Does your job require a Quality Insulation Inspection (QII)? This is becoming much more common now days as CA's green building requirements slowly become more and more strict. All jobs require the normal insulation inspection by the city inspector. This is basically a check to make sure the insulation isn't missing and that it is the correct type. It is a very quick inspection and if the inspector sees insulation, you pass. A QII is very different. With a QII, a private company will come out to check your insulation to ensure it conforms with CA's quality requirements. If you fail, not only will this delay the job, but it will also cost you more money to get another inspection. The standards set by the CA Energy Commission can be somewhat hard to understand, so in this article I will take you step by step through all the requirements and how to pass this inspection on the first try.
The rules for CA QII can be hard to follow if you don't have much experience in this area. Particularly, it is hard to know which rules apply or don't apply to your specific project. In general, it is best to conform to all requirements and we will assume that is the case in this article. QII requirments breakdown into 2 categories:
The thermal barrier requirements refer to creating an airtight thermal barrier. Basically you are ensuring that the inside of all your exterior walls are airtight. This is done before you place any insulation and greatly increases the energy efficiency of your home. The insulation requirements ensure that all the insulation is cut with a tight fit, no gaps in between pieces and all insulation has good loft (no stuffing). This makes sure that the insulation keeps it R-value and works efficiently.
In order to create an airtight barrier, we are going to need to do some sealing. Your best friend for this process will be some type of expandable foam. You can find it at you local hardware store or insulation supplier. The first thing to seal is all of the penetrations going through the top and bottom plates of your walls. This includes electrical wires, plumbing pipes or even open holes. If you have shearing panels on your exterior, you must also seal the top and bottom wall plates against the shearing. This is shown in the picture below.
Looking at the picture above, you can see how there is a horizontal line of sealant between the OSB shearing and the top plate of the wall. The hole for the wire going through the top plate has also been sealed. Now this bay is sealed, creating an ideal barrier. We do this along all exterior walls ensuring that the top an bottom plates are fully sealed. Additionally, you must check all interior walls for wiring, plumbing and other penetrations that need sealing. There won't be any shearing to seal against, but interior walls will have penetrations needing to be sealed. Lastly, you need to seal the exterior wall bottom plates to the sub-floor. Sometimes the bottom plate may be on concrete. In this case seal the plate against the concrete. In the pictures below we have pulled back the insulation so you can see how we seal everything.
The last order of business for our thermal barrier requirements is to install a drywall gasket along the top plate (the pink foam strip in the pictures). In the picture below you can see a pink foam strip that has been stapled to the wall top plate. This ensures that no air will leak through the drywall. When the drywall is first installed, it makes a good seal. But after a few years, the house starts to settle and that tight seal can become quite the air leak. So QII requires a drywall gasket installed on the top plate of all exterior and interior walls.
Sometimes you may run into gaps between studs that are a little to small to get insulation into. This is not an ideal framing practice but it does happen. If this is the case then you should put sealant in there as well. In general, any studs separated by less than 3/4 inch should be sealed with foam. Once you have sealed everything you are done with the thermal barrier requirements. Next is to actually start placing the insulation.
The key to correct installation of your insulation is to make sure that you cut everything to size very well. It is all too common for people to stuff a large piece of insulation in a small area. This is temping because it is easy and saves time. However, this lowers the R-value of the insulation and is not acceptable for a QII inspection. I recommend cutting the insulation 1/2 inch larger than the area it goes into. This will ensure the insulation has plenty of loft and also is able to hold itself in the area with friction (it is no fun when insulation falls out and lands on your head). You also want to make sure that there are no gaps anywhere. This includes against the studs, around electrical boxes and also between pieces of insulation.
Notice in the above pictures that there are no gaps anywhere. The insulation has been cut to size and there are no wrinkles. The insulation should set in easily. Any obstacles such as electrical boxes and hardware are cut around. Do not try to smash the insulation in next to the electrical boxes. This will fail inspection.
This job was just recently inspected and passed with flying colors. The main thing to remember is take you time and make good cuts. When the inspector comes in and sees a clean job, they will generally pass you instantly. If they see wrinkled insulation or gaps then they will check everything over very closely increasing the chance of a failure.
I hope this has helped with understating CA QII. If you have any questions or comments please leave them below
Good luck on your next project!