insulation
I recently bought a house and Ive found out the insulation is not good enough in the exterior walls. Is there a way that I can just cut a small hole and maybe blow in insulation into the walls instead of tearing down all the drywall?
Is this a diy project or should I hire someone?
Hoisting the insulation with the drywall panel is a bad idea. I would instead install fiberglass bat insulation between the joists. You could use the kind that is faced with paper and staple it to the joists for added support. If just plain batts are used then you may need to add some type of staple on stripping to help hold the batts in place. Install all of this except for one small area where you can go up and put in more of the loose insulation above the fiberglass if that is desired or needed. Finally close off the small area by pushing up an oversized bat that covers the opening from above and then install the final piece. If using the paper backed staple that in place. If the ceiling previously had some type of vapor barrier you need to install similar material on the bottom of the ceiling joists.
Now you would be ready to install the new ceiling drywall.
Yes, Rigid foam (XPS and ISO) boards are frequently used in exterior applications, and can be a great option for improving efficiency. There are a couple of issues with your proposed approach, though:
On a wood frame house, you'd want to use this order:
Here's a visual from Fine Homebuilding, which has a couple of good articles on this:
Note that adding foam on the exterior of your house complicates some things. You will likely need to redo the trim on your windows and doors, which will become more in-set. These inset areas will need to be flashed properly or you will have leaks, which have more potential to do damage when you've got multi-layered, thick walls that could trap moisture. If done well, you can get very good insulation. But make sure to work with someone who knows what they're doing!
Best Answer
There are companies that will drill 2" holes at two or three places in each stud cavity. You're left to repair the drywall if it's done from the inside. It can also be done from outside, through the wall sheathing, if you're replacing siding. In this case, patches aren't really needed. House wrap covers the holes.
I don't know of anywhere that rents the equipment for that. The insulation medium is often beaded polystyrene, but it could be fiberglass. It's fairly specialized. You'd have to check around your area.