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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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Examples of radon mitigation systems installed by R.H.M.M.

These are radon mitigation system examples installed over an extended period by RHMM, with original radon concentrations reported to us shown in the column with header "Before", and a clearance test done by us after mitigation based on a short term (2 day) tests that follow EPA guidelines. The purpose of the clearance test is to present the completed radon mitigation system to the home owner so they can also perform  their own post mitigation radon test to proof that the system is working. Since we are an NRPP certified radon testing company it is our policy to write a full EPA test report to the customer of our post mitigation test. This procedure is consistent with  the EPA protocol. 
  

System types:

In the column with header "Building Type" we indicate whether the house is a one-story ranch, bi-level, tri-level etc. Tri-level homes have variations where the lowest and middle floors consists of either a concrete slab plus a crawlspace (Slab +Crawl), or of two slabs. We also show if basements are finished or unfinished where relevant. Some additional remarks can be found on special situations we encountered.
In some cases we go through 3 finished levels vertically up plus an attic, this is indicated as "3.5 levels".

Under the header "System Details"  we distinguish when the system was Interior (fan in attic) versus Exterior (fan outside). Here we also show the number of branches that were installed on that system.

Finally under "System Type" we indicate whether the system reaches the entire footprint with the vacuum produced by the ventilator (also called the Pressure Field Extension, or PFE) as verified by the sub-slab de-pressurization communication (SSDC) test on the day we do the work. This completes with the caulking of all reachable areas an EPA system. Therefore this is called  a "Complete System". If a small section of additional slab, or crawlspace exists that is not reached with the vacuum, such a system is called an Incomplete, or Phase I system. Incomplete systems are only installed if they have shown to work via the Clearance Test, and perpetual continued testing by the home owner is encouraged to test if they continue to work.  

"Ideal Systems" are systems that have unfinished basements and all cracks, grooves and openings can be completely caulked and they have a an interior drain tile pipe on inside of the footer that can be reached. This is the same as an RRNC-system in new home construction. In addition we can step up the quality of a regular  RRNC to take better care of energy losses by installing a double barrier under the concrete slab which are individually fully sealed to the foundation and footers in new home construction. The latter is called an "Ideal System" with additional energy efficiency features. These systems are recommended when the slab has in-floor heating. 


The color designation in the background of each row is emphasizing the following characteristics of system and home styles:
  
Existing <3 Br.
            Green = Existing homes with radon system that have 1 or 2 Branches. 
>2 Branches
             Red = More complicated systems and/or with 3 or more Branches.
Ideal Systems
              Purple =  Ideal Systems.
Alternative
               Blue = Alternative Systems.   
Activation
                 Yellow = Passive to Active system conversion.

