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clcolley51
Existing insulation in walls
clcolley51

I recently bought a house that was built in 1999. It was constructed by the typical in and out contractor that did everything half cocked. My master bedroom is the typical situation of the room being colder/warmer than the rest of the home. 2 vents are located on the exterior walls. I got in the attic and notice hardly any insulation was in the attic as I could see the back of the drywall ceiling. It was cellulose insulation so I bought some and rented the machine and blew it in my self and have about 15" up there now. The room is still substantially colder than the rest of the home. The contractor installed cheap insulation in the stud cavities. The walls are 2x4 and I firmly believe that the insulation in the walls is 2" and doesn't fill the stud cavity. The front of my home is brick and the remaining walls are siding. The 2 outer walls of my bedroom are siding walls and I believe cold air is seeping through the skin and into the walls creating cold drafts causing my room to be cold. Additionally, I can feel cold air coming through receptacles and switches that are located along all walls that have siding. My question is; does any one know of a way I can add insulation to my exterior walls, that currently have insulation in them but does not fill the stud cavity, without having to cut significant openings or completely tearing out the drywall?? Thank you.

dj1
Re: Existing insulation in walls
dj1

1. First find out the R value for exterior wall required in your city.
2. Second, be aware that you can stuff and push more insulation to the point of zero air movement in the walls. I wonder how you determined that your cavities are not full right now.
3. You have to know that whatever type of additional insulation you pick, to get to the required R value, you will have to insert it into the wall cavities, but cutting holes in the drywall. Blow-in may require small holes, batts and rigid may require larger holes.
4. Exterior walls also have horizontal fire blockings, so every cavity will require 2 holes. Repairing 20 holes in a wall is more labor than installing new drywall.

In the past, when I was facing this situation, I tore down the entire drywall. Not only I could do a perfect job, I also got a chance to inspect the framing, check electrical and make changes and so on.

Between you and me, your exterior wall in not that large. Do the job right.

clcolley51
Re: Existing insulation in walls
clcolley51

Thank you for the feedback. I suspected the walls were not filled as when I was hanging items such as shelves and my TV, my drill bit was not pulling insulation out when I was backing out the bit. Also, as I stated in my post, I can feel cold air coming through every receptacle and light switch on the exterior sided walls. To me, cutting a 2" hole at the top and blowing it in is easier and cheaper than tearing it all down and reinstalling. Please let me know if you have anymore thoughts. Thanks.

A. Spruce
Re: Existing insulation in walls
A. Spruce

You can have an insulation contractor drill and fill your walls with cellulose insulation. I've only ever seen this done from the exterior, which I personally feel is criminal, since it breaches the weather proof shell of the home by turning the siding into swiss cheese, no matter how much epoxy they use to fill their 2" holes. Better would be if this were done from the interior side, drywall is EASY and cheap to repair and won't compromise the shell. Additionally, you can purchase foam wall plate insulators that go behind switch and receptacle covers to seal the boxes to the walls and help reduce drafts.

I would also suggest you have your HVAC system checked to make sure all the lines are in good working order. It is possible that some of the lines are crushed or damaged so that it can't provide sufficient airflow to your room. While you're at it, what's the condition of the system's filter?

keith3267
Re: Existing insulation in walls
keith3267

If you have faced batts in the walls now, you cannot add more insulation without first removing what is there. Most likely you do have faced batts because that is the easiest and cheapest to install, but it is usually installed incorrectly. Redoing it is not going to help much and certainly will not be cost effective.

If this bedroom is on the northwest corner of the house, that is part of the problem.

But if you do decide to tackle this, and you want to DYI, first remove all the drywall. Now you will likely find that the paper backed batts have the wings of the paper stapled to the inside edges of the studs. This is really the wrong way as it leaves a gap between the paper and the wall board. Cold air infiltrates the exterior siding, goes under the insulation and up this cavity via convection. Then it exits out the top of the insulation, effectively bypassing all the insulation.

I doubt the insulation is less than R-11 or it should not have gotten past the building inspector. I'm not sure you can even buy batts that are less than 3.5" thick, except for wrapping ductwork. Pull out all the staples and restaple the wings over the ends of the studs. The wings should even overlap a little, about a half inch. This removes the gap and provides a better vapor barrier. Staple the barrier at the bottom and top if you can. If you can't, use a quality barrier tape like the foil backed tape used to seal ducts to tape at the bottom anyway, top optional.

Before you reinstall the insulation, you may want to caulk all around each outlet and wall switch where the wires enter to junction boxes. Make sure there is insulation behind them too.

All of this will not have much affect on your utility bill, but the wall surface should be warmer so you will feel better. If you are doing it for some energy savings, you will be disappointed.

You can upgrade a little by either adding a 2x2 to each stud, moving the electrical boxes forward, re-triming around the windows and using new R-19 batts, but you will not recover the additional cost for that either. It will have a small affect on your utility bill, just not enough. You could move the electrical boxes in about 3/4", some new trim around the windows and put a 3/4" thick 4x8 foam panels over the studs. If you seal the seams of the foam panels, be sure to make a lot of cuts in the paper backing of the batts so you don't have two vapor barriers back to back. That is not good. Then put up new drywall. This will do more to warm up the room than anything else. But again, not cost effective.

clcolley51
Re: Existing insulation in walls
clcolley51

The room is on the NW corner of the home and takes the brunt of the wind. I am still exploring my options. My utility bills really are not bad, it is just that when I lay down at night it is freezing or hot. the insulation I added in the attic helped a bit. It may be 3 1/2" thick but it does fill the stud cavity. I have bought those gaskets that go over outlets and they are okay.

keith3267
Re: Existing insulation in walls
keith3267

A hot bedroom in the summer is no fun, but you do sleep better in a cold room in the winter. I let my north facing, upstairs bedroom get down to as low as 62 degrees and snuggle in between my memory foam bed and down comforter.

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