified persons may come to different opinions based upon similar facts and observations.  Any person relying on opinions contained in this newsletter do so at their own risk.  Each basement is unique and general opinions contained in this newsletter may not apply to all basements.  If you have a problem with your basement you should have it inspected and not rely on general opinions in this newsletter.