Third Party Green & Energy Code Reviews
Window poly-seal
Required for:
New construction
Additions
Remodels that include any of the following:
- conversion of non-conditioned to conditioned space
- roof replacement
- new exterior doors and/or windows
- new HVAC systems
- increase in power consumption such as new lighting
Eave baffles
Top plate poly-seal
NFRC window sticker
Bottom plate poly-seal
Insulation dam
Insulation netting at attic wall
Plan Review
Email a full set of plansand any relevant cut sheets to mark@dfwgreencode.com
The plans must include:
- Area tabulations per floor for conditioned & non-conditioned spaces
- Dimensions & ceiling heights
- Door & window schedule
- Exterior finish materials
These are not required but helpful
- R-values and location of insulation
- U-factor & SHGC for windows
- HVAC sizing & SEER rating
2021 IECC Highlights - climate zone 2A (Dallas, Tarrant, Ellis & Johnson Counties)
2021 IECC Highlights - climate zone 3A (all other North Texas Counties)
2018 IECC Highlights - climate zone 3A (all of North Texas)
2015 IECC Highlights - climate zone 3A (all of North Texas)
After my review I will provide you with an IC3 report for new construction or a REScheck report for additions and remodels. You will also receive an energy compliance path form if required by your city to turn in with your permit application.
Inspections
Energy code inspections are required throughout various phases of construction. The first is at rough insulation prior to drywall. Please note that some cities require an additional inspection of the poly-seal prior to the insulation being installed. I will then need to do a energy final inspection after the following are complete:
- Attic is insulated
- Permanent power is on
- HVAC system is fully installed and running
- All exterior doors are weatherstripped, including doors to the garage and attic
- All exhaust fans are installed and operational
Below is an overview of best practices and some of the items I will be looking at during my inspections.
Insulation and Sealing
Houses are built with various barriers to limit the movement of air, heat and moisture between conditioned and unconditioned space.
The moisture barrier consists of the roofing, the exterior sheathing and vapor barrier under the foundation. The sheathing will either be wrapped with a water resistant fabric such as Tyvek or have an integral moisture barrier such as ZIP board. A vapor barrier should be installed under the slab or on the soil in a pier and beam foundation. If not controlled, excess moisture and humidity can lead to inefficient HVAC performance and eventually mold growth.
The air barrier is generally the finished gypsum board walls and ceilings, and sub-floor in pier and beam foundations. Since there are many penetrations in the gypsum board such as outlets, light fixtures, registers, etc., it is essential that the framing behind the drywall be properly sealed. Poly-seal is needed at the bottom plates at the slab or sub-floor, and at the top plates where the gypsum board will be placed. Any gaps in the studs or exterior sheathing should be sealed as well. All windows and exterior doors should be poly-sealed around the shim space at the edges. All penetration in the top and bottom plates along with any thru-stud penetrations should be sealed. Please note that any penetrations in framing cavities should be sealed with fire retardant poly-seal. This will keep any potential fires from spreading into adjacent framing cavities or the attic. Low-expansive poly-seal should be used on the windows and plates.
The thermal barrier, also known as the thermal envelope is where the insulation is placed.
Wall insulation must completely fill the stud cavity. It should be the corresponding size for the stud center width and be the proper depth. If the walls are framed with 2x4, then R13 or R15 is appropriate. If 2x6s are used, the insulation will need to be R19 or R21 to be in contact with both the sheathing and gypsum board. Fiberglass batt, mineral wool, blown-in-blanket fiberglass or cellulose and open-cell spray-foam are all commonly used insulating materials.
The attic insulation is probably the most critical due to the constant exposure of the roof to the sun. There are several ways to insulate the attic. Attics are either ventilated, while being outside of the conditioned envelope, or non-vented or encapsulated within the conditioned envelope.
- For ventilated attics, there should be proper airflow with outside air being drawn in from either soffit or gable vents then vented through ridge, turbine or mechanical vents at the high point of the roof. The most common way to insulate an attic is to use blown-in fiberglass or cellulose. The required R-value in North Texas is between R38 to R49 depending on the code or climate zone. The depth should between about 14-18 inches and the installer should add a few inches to account for settlement. If vented soffits are used, eave baffles will need to be installed to maintain airflow and prevent the loose-fill insulation from clogging the vents. Similarly, If the house has varying ceiling heights, insulation dams should be installed to keep the blown-in insulation from falling down to the lower ceilings. For insulated attic walls that have gypsum board on the conditioned side only, the insulation must be secured to the studs as it will gradually fall out over time. This can be done with netting or straps. Lastly, any attic access doors need to be weatherstripped with a threshold like any exterior door while pull-down stairs should have an R-value of R10 minimum according to the 2021 IECC.
- For foam encapsulated attics, the foam at the roof deck should be a minimum of R30 (+/- 8"). Prescriptive compliance requires between R38 to R49 which is not feasible for spray-foam. Therefore, the performance alternative must be used. The 2021 IECC specifies that any component cannot be reduced beyond the 2009 IECC prescriptive values, which is R30 for roof or ceiling insulation. Garages and attic space above a garage should not be within the conditioned envelope. Garage doors are made of thin steel and are not tight fitting which basically acts as a giant hole. To avoid this, either the garage attic and the main house will need to be thermally separated or the garage ceiling will need to be insulated. Extra consideration will be needed with the attic access as they are often located in the garage. It is better to install high efficiency natural gas appliances in the attic. The exhaust is much cooler and is direct vented via PVC pipe rather than a hot flue which may not be in direct contact with the foam insulation. Because there are no vents to provide air-flow, the attic may contain excess moisture that has no where to go. A good solution is to install one supply and one return in the attic to cycle the air. Foam encapsulation typically results in a tighter house and since the HVAC equipment is within the conditioned envelope, it shouldn't work as hard. There are some things that must be considered with foam encapsulation. It is essential to size the HVAC system properly. Oversized systems can result in short-cycling and moisture not being fully removed from the air. Over time this excess moisture will get pushed into the foam and eventually onto the substrate behind where it will become trapped and lead to mold growth. Also, a very tight house can build up higher levels of CO2 just from the occupants so whole home mechanical ventilation is required by code.