Boman & Kemp has been producing galvanized area wells for over 50 years.
In the year 2000 we received our first report of a galvanized area well that was showing signs of corrosion.
Over the next several years we had multiple reports of premature window well corrosion.
This problem was occurring primarily in the Colorado and Utah markets.
We dug up a number of these area wells and replaced them with new area wells, and to our surprise the replacement area wells also rusted out in a short amount of time.
Over the next few years we spent a substantial amount of time and money looking for the cause of the problem.
Our analysis included studying all of the materials and processes involved in producing our galvanized area wells.
We found that the materials and manufacturing processes we had used successfully for decades were not at fault.
In the meantime we continue to stand behind our product while looking for answers.
In 2005 we hired the services of Qual Corr Engineering, a consulting company specializing in detection, diagnosis and prevention of corrosion.
Qual Corr’s research found that the failed area wells experienced corrosion because a corrosion cell had been created.
A corrosion cell occurred because a low resistance path between the area well and the rebar was introduced through the anchoring hardware.
Four components are necessary for a corrosion cell to occur:
An Anode, a Cathode, an Electrolyte and a Metallic Path connecting the anode to the cathode.
When these four components are present, and with the right soil conditions, rapid corrosion can occur.
In our situation, the Window Well is the Anode, the rebar is the Cathode, and the soil is the Electrolyte.
A Metallic Path is created when the area well comes in contact with the rebar, either through rebar touching a metal buck, or on wall mount area wells when an attachment bolt comes in contact with rebar during the installation process.
If the attachment bolt or Buck are touching the rebar, a Metallic Path is established.
If there is no Metallic Path, the circuit is not completed, and a corrosion cell will not form.
Therefore, the best way to prevent a corrosion cell from forming is to ensure the Buck and the attachment bolts do not come in contact with the rebar in the foundation.
Since you can’t see under the concrete, the only way to know definitively that a corrosion cell has not been formed is by testing.
There are two developments in home construction that have increased the chances of corrosion cells forming.
First, new structural engineering requirements, which have substantially increased the amount of rebar used in new home construction.
More rebar means more chances of inadvertently connecting the area well to the rebar.
Second, Ufer ground – the introduction to the Electrical Code of the use of Ufer ground which grounds the electrical system to the rebar in the foundation.
The Ufer ground and network of rebar function as an electrical conductor.
These changes in home building practices have an impact individually and together.
Qual Corr’s research helped us to identify exactly what was causing the Window Well’s to corrode.
Their subsequent recommendations are based on standards set by the National Association of Corrosion Engineers.
In summary, there are two things to do to help avoid the creation of a corrosion cell, when installing an area well.
Number one: position rebar around a window in a way that the rebar won’t make contact with the buck or the mounting bolts.
With the considerable amount of rebar going into the foundation, this requires a little planning and inspection before the foundation is poured.
If the buck or the attachment bolts end up touching the rebar, there is a high probability that a corrosion cell will be created.
And number two, conduct proper testing before and during the installation process to make certain that the buck, attachment bolts and area well are not in contact with the rebar.
The great value of testing is that you will know, as you are doing the installation, if you have errantly connected to the rebar, and you can easily fix the problem right then.
The further you advance in the installation process without testing, the greater your risk and expense for fixing the problem.
Testing protects your investment of time and materials.
The two methods of area well installation are Buck Mount and Wall Mount.
Since you will be doing testing with both methods, we will explain testing first, then walk you through the steps of buck mount and wall mount installations.
The test you will be conducting is referred to as a “Continuity Test.”
Continuity Test’s are used in electronics or electrical circuits to verify that current flows effectively through its intended path.
For example, if we test this wire with a Multimeter, it shows that there is a continuous flow of current through the wire.
However, if there is a break in the wire, the metallic path is separated and there is no continuity.
In our situation we will use a continuity test to make sure the area well is not connected to the grounding system, specifically the rebar and the foundation.
Knowing that the area well is not connected will give you confidence that the installation was done properly.
Tools you will need for continuity testing:
Digital Voltmeter, also known as a Multimeter, and a Copper Sulfate Electrode.
Steps for Buck Mount Installation:
1. Take your first reading from the Ufer ground.
Locate the Ufer ground. The Ufer ground is typically 18 to 24 inches long and usually located around the garage. Set the Voltmeter to 0.20 DC volts. Remove the electrode protective cap and press the pointed tip into the soil. Moist soil will give you the most accurate reading, so if the soil is dry don’t hesitate to add some water. Take a Voltmeter reading from the Ufer ground and write down the readings. This becomes part of the baseline for the rest of the testing. A typical Ufer ground reading will be between negative 0.11 and negative 0.25. For the home shown in this video the Ufer ground read negative 0.18. This is normal.
2. Test the Window Buck.
Scratch through the finish with the red lead and take a reading of the Buck. On this home the continuity test on the Buck read negative 0.61, a 0.43 volt spread. If you do not achieve a point to 0.20 or greater spread, it is an indication that a metallic bond was created and the buck is hot. Corrective measures would need to be taken. But since the buck read negative 0.61 and is not hot, Buck mount installation can proceed.
3. Mount the area Well.
Back out the top two bolts in the window Buck and remove the rest of the bolts. If the grade requires the area Well to be installed 12 inches or more above the Buck, the top of the area Well will need to be secured to the wall with additional concrete attachment bolts. Be sure to do a continuity test on each bolt used outside of the Buck.
Hang the area Well on the top two bolts, install the rest of the bolts with washers, then remove the top two bolts and install washers.
The installation is complete when the area Well is fully installed and the Buck attachment bolts and area Well have been tested and show that there is no connection or Metallic Path to the rebar.
Wall-mount Area Well procedures:
Identify the size of the area Well being installed and determine the centerline measurement from the table we provide.
For example, if the window is 4 feet wide, the table specifies spacing of 57 inches.
Mark the top of the area Well.
Bsed on the grade, determine the height the area Well will be positioned on the window opening and mark where the top of the area Well will sit.
Make vertical lines for drilling.
Draw two vertical lines 57 inches apart.
The numbers recommended in the table are important to follow so that a Safety Grate fits properly.
The area Wells are produced at the right specifications, but have a tendency to relax and spread when handled and stacked for transportation.
Using the centerline measurements will assure you of a proper look and exact fit for the Safety Grate and the Lexan Plastic Safety Great Cover.
Mark where to drill the top 2 holes.
Make a line 2 inches down from the marks showing the top of the area Well.
This is where you will drill the holes for the top 2 attachment bolts.
Drill and install the top 2 attachment bolts.
Hang the area Well and test for continuity.
Hang the area Well on the top 2 bolts and put on large washers and nuts.
Test the area Well for continuity.
In this example, the Ufer ground read negative 0.15 and the area Well read negative 0.91.
This shows that the attachment bolts, and therefore the area Well, are not in contact with the rebar.
Place the rest of the attachment bolts.
Push the flange in or out to align the key holes with the vertical lines, then drill and install an attachment bolt in each side using the appropriate washers.
Finally, test the area Well for continuity.
An important note: These numbers apply to testing the area Well during installation and prior to backfill.
Repeat the process.
We recommend placing the attachment bolts no more than 10 inches apart.
Continue until the area Well is secured to the wall.
The galvanization on our area Wells is sufficient to protect the area Well for many years, provided that it’s not part of a corrosion cell.
We have observed in a few circumstances corrosion cells being created with other metal structures coming in contact with an area Well.
One recent example was the metal lathe used to secure mortar for a veneer stone installation.
This should be avoided.
Our products are designed to have a long, useful life.
When installed properly, and verified by testing, we warrant our area wells for 10 years.