The blocks are brought to the site and laid by a mason with staggered joints.  If the joints are not staggered, the basement wall will have lower strength and it is a sign of . . . → Read More: The wet hollow block wall basements of Cleveland, Ohio]]> Basements are constructed with perimeter walls made with

1. hollow cement blocks, or
2. poured cement concrete.

Hollow block wall basement construction

The blocks are brought to the site and laid by a mason with staggered joints.  If the joints are not staggered, the basement wall will have lower strength and it is a sign of very poor workmanship.  After the blocks are laid, the hollows may be reinforced with steel bars and filled with a cement concrete to increase its strength and durability.  I am not certain if there is an easy method, for a typical home buyer or the second and the subsequent home owners to verify if the hollow block basement walls were reinforced or not.  If unreinforced, a hollow cement block basement wall is clearly inferior to a poured concrete basement wall.  The hollow cavities will provide a reservoir space for water which will eventually seep into the basement.  The unreinforced hollow block basement wall will have lower strength, durability and fire resistance.  The purposes and advantages of using hollow cement blocks is the speed and the cost savings using the the large sized blocks.  To meet the construction time parameter, a crafty home builder may decide that it is indeed desirable but not essential to reinforce the hollow blocks of the basement wall, particularly, if the applicable building codes do not explicitly require this reinforcement.

So, should a home buyer consider buying a home that has basement walls constructed with unreinforced hollow cinder blocks?  These basement walls which also act as retaining walls, will be weak in tension and are highly likely to develop cracks.  A poorly constructed basement is trouble and it is prudent to walk away from that home.

Hollow cement mortar cinder blocks used for basement construction

Concrete and steel reinforced block wall basement

Wet basements of Cleveland area in Northeast Ohio

Many homes in the Cleveland area of Cuyahoga County in Ohio have basements that are made of these hollow cement blocks.  I have seen several basements that have clearly visible whitish salt deposits known as efflorescence and patches of dampness; in summer .  One common reason among these homes for the damp basements is poor lot grading.

Jim LaRue, one of Cleveland’s best known home improvement and basement expert states in The Connection‘s article titled “Waterlogged basements defy usual explanations”,

I have seen as much basement water problems in brand new homes as I see in old ones.  My many years of basement investigations have persuaded me that we should not be using basements as living spaces and if we do, we should remodel them defensively.

Its estimated that 60 percent of U.S. homes have wet basements, and 38 percent run the risk of wet basements with mold.

Best time to buy a home

In the Northeastern part of the country, home buying and selling activity is at its peak range during summer and fall, when the rain and the snow are absent.  During these seasons, wet basement and leaky roof issues are likely to be less evident.  These seasons suit the home sellers and the commission focused real estate agents well.

According to Dr. Bruce Schantz, Professor of Civil Engineering, University of Tennessee, Knoxville and author of Wet Basement and Crawl Space Problems, Causes and Remedies-Tips for Homeowners and Home Buyers,

The best time to sign a home purchase contract is on a rainy day!

Waterlogged basement defy usual explanations

Click to enlarge this rainfall map of the June 22-24, 2006 storm.  This massive storm event caused some flooding issues in Broadview Heights, Brecksville, Solon, Sagamore Hills, Bainbridge, Twinsburg, Independence, Glenwillow, Oakwood, Bedford, Garfield Heights, Valley View etc.

100 Year Storm: A storm of a . . . → Read More: Flooding Issues in Cleveland Suburbs]]>

Rainfall Map for Solon Cleveland Suburbs-Click to enlarge

Click to enlarge this rainfall map of the June 22-24, 2006 storm.  This massive storm event caused some flooding issues in Broadview Heights, Brecksville, Solon, Sagamore Hills, Bainbridge, Twinsburg, Independence, Glenwillow, Oakwood, Bedford, Garfield Heights, Valley View etc.

100 Year Storm: A storm of a certain intensity and length of time that has a 1% probability of occuring each and every year.

500-1000 Year Storm: The June 22-24, 2006 storm poured 5.5″ of rainfall over a 4 hour period.  This storm damaged approximately 4, 580 homes and 48 businesses in Cuyahoga County.

What you need to know is that a typical stormwater collection system is designed for a 5 year to a 25 year storm!

Flooding in Brecksville

Reference: Flood of June 22-24, 2006, in North Central Ohio with Emphasis on the Cuyahoga River Near Independence By James M. Sherwood, Andrew D. Ebner, G. F. Koltun and Brian M. Astifan, Scientific Investigations Report 2007-5161, USGS and FEMA.

Related Posts:

Does your home need a backwater valve?

City of Solon Flood Zones Map-Click to enlarge

A Subject to 100-year flood. Base flood elevation undetermined.

AE or A1-A30 Both AE and A1-A30 represent areas subject to 100-year flood with base flood elevation determined.

AH . . . → Read More: City of Solon Flood Zones Map-Real Estate in City of Solon]]>

City of Solon Flood Zones Map-Click to enlarge

FEMA FLOOD ZONE DESIGNATIONS & EXPLANATIONS

Annual Probability of Flooding of 1% or greater

A Subject to 100-year flood. Base flood elevation undetermined.

AE or A1-A30 Both AE and A1-A30 represent areas subject to 100-year flood with base flood elevation determined.

