Quality Insulation Inspection
Unsure about insulation requirements for your construction project? Learn more about Building Codes!

Quality Insulation Inspection Requirements
If you are planning to build new walls, California requires compliance with Energy Efficiency Standards. Codes are enforced with either insulation installer verifications or quality insulation inspections. Efficient insulation ensures that outside air does not affect the temperature-controlled air inside. Therefore, the HVAC won’t be overwhelmed, as each system in the building can work together. Code regulations apply only to exterior walls and ductwork for this reason. Still, insulation on interior walls is a good idea. Why? To prevent temperature fluctuations from room to room. Unless you’ve thoroughly studied Title 24 Building Codes, it can be difficult to determine what’s required in each situation. That’s because there are different rules depending on what type of wall is being built, and what materials are being used.
For starters, there are distinctive requirements for interior walls, exterior walls, attics, roofs, ceilings, soffits, ducts, and floors. Then, you must also take into account what type of framing (metal, wood, etc) is being used. What a mouthful! Rather than trying to DIY, we recommend you seek the guidance of certified experts. From planning to implementation, an Energy Consultant’s job is to assist. That’s where we come in! Our HERS Raters stay up to date on all current codes, so you don’t have to. However, it’s still important to understand the basics.
There are a few key components that affect the energy efficiency of insulation:
1) R-Value
R-Value stands for heat flow resistance. A higher R-Value means greater resistance and thus better efficiency. Better efficiency means more comfort and lower energy bills. The factors that affect this measure are type, thickness, and density. Average values range from R13-R60. Typically, attics and exterior walls require the highest heat resistance.
2) U-Factor
The measure of thermal heat transfer. Where R-Value rates the materials of the insulation itself, U-Factor takes into account all of the walls’ elements including the size of air gaps and wall thickness.
3) K-Factor
Thermal conductivity is rated on a scale of 0-1. Lower conductivity has more efficient performance.
4) C-Factor
C-factor is thermal conductance based on thickness. In other words, it rates the flow of heat through a particular quantity of material.
Types of Insulation and Radiant Barriers
There are many different kinds of insulation to pick from. Some are more fire-resistant, sound-resistant, and water-resistant than others because they are made from a variety of materials. In California, the installation of formaldehyde foam is banned. So, let’s get into the options available to you:
1) Spray Foam
Spray foam is a semiliquid that molds to the surfaces it’s applied to and dries into a solid. It’s usually used in conjunction with other types of insulation, but it’s applied first as a base. That’s because it’s perfect for sealing air gaps around outlets, fixtures, walls, windows, and doors. On top of preventing air leakage, it can prevent condensation, sound transfer, fire, and mold growth.
2) Fiberglass – Wools, Batts, Blow-In, Boards
Fiberglass is a common element of insulation that comes in many forms. It’s made from a combination of plastic and glass fibers, making it fire-repelling. It comes in many forms such as glass wool rolls, batt blankets, loose blow-ins, and rigid foam boards. Often, rolls and blankets are covered in Kraft paper on one side to prevent water vapors. Alternatively, fiberglass insulation wrapped in foil can be used as duct insulation. Commonly used in attics and non-condition spaces, average insulating values for ductwork are between R6-R8.
3) Mineral Wool – Rock or Slag
Similar to fiberglass wool, mineral wool is made from a combination of wool and tiny fibers. Except, instead of glass fibers and plastic, mineral wool is made from organic compounds such as volcanic rock, limestone, diabase, and/or slag (from steel). The recycled materials in this product make it a more eco-friendly alternative to fiberglass. Furthermore, mineral wool is dense, giving it a higher R-Value.
4) Polyiso Sheathing
Pressed polyisocyanurate foam creates rigid insulating boards that are known as polyiso sheathing. They are more efficient and resistant to heat flow as compared to fiberglass foam boards. Foam boards are thin and light, minimizing space, labor, and materials.
5) Cellulose – Blow-In, Spray-on, Boards
Cellulose is another name for plant fiber, making this another environmentally-friendly option. Loose blow-in type insulation is mixed with treated newspaper. Spray-on cellulose is in a semiliquid form that applies like spray foam. Lastly, it also comes in the form of foam boards which have an even higher performance than polystyrene foam. One great advantage of cellulose is that it’s non-toxic and can thus improve indoor air quality. We give this product our green stamp of approval!
6) Radiant Barrier
Radiant Barriers are made from a highly reflective material to repel thermal radiation. Either paint or foil is placed on the inside of the ceilings’ roof/attic space as insulation. Another type of radiant barrier is bound to the roof shingles. These “cool roofs” reflect radiant heat. Radiant Barriers are about 97% reflective and require an air gap in order to prevent heat transfer. The roof is an important part of the building to insulate because they receive a majority of direct sunlight.
7) Insulated Concrete
Concrete walls can have insulation built in, making them strong and resistant to environmental factors. These designs are most common in low-rise commercial and residential structures. They look exactly like regular concrete walls, except they are slightly thicker. With ICFs your project can meet energy code standards with much less installation hassle.
8) Structural Insulated Panels
SIP’s carry the same concept as insulated concrete, in that they’re created under factory-controlled settings. Thusly, their efficiency ratings are consistent and reliable. Structural Insulated Panels consist of foam insulation sandwiched between two pieces of plywood. They’re used almost exclusively on exterior walls, as they result in quick and easy construction of framing. Another bonus is that they aid in preventing building leakage and contaminants from the outdoor air.
Quality Insulation Inspection Process
An energy consultant can help you select the correct insulation during the design phase. Otherwise, closely examine the Title 24 regulations that apply based on what year the permit was pulled. It’s also going to depend on what climate zone the structure is located in and the type of structure being built. A little extra time spent during this phase can speed up the entire process.
After your plans have been approved, the next step is an at-frame inspection. A HERS technician will perform the entire Quality Insulation Inspection. First, we must visually ensure all cracks are sealed before the insulation goes in. That means the installer should use spray foam or caulk to seal windows, doors, fireplace flues, outlets, exterior penetrations, and in-between wall cavities. Then, we come out again once the insulation is installed and before the walls are up. At this stage, we are verifying the types of insulation going in, as well as R-values and U-factors. Sometimes, this might take two additional trips if there are layers of insulation such as spray foam and batt.
The Building Department requires these specialized inspections to be performed by an energy efficiency specialist to ensure that Energy Standards have been followed according to the plans. Lastly, we enter this data into a certificate of installation for the Building Department to access. All of your work is quality assured so that the energy compliance process goes smoothly. Contact us for a free quote today! Also, you can continue reading about insulation in our blog post about ‘DIY Insulating Paint‘.