How To Install Blown In Attic Insulation
I have just completed an addition to my house. I've heard that blown in insulation is better than batts since covers the joists completely and leaves no open areas. Do you have any do it yourself suggestions?
Yes you are correct. Blown in insulation is better that batts when installed properly as it does seal the attic better.
First you need to measure your attic area that you plan on insulating. Most attics require a value of R-30, R-38 or R-49, depending on your climate and location. Once you know the square footage of your attic you can determine how much insulation you'll need by simply looking on the chart located on the bag of insulation.
Before you get started you will need to determine what materials you will need. Assuming your home has recessed lights, ceiling and bathroom fans and eave vents you will need the following tools and materials:
Loose Fill Insulation
Staple Hammer and Staples
Insulation Blowing Machine (Available at your local rental store)
The attic will need preparation before you can actually blow insulation into it. Make sure you are wearing a dust mask, protective goggles and a long sleeve shirt. Recessed lights must have flashing installed around them leaving a open space of at least four inches from the flashing to the light. Using a utility knife cut a piece of flashing of the correct length and form it into a cylinder shape, securing the edge with duct tape. Place over recessed light leaving a four inch open area. This allows for the heat to escape. Use the same process for any rented kitchen or bathroom fans in the attic area.
The next step is baffles. This is a chore nobody enjoys. The baffles need be installed by using your staple hammer and install them where the ceiling joists intersect with roof rafters. Make sure you only install the baffles over the vents and that they are high enough so the vents will not get covered with insulation. Now that you've installed you might want to climb out of the attic and give you back a much needed rest.
The next step of preparation is to make a dam around the attic access hole. The easiest way is to cut a few extra cardboard baffles into lengths of about 4 inches above the amount of insulation you plan on installing. Simply staple them around the perimeters of the access hole. This will allow for a uniform depth in the insulation you are blowing in.
So you do not have to keep crawling in and out of the attic it's best to have another person outside helping you load the insulation blowing machine. Hint: If you're using fiberglass insulation have your helper add about a cup of water per bag, spreading it over the top after its loaded into the machine. This will help cut down static electricity when you are blowing the insulation and it will lay down more even when installing it. After the bag of insulation is loaded into the hopper it will take several minutes before the next bag is needed. Do not let your helper be lazy. Have him get on the ladder and pull excess hose out of the attic for you so you do not get tangled in it.
I've found blowing insulation into the attic is a simple process. Start and the far ends of the attic. Going back and forth make sure its level and smooth. Make sure to get all areas of the attic and do not fill any vents or recessed light areas. Take a tape measure with you and check the levels once in a while. As an example, if your installing an R-38 of fiberglass insulation you would want it to measure 16 inches deep. As you work your way back near the attic access make sure your helper is getting that extra hose out of the way. When you get to about 6 feet from the access hole stop the machine so you can get on the ladder. Once on the ladder finish installing, making sure to bring the level evenly against the dam you previously built.
The final step is to place a piece of batt insulation in the access hole and carefully put the attic hole lid back into place. Now your done! Stay out of that attic as much as possible from this point as loose fill insulation that has been stepped on or crushed looses it's R value.