AH Subject to 100-year shallow flooding (usually areas of poundings) with average depth of 1-3 feet. Base flood elevation determined.

AO Subject to 100-year shallow flooding (usually sheet flow on sloping terrain) with average depth of 1-3 feet. Base flood elevation undetermined.

A99 Subject to 100-year flood, with federal flood protection system (levee/dam) under construction. Base flood elevation undetermined.

V Subject to 100-year flood and additional velocity hazard (wave action). Base flood elevation undetermined.

VE or V1-V30 Both VE and V1-V30 represent areas subject to 100-year flood and additional velocity hazard (wave action). Base flood elevation determined.

In SFHA Areas in a “Special Flood Hazard Area” (or 100-year flood plain). Subject to 1% annual chance flooding. No distinctions have been made between the different flood hazard zones that may be included within the SFHA.

Flood Prone Area: An area designated as a “Flood Prone Area” on a map prepared by USGS and the Federal Insurance Administration. This area has been delineated based on available information on past floods. This is an area inundated by 1% annual chance flooding for which no base flood elevations have been determined.

Annual Probability of Flooding of 0.2% to 1%

B or X500 Both B and X500 represent areas between the limits of the 100-year and 500-year flood; or certain areas subject to 100-year flood with average depths less than 1 foot or where the contributing drainage area is less than 1 square mile; or areas protected by levees from the 100-year flood.

Annual Probability of Flooding of Less than 0.2%

C or X Both C and X represent areas outside the 500-year flood plain with less than 0.2% annual probability of flooding.

Annual Probability of Flooding of Less than 1%

No SFHA Areas outside a “Special Flood Hazard Area” (or 100-year flood plain). Can include areas inundated by 0.2% annual chance flooding; areas inundated by 1% annual chance flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; areas protected by levees from 1% annual chance flooding; or areas outside the 1% and 0.2% annual chance floodplains.

Undetermined

D Unstudied areas. Flood hazards are undetermined.

The revised and most current flood zones are available with FEMA.

Source:  The helpful City of Solon GIS Coordinator, Tim Howard.

City of Solon Ohio Basement Flooding Map

Basement fixtures below red line may need backwater valve to prevent basement flooding-Source: City of Worcester

Click on the backwater valve graphics to enlarge them.

Backwater valves are installed to prevent or reduce . . . → Read More: Basement flooding, wet basements and backwater valve]]>

Lower basement drains may need a backwater valve to prevent basement flooding. Source: Unknown

Basement fixtures below red line may need backwater valve to prevent basement flooding-Source: City of Worcester

Click on the backwater valve graphics to enlarge them.

What is a Backwater Valve?

Backwater valves are installed to prevent or reduce the frequency of sanitary and storm water backing up on the mainline through the lateral and flooding a basement.  This backing up condition is referred to as backflow.  Backflow can occur due to 1. obstruction and/or 2. the collection system reaching its capacity.

Who may need a Backwater Valve?

If your home is located on a sloping street and your home is at a lower level than other homes on that street, you may be subject to backflow. Folks who are considering a home purchase on a sloped street should carefully look into this location location location consideration, if feasible, in concert with an appropriate expert such as a plumber, home inspector.  Further, the best backwater valves and the backwater valve monitoring system are not inexpensive.  The above graphics, obtained from public sources, indicate a few configurations where backflow may be expected.

Backwater Valve Location

The location of plumbing fixtures in the basement does not always indicate the need for a backwater valve, unless these fixtures drain to the mainline by gravity.  In instances, where basement drains are pumped up to a upper drain and the pump outlet is provided with a check valve, a backwater valve may not be needed.

The backwater valve should be properly located and installed.  The backwater valve is installed as shown in the second figure from the top.  The backwater valve should be located upstream of the foundation drains or downspouts connected to the laterals, otherwise the homeowners may flood themselves.  Also the backwater valves should impact the basement drain only.  Homeowners should always consult an appropriate expert.

Backwater Valve Permit

You may need a permit from your local municipality to install a backwater valve.  I think municipal permitting becomes necessary because an improper installation of a backwater valve could push the backflow into a neighboring basement that did not previously was not subject to backflow.  I reckon there could be instances where residents have installed backwater valves without obtaining a necessary permit; after all, enforcement resources are not unlimited.   Sometimes people blame their local municipality for their basement and residential flooding problems and this is often without a sound and sufficient reasoning.

Other Backwater Valve Considerations

In some instances, basement floor drains may be connected to the municipal stormwater collection system.  This isn’t kosher, within the context of the Clean Water Act and the NPDES Phase 2 Storm Water Program; the basement floor drains should be connected to the municipal sanitary sewer collection system.

The backwater valve is imperfect.  Its prudent to consider avoiding buying a home that is located on a lower level than other homes on a sloping street.  Basements can be versatile additions to a residential property, particularly in north and northeastern parts of the country.  A basement can have multipurpose utility, however, installing drains in a basement may lead to complicated conditions, in some cases.  Its a bit unlikely that you will hear this from your real estate agent.  It would also be fair to expect that location and properties that are prone to flooding due to a gravity challenged location might be subject to higher home insurance rates.  Further, it would be reasonable to expect that properties that have resulted in multiple requests for reimbursements for flooding damage are likely to be flagged.

Does your home need a Backwater Valve? Source: Town of Las Gatos, California