List with examples of mitigated homes by RHMM:
Street Name Before After Building Type System Details System Type
pCi/L pCi/L
1 Westview Ave 53 0.9 2 story, finished basement+Crawl Interior 3 Branch Complete System
2 Candeleria 6.9 1.2 2 story with basement Interior 1 Branch Complete System
3 Shelby Dr. 5 tbd Passive to Active conversion 2.5 stories Complete System
4 Sedgewick Dr. 20 1.2 Ranch Interior,
2 Branch
Complete System
5 N. Kennedy Ave. 4.7 0.5 tri-level Interior,
3 Branch
Complete
system
6 Southern Cross Lane 4.5 1.7 Passive to active Conversion 2.5 stories Complete system
7 Bianco Dr. 8 1.7 Ranch, with  Basement Interior
1 Branch
Complete System
8 Eastborough Dr. 9 0.6 Bi-level Interior,
1 Branch
Complete System
9 Montmorency St. 3.9 1.0 Ranch Interior,
1 Branch
Ideal System
10 Berkshire Dr. 13.3 1.2  tri-level  w. 2 Slabs  Interior,
2 Branch
Complete System
11 Independence Rd. 9.4 tbd Bsmnt + Crawl  Interior,
2 Branch
Complete System
12 Loyolla Avenue 10 0.0 Ranch over Crawl  Interior,
1 Branch
Ideal System
13 6th Place SW 13 1.1 Ranch, Fin. Bsmt.   Interior,  1 Branch Complete System
14 Santa Fe Ct. 8 2.1 Ranch, Unfin. Bsmt.  Interior , 1 Branch Complete System
15 Hollyhock St. 5 1.6 Ranch, Fin. Bsmt  Interior, 2 Branch Complete System
16 Pearl Creek Dr. 35 2.8 2 Story over Crawl  Exterior, 1 Branch Incomplete Syst.
17 Stanley Circle 5.8 1.3 Ranch, Fin.Bsmnt+Crawl  Interior, 2 Branch Complete System
18 N. Overland Trail N/A tbd Solved noise issue System  originally installed by others.  Exterior, 1 Branch Incomplete System
19 Meadow View Pwy 17 2.5 2 Story over Unfin. Bsmnt with wood structural floor  Interior
1 Branch, 3.5 levels
Complete System
20 Bayside Circle 9.3 1.5 Town home over Fin. Bsmnt.  Interior
1 Branch, 3.5 levels
Complete System
21 Shadow Mntn Dr. 9.6 1.0 Tri-level w. two slabs Exterior, 2 Branch Complete System
22 Copernicus Dr. 1.1 Passive to Active Conversion Interior, 1 Branch Complete System
23 White Pines Dr. 9.6 0.4 Ranch over Crawl Interior, 1 Branch Ideal System
24 Picadilly Dr. N/A tbd Fin. Bsmnt+ Crawl Interior, 2 Branch Complete System
25 Rangeview Dr. 12.7 1.7 Unfin. Bsmnt. Interior, 1 Branch Complete System
26 McClellan St. 13 1.3 Unfin. Bsmnt + Crawl Interior, 2 Branch Complete System
27 Animas Place 12.6 1.2 Fin+Unfin+Crawl(2x) Interior, 5 Branch Complete System
28 Shelburne Ct. 9 1.9 Fin. Bsmnt + Crawl Interior, 2 Branch Complete System
29

