If you are a contractor, builder or architect in Larimer County, CO, you are probably aware that the area has adopted the 2021 International Residential Code (IRC). This is a series of rules established by the International Code Council (ICC) to which all new residential building projects must adhere.

As of March 2022, several amendments were added to the overall IRC. And Larimer County has opted to adopt these amendments, as well. One of the big changes is that air barrier inspections are now required on new builds.

Building Envelope Performance Verification

The state of Colorado is constantly striving to increase statewide sustainability. That is why factoring in energy efficiency is a major part of the CO residential building process. It is no surprise then that many counties, including the Larimer County, have adopted the energy-related guidelines of the IRC. Chapter 11 of the IRC focuses on energy efficiency.

One of the primary amendments to this chapter now requires “building envelope performance verification.” This means that, before siding is added to a home, a certified inspector must examine and approve its exterior air barrier. Additionally, an air leakage test must be conducted on the home upon completion to make sure it meets energy efficiency requirements. The excerpt below highlights the key points in the amendment:

1. A review of the construction documents and other supporting data shall be conducted to assess compliance with the requirements in this section.

2. Inspection of continuous air barrier components and assemblies shall be conducted during construction while the air barrier is still accessible for inspection and repair to verify compliance with the requirements of this section and Table N1102.4.1.1.

3. An air barrier and air sealing inspection report shall be provided for inspections completed by the approved air leakage testing agency. The air barrier and air sealing inspection report shall be provided to the building owner or owner’s authorized agent and the code official at the time of the framing or insulation inspection. The report shall identify deficiencies found during the review of the construction documents and inspection and details of corrective measures taken.

As stated in the excerpt above, the construction docs will be reviewed by a qualified inspector. These building plans should meet the guidelines established in  the amended rules. Furthermore, the actual construction should follow the construction plans.

It is key to conduct the exterior inspection while the barrier can still be accessed. That way, if any deficiencies are noted, they can be adjusted or repaired efficiently. It would be a much more difficult task to make any air barrier changes after the exterior siding is installed!

A guide in the IRC (labeled as Table N1102.4.1.1) provides an in-depth breakdown of all components of the home, and how each of them should be configured in order to meet code requirements.

Meeting Air Barrier Code Requirements

When it comes to this code, the overall concept is simple – a continuous thermal envelope. or air barrier must be constructed around the house. Any breaks or joints in the air barrier material must be sealed by a code-approved material. Also, the insulation material used for the air barrier cannot be air permeable.

As mentioned above,  Table N1102.4.1.1 provides an extensive explanation regarding each component of the house. So if you want the nitty gritty details, go take a look a the table. But for the sake of this article, we will give you a brief overview:

• Ceilings/Attics – Inspectors will want any access points to unconditioned attics to be sealed with the proper air barrier materials. Additionally, any dropped ceilings or soffits should be outfitted with an air barrier that is aligned with the insulation.
• Walls – Any junctions from sill plate to foundation or top plate to exterior walls must be properly sealed. Additionally, if your attic has knee walls, they must be sealed.
• Windows/Skylights/Doors – All the framing of these penetrations needs to be properly sealed.
• Rim Joists – Exterior air barriers must extend over any rim joists.
• Floors – Any exposed edges of floor insulation must be reinforced by an air barrier. This also applies to cantilevered floors and floors above garages.
• Basements/Crawl Spaces/Slab Foundations – Exposed earth in unvented crawl spaces must be covered with the proper air or vapor barrier. Penetrations in foundation walls and slabs need to be sealed properly.
• Shafts/Penetrations – Ducts, shafts, or penetrations to the exterior or unconditioned spaces must be sealed with approved materials.
• Narrow Cavities – Any cavities too narrow to hold insulation need to be air sealed.
• Garage – Air sealing is needed between the garage and conditioned spaces.
• Recessed Lighting – Lighting fixtures present within the thermal envelope of the building must be properly air sealed.
• Wiring/Plumbing/Other Obstructions – Any breaks in the thermal envelope caused by wiring, plumbing etc. need to be sealed.
• Showers/Tubs – The air barrier installed adjacent to tubs or showers must separate the exterior wall from the tub/shower.
• Electrical or Phone Boxes – Air barriers must be installed under exterior electrical or phone boxes. Air sealed boxes can also be installed as an alternative.
• HVAC Register Boots – HVAC supply/return register boots that penetrate the thermal envelope need to be air sealed.
• Concealed Sprinklers – Concealed fire sprinklers must be sealed, where necessary, according to manufacturer’s recommended method.

