Square One Radon, LLC logo
Approved Pro
This pro has maintained an average of 4.5+ star throughout their time with Angi.
Approved Pro

Square One Radon, LLC

Radon Gas Testing, Radon Gas Abatement,
This pro has maintained an average of 4.5+ star throughout their time with Angi.

About us

Square One Radon is the premier choice for radon measurement and mitigation on all projects small and large, old and new. Owner and founder, Rob Hartop, brings over 12 years of radon industry experience along with a multitude of credentials including NRPP specialty certifications for new construction, multifamily, and advanced mitigation techniques. We are licensed in the State of Colorado, and are fully insured, certified, and bonded. We can mitigate any home or building, and will give you a free quote right away. Ask about our industry-leading guarantee!

Business highlights

Se habla espanol
5 years of experience

Services we offer

Active Member, American Association of Radon Scientists and Technologists, Crawlspace Encapsulation , NRPP Advanced certifications for new construction and multi-family projects. , Radon Gas Testing and Mitigation, Radon design and build services for new construction (RRNC, IRC Appendix F, ASTM, ANSI)

Amenities

Free Estimates

Yes

Warranties

Yes

Accepted Payment Methods

  • CreditCard
Reviews
5.038 Reviews
Number of StarsImage of DistributionNumber of Ratings
5
100%
4
0%
3
0%
2
0%
1
0%

Filter reviews by service

Showing 1-25 of 38 reviews
Darcy B.
Sep 2025
5.0
Radon Gas Abatement
$3,074
Rob & his team were professional, friendly, respectful, neat, informative, communicative & did a great job! Fantastic crew & my radon level is way down. I could actually smell a difference in my home as soon as the work was completed, which only took one day in my 1700 sq ft house. 10 Stars to Square One!!!

Patrick R.
Aug 2025
5.0
Radon Gas Abatement
$2,998
The quote for the abatement was fair and the job was done within 10 days. Rob answered any questions as did the workers when they were performing the abatement work. The crew showed up on time, worked diligently without any bother to me, were polite and cleaned up totally after the job was completed. Recommended!

Marni F.
Jul 2025
5.0
Radon Gas Abatement
$1,800
They were fantastic to work with from start to finish! Highly recommend.

Cherlyn C.
Jun 2025
5.0
Radon Gas Abatement
$3,929
Rob's remediation plan was clear and dealt with two crawl spaces simultaneously with one fan. The other contractor's we got estimates from were looking at two systems. His laborers were friendly and competent. They also cleaned up after themselves at the end of the first day even though they were coming to finish the job the next day. Nice clean up at the end of the job.

Brad B.
Mar 2025
5.0
Radon Gas Abatement
Rob and his crew showed up on time and went right to work on my crawlspace. They cleaned it up and installed all of the radon mitigation equipment in 2 days. THANKS AGAIN ROB

John T.
Mar 2025
5.0
Radon Gas Abatement
$3,900
They did exactly what they described. They worked with my preferences for motor placement and vent location. They were VERY polite and respectful. I recommend them without reservation.

Tim Z.
Mar 2025
5.0
Radon Gas Abatement
Rob Hartop owner of Square One LLC was very professional, knowlegable and his crew was very efficient. Our installation project took less than 4 hours! We interviewed 4 Radon Mitigation companies and Square One hands down were the most experienced and also affordable! Great to do business with a reputable company. . . Thank you!

Tim Z.
Mar 2025
5.0
Radon Gas Testing
$1,629
Rob the owner of Square One Radon LLC is very professional, courteous and kind. His company is very experienced and trustworthy. Our mitigation projece was finished in a efficient manner and y

Ariana B.
Nov 2024
5.0
Radon Gas Abatement
Yes, I recommend this pro
$3,582
Very professional, honest, fast and efficient. Would recommend this company to anyone.

Ron D.
Jul 2024
5.0
Radon Gas Abatement
Yes, I recommend this pro
$3,500
Very professional, answered/explained questions asked, very knowledgeable, prompt with app'ts, polite and courteous and overall a pleasure to do business with. Highly recommend company as a skilled service provider.

Sarah M.
Jul 2024
5.0
Radon Gas Abatement
Yes, I recommend this pro
$3,138
I definitely recommend this company. They were on time, friendly, professional, and the owner even killed some wasps for me which was a lovely added bonus. The price was comparable to other quotes I received so felt quite reasonable. Their work comes with a warranty as well and the owner explained everything in a way that it was easy to understand.

Steve B.
Jul 2024
5.0
Radon Gas Abatement
Yes, I recommend this pro
$2,370
Rob was a good communicator. He gave me options on how I could mitigate radon in a house we purchased. Together, we came up with a solution, and his crew of 4 did the job professionally in one day as requested. Highly recommended.

Kimberley F.
May 2024
5.0
Radon Gas Abatement
Yes, I recommend this pro
$3,100
Great communication from the get go. Inquiry was answered promptly, testing was explained. Mitigation options were thoroughly explained, scheduled and completed in a timely and professional way. Showed up on time, easy to have on the premises/property and picked up after themselves, very very pleased and would highly recommend this team of professionals.

Dan P.
Apr 2024
5.0
Radon Gas Abatement
Yes, I recommend this pro
Square One Radon did a great job. Friendly and professional. Our radon level went from a 5.5 to .5. We feel safer in our home.