Prairy Ridge Dr. 12 1.9
Fin. Bsmnt + Crawl Interior, 2 Branch Complete System
30 Phoenix Dr.      ? 1.6 Fin. Bsmnt +Cawl Interior, 2 Branch Complete System
31 Parkhill Ct. 9 0.9 Fin + Unfin. Bsmnt Interior, 1 Branch Complete System
32 Newcastle Dr.  6.6 1 Fin. Basmnt Interior, 1 Branch Complete System
33 DesMoines Dr. 5.8 1.6 Unfin. Bsmnt Interior, 1 Branch Complete System
34
Annelise Way   ? 0.7 Passive to Active Conversion Interior, 1 Branch Complete System
35 CR 23 29.2 0.5 Unfin. Bsmnt Exterior, 1 Branch Complete System
36 37 St. 12 0.7 2x Crawl. Interior, 1 Branch Ideal System
37
Parkhill Ct. 9.3 1.4 Passive to Active Conversion 1 Branch Complete System
38
Jackson Ave. 9.7 0.5 Ranch on Grade Interior, 6 Branch Complete System
39 Sand Dollar Dr. 9 1.7 Unfin. Bsmnt. Passive to Active, 1 Branch Complete System
40 Guardian Peak Dr. 8.5 3.8 Fin. Bsmnt + Crawl Exterior, 3 Branch Complete System
41
Langdale Dr. 27 2.2 Fin. Bsmnt Exterior, 1 Branch Complete System
42 Golf View Way 12 0.9 Fin Bsmnt 2 x Exterior, 5 Branch Complete System
43 N. Sheridan Ave. 13.9 0.4 Bsmnt + Crawl Exterior, 2 Branch Complete System
44
Blackwood Dr. 13 2.1 Unfin Bsmnt Interior, 1 Branch Complete System
45
Eric St. 8.3 0.9 Ranch on Grade Interior, 1 Branch Complete System
46 Iowa Ave. 24.3 1.0 Fin+ Unfin. Bsmnt Interior, 3 Branch Complete System
47 Rossum Dr. 16.2 0.7 Fin Bsmnt Passive to Active Complete System
48
Onyx Place     ? 1.5 Unfin Bsmnt Interior, 1 Branch Complete System
49 Crestview Dr.      ? 1.2 Unfin Bsmnt Interior, 1 Branch Complete System
50
Ridgeway Dr. 15.2 1.0 Fin+unfin Bsmnt Interior, 2 Branch Complete System
51 Lindenview Ct. 4.9 1.2 Fin Bsmnt Interior,
2 Branch
Complete System
52 Monaco Pl. 7.9 2.1 Fin. Bsmnt Exterior, 1 Branch Complete System
53 Mohawk St. 13 1.6 Fin. Bsmnt Interior,
3 Branch
Complete System
54 Cottonwood Circ 14.5 0.7 Fin. Bsmnt 2 x Interior,
3 Branch
Complete System
55
Stuart St. 19.5 2.0 Fin. Bsmnt Interior,
2 Branch
Complete System
56
Grand Canyon St. 4.2 1.6 Fin Bsmnt + Crawl Exterior, 2 Branch Complete System
57
Rollingwood Lane 11.2 0.9 Fin + 4 x Crawl Exterior SLN,
5 Branch
Complete System
58 Fish Creek N/A RRNC +
Low ENERGY Loss
Interior,
1 Branch
Ideal Energy Eff.
59
McGraw Rnch Rd N/A tbd RRNC + Heated Slab+Crawl
Low ENERGY Loss
Interior,
2 Branch
Ideal Energy Eff.
60
Animas Place 29 2.8 Fin + Unfin. Bsmnt Interior,
4 Branch
Complete System
61 Critter Ct.     ? 0.5 Crawl Interior,
1 Branch
Ideal System
62
Kiva 7.8 2.0 Ceremonial House + Tunnel + Tower ERV ERV
63
Alta Vista Dr. 7.8 1.3 Unfin Bsmnt +   Exterior, 2 Branch Complete System
64
Preserve Dr. N/A RRNC Interior,
1 Branch
Ideal System
65
Taft Hill Dr. 8 Ranch with wood lifted floor + Crawl Interior, 2 Branch Complete System
66
Miwok 175 Unfin. Interior,
1 Branch
Complete System
67 660 3.5 Ranch with Finished Bsmnt Exterior SLN,
2 Branch
Complete System




Radon Concentration distribution BEFORE radon mitigation systems were installed

The hystogram below of data from before 2001, shows that roughly three out of four homes that were not tested for radon can expect to have a radon concentration larger than the EPA level in the lowest lived in area in our local region near Fort Collins CO. 

Radon Concentration distribution in homes before radon mitigation.


Radon Concentration distribution measured AFTER radon mitigation was completed.
An artists rendering based on the real data that we had measured after radon mitigation was completed shows a frequency distribution strongly peaked under 2.0 pCi/L, but that we cannot exclude finding radon levels up to 4 pCi/L occasionally. This can be understood if we take all sources of radon into account that are not only from below the slab, but also from above the slab, and also sources that have to do with variability of the weather and connections to the soil cavities are taken into account. Colorado has Karst and Karst like areas that contribute to the latter resulting effect. What also contributes is that a long term (one year long) test may show lower radon presence in the house due to the open conditions that exists during part of the time as opposed to all short term tests below, that were done within a few days after the mitigation in a two-day test period with closed house conditions that followed EPA guidelines.   Therefore the post-mitigation testing distribution may be somewhat skewed towards the higher values. However these are the values that were measured.  All systems were quality systems.  Phase 1 (incomplte) systems that had original values at or over 4.0 pCi/L  were always finished with Phase 2, causing them to have a level below 4.0 pCi/L, and in effect moving them into the "Complete System" category.

Distribution of final radon values.



Hourly distribution of radon concentrations as a function of time AFTER we installed a radon mitigation system in a home  with 57 pCi/L before the mitigation.

Post mitigiton CRM radon test of ome with hig original level


These are only 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 Depressurization (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 roofline 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 masterbedroom closet (along backside wall) into the attic and through the woodshake 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.

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

Radon mitigation system in crawl space
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

Low Noise Radon Mitigation System
Click photo to see more 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.

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.

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