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Dear Leo:
Enclosed is the payment for the radon mitigation you performed at our home.
Thank you so much for the professional job. We would not hesitate to recommend your company to anyone with a radon problem.

Thanks again,

Margaret P.

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Learn more about the founder of Radon Home Measurement & Mitigation
Learn more about the founder and President of R.H.M.M.
Dr. Leo Moorman Ph.D.

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Example of five different systems installed by us to solve radon problems:

These are examples as every house is different and an optimal solution can be found depending on the many details of your house. The first three examples are also called Active Soil De-pressurization (ASD) systems and are based on the principle that the radon is captured under a radon barrier -- The barrier consists of the concrete basement slab that is hermetically sealed, or an impermeable barrier to be installed in a crawlspace -- and guided via a vent pipe to above the roof line using an active element in the form of a powerful, yet low noise in-line ventilator. The fourth example is based on an entirely different principle as explained. The fifth example shows how a crawlspace looks after the radon barrier is installed.

1: Interior Radon Mitigation System
In the case of an Interior System the pipe can be shielded from the outside view and noise can be kept away from interior finished areas.
radon system in atticIn the first picture the ventilator is in the attic of this home. The vent pipe is here only visible as a small speck on the roof. The pipe routing went from unfinished basement into the kitchen pantry (backside wall) into the master bedroom closet (along backside wall) into the attic and through the wood shake roof. The ventilator was placed in the attic immediately under the roof as shown in the next picture.

Interior System: Ventilator and pipe optimally shielded from the view, outside and inside.

Or the pipe can vent hidden through back side of garage roof

Example how the ventilator can be placed in the attic of the home.

2: Exterior Radon Mitigation System

Exterior Radon System An Exterior Radon Mitigation System has the ventilator on the outside of the home, preferably out of view from street side and back sitting area because of visual and noise concerns. These systems are not less effective in removing the radon than interior systems but often allow a more cost effective approach at the cost of the visual and noise impact of the system on the outside of the house.

Exterior System: More visible from the outside and somewhat more noisy than an interior system

3: Super-Low-Noise Exterior Radon Mitigation System

Low Noise Radon Mitigation System
Click photo to see more pictures of a Super Low Noise radon mitigation system.

This system was developed by us for one of our customers. The noise that the conventional exterior system (see example 2 above) made bothered her next to the sitting area on the deck. The conventional exterior system was inherited from the seller in the real estate transaction. The current home owner requested to transform the system in a radon mitigation system that gives the lowest-noise-possible. This became our "Super-Low-Noise" option.

Super Low Noise Exterior System: Minimizes noise in case the system has to be placed outside near a deck or sitting area.

4: Energy Recovery and Ventilation Radon Mitigation System

Low Noise Radon Mitigation System
Energy Recovery & Ventilation System

In the case of an Energy Recovery and Ventilation systems the principle of the mitigation is different from the conventional systems discussed above: A dilution of radon concentration is caused by constantly bringing in fresh air and removing stale air from basement or whole house. This is a good option if the building also benefits from fresh air circulation, such as in older buildings, buildings with odors in basement, or inaccessibly low crawlspaces ("engineered", suspended wood floors in basements, with a crawlspace equal or less than 2 feet high). Another example is when the basement or area is used as office and there are not a lot of windows and the area can use fresh air summer and winter.

5: Crawlspace Radon Removal System

Crawl space radon mitigation system
Click photo to see more pictures before and  after radon mitigation .

In the case of a 4 foot high crawlspace in your home a conventional radon mitigation system (ASD) is installed (any one of the examples 1 through 3) in combination with a collector system under this white special radon barrier (black plastic is not a radon barrier) as is shown in various pictures.

In the case of a 4 foot high crawlspace in your home a conventional radon mitigation system (ASD) is installed (any one of the examples 1 through 3) in combination with a collector system under this white special radon barrier (black plastic is not a radon barrier) as is shown in various pictures (click photo for more pictures).

Radon Mitigation

Why use RHMM for your radon mitigation needs:

A fully certified person by the National Environmental Health Association (NEHA) will do the Radon Mitigation.
EPA standards and procedures will be followed.
We have mitigated all types of homes including:

  • Two story homes with finished and unfinished basements.
  • Ranch with full finished and unfinished basements, and crawlspace.
  • Tri-level homes with partial crawlspace.
  • New and Old homes.
  • Businesses and commercial properties

Typically we obtain results below 1.5 pCi/L after our mitigation is done.
We work professionally and clean. After the mitigation work is over, apart from a system that is installed appropriately hidden in your home, there is hardly any tell tale signal that we worked in your home.
Our systems are always designed to incorporate your wants and needs in them:

  • We will find the best solution
  • We will find a solution with the least visible changes to your home, so you do not have to worry
    about loss of value and extra stress when reselling your home.
  • Sometimes we will be able to propose a very economical solution depending on the special
    configuration of your home. This is why we want to personally visit your home to inspect
    whether there are such possibilities that are still consistent with the EPA-standards.

Here we show some of the special tools needed to install a radon mitigation system:

Shown to the left is a water cooled and flushed diamond core drill to core holes of appreciable size. The water flushing minimizes the generation of dust in your house and helps cool the drill.

Cores drilled from concrete basement slabs with the diamond core drill:

Most concrete slabs are four inches thick, but there are exceptions as shown here


When we have finished preparing the hole for radon mitigation and the sub slab de-pressurization communication test a large diameter PVC pipe is attached via a perfect match to the hole with the appropriate bushing to prevent air leakage around the edges. This makes the system low noise and gives it the look as if the system was built-in during the original construction of the building. In this picture it can also be recognized how all reachable expansion joints, cracks and grooves in the entire basement are caulked with a liberal amount of caulk following the EPA recommendations.

Depending on the location of the fan, sometimes a vertical pipe section will have to be visible in a garage. It is kept close to the wall and placed where it is hardly noticeable:


Guaranteed low radon result after mitigation using the SSDC-tests.
Special methods and instruments during the job help us to ensure a guaranteed low radon concentration in the end. As and example we show here a special highly sensitive pressure manometer to perform sub-slab de-pressurization communication (SSDC) tests to be able to tell the home owner whether the ventilator system reaches under the entire slab or only a part of it. As shown in these pictures these tests can be done as soon as the radon extraction hole is drilled with our core drill and is prepared for the radon mitigation by using the same in-line ventilator that is eventually used for the radon mitigation. Some companies use a vacuum cleaner to create the suction power for this test, but a vacuum cleaner has different characteristics than this ventilator therefore the result with a vacuum cleaner is not always reliable. Our test using the ventilator that will be installed has been shown to be reliable indicator.

The appropriate ventilator is placed in the bushing for the SSDC-tests:
This sensitive manometer test is part of the SSDC-test that can indicate during the day of installation whether the house will be mitigated below the action level.

As an added benefit this allows us to make adjustments to optimize the system during installation if doubts exist.
In the example shown the level came out low after performing the EPA 48-hour radon test: The house was mitigated from an original level of 15.5 to 1.4 pCi/L

Traveling the distance to your home
Most mitigations can be done in 1 or 2 days. We are completely ready to travel a distance. With a Cargo Van and Trailer we can handle tools and materials for almost any radon job within reasonable distance. This allows you to get the radon expertise you need to solve your radon problem right at your home. We are also committed to communicate with you by e-mail or phone about any questions you might have about the mitigation system after the installation was completed.

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