Joe H.
Apr 2024
5.0
Yes, I recommend this pro
$7,100
Square One Radon is one of the most professional, technically competent companies I've dealt with. Customer service is in the forefront of their business operations. Rob confirmed the high radon gas levels which were established by an independent testing laboratory, devised a plan on how to correct the issue and meet national EPA standards, thereby eliminating the threat they posed. The cost proposal was very detailed, including options, if needed. Work was performed exactly when and as agreed, the crew was very sensitive to keeping our home clean, and was completed when Rob stated it would be done. Communication throughout the project was excellent. As a former Director of Contracting for the Air Force, I can say that Rob is excellent to work with, his proposal was clearly stated, and the results of the work by Rob and his excellent crew resulted in radon levels being reduced from a reading of 800 in the crawl space, 116 inside our home, to a level of 0.2 pico curies per liter post project. You will not be disappointed! Highly recommended!

Sandra P.
Mar 2024
5.0
Radon Gas Abatement
Yes, I recommend this pro
They were right here to help us get it done!

Robert M.
Aug 2023
5.0
Radon Gas Abatement
Yes, I recommend this pro
$3,800
Sq-One is an excellent resource for radon mitigation. They came and looked the project over, provided a realistic estimate, did the work at the time they scheduled, got it done efficiently, cleaned up thoroughly and left the house in the shape it was when they arrived. The bill was exactly as was estimated. Bob McHugh - Realtor

Mary C.
Jun 2023
5.0
Radon Gas Abatement
Yes, I recommend this pro
They were great and professional. Thsnk you.

Tyler H.
Apr 2023
5.0
Radon Gas Abatement
Yes, I recommend this pro
$3,030
Rob and his crew were awesome. They started out by covering my floor and I knew it was going to be a great experience. Rob was very knowledgeable and help me make a decision on where to put the radon fan and pipe to best suit my needs. The installers were clean, kind, and did an awesome job. The other bid I got was going to cut corners and not do the job to code. I am so glad tht I went with Square One!

Richard T.
Mar 2023
5.0
Radon Gas Abatement
Yes, I recommend this pro
Rob and Square One were quick, efficient, and great to work with. Highly recommended.

Orvid M.
Feb 2023
5.0
Radon Gas Testing
Yes, I recommend this pro
$1,400
The crew was very timely and knowledgeable about the job. Easy to explain the process..comfortable to work with. I was very happy with the work.

Christi W.
Nov 2022
5.0
Radon Gas Abatement
Yes, I recommend this pro
We had one afternoonbetween my mother closing on her house and moving in. Not only was Rob’s bid the most thorough, professional and easy-to-understand bid that we received, he went out of his way to make our schedule work. Rob did excellent work, arrived when he said and answered all of our questions — and he was nice to work with. We would highly recommend Square One Radon and know that our someday buyers will be reassured, too!

Allen S.
Nov 2022
5.0
Radon Gas Abatement
Yes, I recommend this pro
They are very friendly did a good job cleaned up very nicely when they were done

Andrew M.
Nov 2022
5.0
Radon Gas Abatement
Yes, I recommend this pro
$1,446
Highly Recommended - Square One Radon provides exceptional radon mitigation products and services. Rob is an extremely customer focused, highly knowledgeable, seasoned professional. After buying an Airthings Wave Smart Radon Detector, I discovered our home had consistently high readings, well over the federal guideline of 4.0. Like everyone else, I did an internet search and read reviews to locate someone that performs radon mitigation services in the Grand Valley. Rob reviews were spot on - this guy knows his stuff, installed quality components, at a very reasonable price, and provided an exceptional lifetime radon level guarantee. End result, after the install was complete, which took the team less that 4 hours, radon levels in our house dropped like a rock - significantly below the federal guideline levels. Again, do not hesitate to hire Rob, you will be glad you did.

Rhiannon S.
Jul 2022
5.0
Radon Gas Abatement
Yes, I recommend this pro
$1,429
Highly recommend for radon mitigation needs! Rob got back with me immediately from the initial contact all the way through to completion, to answer any questions, and explain the process. He is friendly, professional and most importantly completed the work as quoted and his system got our radon level from approximately 7 to 0.6. Look no further if you need radon mitigation!
Showing 1-25 of 38

Licensing

Licensed*

Trade License Number

RME.0000007

Trade License Locale

CO

Trade License Expiration

05/31/2026

State Contractor License Requirements

All statements concerning insurance, licenses, and bonds are informational only, and are self-reported. Since insurance, licenses and bonds can expire and can be cancelled, homeowners should always check such information for themselves. To find more licensing information for your state, visit our Find Licensing Requirements page.

*Contact business to see additional licenses.

FAQ

Square One Radon, LLC is currently rated 5.0 overall out of 5.

Monday: Open All Day Tuesday: Open All Day Wednesday: Open All Day Thursday: Open All Day Friday: Open All Day Saturday: Open All Day Sunday: Open All Day

Square One Radon, LLC accepts the following forms of payment: CreditCard

Yes, Square One Radon, LLC offers free project estimates.

No, Square One Radon, LLC does not offer eco-friendly accreditations.

No, Square One Radon, LLC does not offer a senior discount.

No, Square One Radon, LLC does not offer emergency services.

Yes, Square One Radon, LLC offers warranties.