Air Barrier Inspections

At Scott Home Inspection, we offer all the Energy Services you’ll need to make sure your building project is up to code. As a qualified third party inspection firm in Larimer County, we have a team of specialists that can inspect and document the exterior of the house to ensure that the building envelope is sufficiently configured.

Additionally, we are also certified to perform blower door, air leakage testing in Larimer County. Due to its adoption of the IECC Residential Energy Codes, Larimer County has required this type of testing in new builds for several years.

By conducting blower door tests, our energy specialists are able to not only determine the energy efficiency of the home, but also identify the sources of air leakage. That way you can make the necessary repairs, as needed, and continue to progress through your building process without a hitch.

We are proud to offer a whole list of specialized Energy Services to Larimer County. We have been providing the region with some of our milestone services such as blower door tests, insulation inspection, and duct leakage testing for years. And now we are ready to take on the newly mandated air barrier inspections with the same professionalism, expertise and efficiency.

If you are in need of an air barrier inspection (or any inspection service for that matter) for your building project, please don’t hesitate to reach out to Scott Home Inspection today! Click here for more info, or click here to schedule your service.

If you are a Colorado resident, you are likely aware of the dangerous, radioactive gas, radon. It is prevalent in many CO regions, and prolonged exposure to it can cause serious health issues. Radon mitigation systems are the best way to keep toxic levels of radon to a minimum in the residential setting. That’s why these systems have grown to be such an integral part of newly constructed CO homes.

The Environmental Protection Agency (EPA) compiled a map that illustrates the level of radon risk in every county of the United States. As you can see from the map below, almost all of Colorado is in Zone 1, which is the highest radon risk.

The ICC and Radon Mitigation

The International Code Council (ICC) established a guidebook of codes to which newly constructed homes must adhere. Most of the standards in the guidebook are required in all new homes. However, there are certain items mentioned in its appendix portion that are not actually required by the ICC.

One such section is the appendix about radon control methods, which states:

“This appendix contains requirements for new construction in jurisdictions where radon-resistant construction is required.”

Because levels of radon vary from region to region throughout the country, it isn’t always necessary to install mitigation systems. For instance, there are areas in the southern parts of the nation that are in Zone 3 with very low risk and no need for mitigation. Thus, the ICC leaves it up to the individual municipality to make the final call.

Radon Mitigation Code in Colorado

In Appendix AF Radon Control Methods, the ICC provides a list of CO counties that are at high risk for radon exposure – and there are a lot of them. Certain areas, such as Boulder County, Larimer County, and the City of Longmont are acting accordingly and making radon-resistant construction a must for new builds.

At the time of this writing, the policy has not been uniformly adopted throughout the whole state. However, homebuyers will often still opt for radon-resistant builds, due to the state’s high radon risk.

With Colorado building code becoming stricter and more energy/safety conscious, it would not be surprising to see the whole state make radon-resistant new construction mandatory in the near future.

Ok, let’s say your area does require radon-resistant construction measures to be taken. Or maybe it’s not required, but you’d still like to take the extra precaution and get a system installed. What steps do you need to take to make sure your new build fits the qualifications? Well let’s take a deeper dive into the ICC’s radon control requirements.

ICC Radon Reduction Requirements

1. A layer of gas-permeable material must be installed under the slab and all floor systems that are in direct contact with the ground and within the house foundation.
2. A soil-gas-retarder of approved material must be placed securely over the entire surface area of the aforementioned gas-permeable material.
3. Any openings or entry routes (i.e. floor openings, condensate drains, sump pits etc.) that could permit the flow of radon must be sealed properly.
4. Some type of passive radon mitigation system must be installed, depending on the configuration of the home.
5. The vent pipe must be accessible in the attic space or somewhere outside the habitable space in case fan installation is needed in the future.
6. Exposed interior portions of the radon mitigation piping must be labeled, in order to be properly identified.
7. A power source must be available in an anticipated location in the case that active fan installation is needed.

Once construction is complete and the structure meets all the necessary criteria, a radon test is required to measure the effectiveness of the newly installed radon mitigation system.

If radon levels reach above 4.0 picocuries per liter (pCi/L), then it will be necessary to install an active fan on the already existing passive radon system. This upgrade should reduce the radon levels significantly, with the target being below 4.0 pCi/L.

For more details, visit the Radon Control Methods section of the International Residential Code guide.

Radon Measurement Testing

As mentioned above, once you build the system, you have to test. You want to make sure that, after all that hard work that goes into protecting your property from radon gas, your system is actually functioning properly!

Now it’s time to call a radon testing pro. Here at Scott Home Inspection, we have full staff of NRPP-certified home inspectors that are ready to provide you with professional, reliable and efficient radon testing services. If you are in need of a radon test, feel free to reach out for more info or to schedule your test today.