Insulation questions

[Dr Batsen D Belfry]

All,

We are planning on replacing our 1st floor windows and reinsulating the attic this fall, but I have questions

1) Does anyone have experience with cellulose loose fill insulation?
2) We are hoping to blow this down the walls as well as in the attic. How will this affect/be affected by knob and tube wiring? I don't want to set the house on fire...

Thanks,
DBDB

[RC]

1. If the house is so old that it has Knob & tube wiring, there are

fire stops in the walls. Also cellulose will settle after a while when placed in walls.

[Dr Batsen D Belfry]

2. Hmmm....So if cellulose down the walls is a poor option

any ideas on insulating the walls?

This is an old house with plaster interior walls and brick exterior. Ripping the alls apart to insulate is not an eeasy/feasible choice.

Thanks,
DBDB

[whistle]

11. See the links, blown fiberglass seems to work well without the....

longer term compression problems. Also, need to ask about the hazard of using the cellulose product which is recycled newspaper with chemical fire retardants. I don't trust EPA on approving such material for use around humans. These chemical fire retardants cause symptoms similar to mad-cow disease.

[kestrel91316]

14. Maybe you could redo the walls inside room-by-room rather than

one big project. I think most folks could manage that by themselves? Rip out lath/plaster, put in fiberglass batts, put up sheetrock, tape and paint it. One little room at a time! You can do it!

[whistle]

3. cellulose loose fill insulation is a bad choose unless you are...

...willing to go up in the attic at least once a year to rake and fluff the stuff up! It has a tendency to naturally compact itself, thus reducing the R-factor efficiency. It is far less efficient than blown fiberglass and even less efficient than the fiberglass rolled type insulation. That was my neighbor's experience over 20 years and I vowed I would not ever use the stuff in any house I built or owned. Here are some links to explain the differences:

http://www.eere.energy.gov/consumerinfo/factsheets/insulate.html

http://www.naima.org/pages/resources/faq/faq_home.html

[Ian David]

5. If I want to add more rolled fiberglass to my atic...

do I need to remove the old stuff first?

I was hoping I could just roll-out new stuff right on top of it.

And then nail some paneling down on top of it.

[Nihil]

6. OK but be careful

You can roll it over the existing stuff (just adding depth) and, for
an unused attic, it is recommended to do it crosswise to reduce the
gaps.

You need to be careful though if you are putting any form of board over
the insulation. The insulation relies upon the overall volume of the
wadding to retain the heat. Crushing it with a board reduces its
effect. If your rafters are deep enough that the boards will sit across
them even with the added depth all well and good. Nice quick job.

If not - i.e., if the fibreglass sticks higher than the top of the
rafters - then you will either need to add a spacer on top of each
rafter or accept that you will be losing some of the effect of the
additional insulation.

In my previous house, I opted for the latter as there wasn't much
"crush" by the floorboards and I was intending to put a layer of carpet
over the boarding anyway to boost it back up.

[Ian David]

8. I used to have a problem with my pipes freezing during the winter...

To solve the problem, I put a couple high-wattage flood-lamps in the attic, which helped a lot. Of course, it's a fire hazard.

So, since the hot and cold pipes are so close together-- in some places, this includes the ones for the forced hot water heat--all I did was put some insulation over them. Now, the hot water pipes keep the cold water pipe warm.

I just have to keep the hot water running a little when I leave the house. It seems to work just as well as the flood-lamps, but without the fire hazard.

[RONSTOO]

13. wrong

cellulose is much better than blown fiberglass. I know the difference as I work in insulation.

[Divernan]

4. W/increasing fuel prices, this is very smart time to insulate!

Heating costs for natural gas will skyrocket this winter. I was just talking with a friend about how to improve heat retention in my house for the winter. I have a metal air duct heating two bedrooms above my garage. The duct is just below the ceiling of the unheated/uninsulated garage- lots of heat loss there. I also have an old wooden garage door with a one inch gap across the bottom when it's closed. So I'm going to have the metal duct wrapped with insulating sheets, get a new insulated garage door, and add another layer of insulation to my attic floor. I really expect to save many hundreds of dollars in heating costs, and it will also pay off in air conditioning costs in hot weather.

On edit: I replaced all my old metal framed windows with Pella windows over a period of the last few years and am very happy with them. Something to consider when replacing windows is that you can change the size of the windows. I have beautiful woods behind my house, overlooked by windows in the kitchen and two bedrooms. I enlarged the rear kitchen window and brought the bottom level with the counter, so I get a great view while eating or working there. In the MBR, I replaced a wide, high and shallow window with sliding French doors and the following year put a small (10 by 12)wood deck there - great for bird-watching, enjoying sunsets and private sunbathing. In the other bedroom, again, I enlarged a high, small window with a larger one that comes down to the level of my computer desk/work area. It's all one pane of glass and again gives me a beautiful view of woods and wildlife while I'm working (?) at my desk. One day last winter I saw a flock of about 14 wild turkeys fly into the woods - I also see deer and ground hogs, and one red shouldered hawk..

[Ian David]

7. I've got Newpro windows and doors. Love the windows, the doors are Okay

The locks on the door keep coming loose in their holes, and one of the doors has developed brown stains on the outside.

Otherwise, the doors are good, solid, and very well insulated.

The windows are actually pretty easy to break into, although advertised as more secure. I know, because I had to break into one when I locked myself out.

Otherwise, I love the windows.

[Delarage]

9. I used it......

My 55-year old house had a floored attic with very little cellulose insulation under the floor (some spaces had none). I bought the stuff at Lowes and got free use of the blower (I had a friend standing on my deck feeding it into the machine while I dragged the very long tube around my attic). I just used it to fill up to the top of the joists (or whatever they're called) and then rolled thick fiberglass bats across them so the joists supported them). I estimate that I have R-40 in there now. I noticed an immediate 33% reduction in gas use in the winter. Just make sure you use baffles so you don't blow the stuff into your eaves and block ventilation.

I read about blowing it into the walls and I think I found that it's generally a poor choice because it settles so much. There's something that has sticky stuff with it that can be sprayed in that does better, but it is questionable about the cost/benefit.

[skids]

10. Don't neglect airflow.

Proper cycling of air through the building as a whole can reduce heat loss -- basically this entails blowing the rising hot air back down to the floor on ground level (or basement, if heated.) Ceiling fans can help a lot but there are better whole-house ducting systems.

[RONSTOO]

12. I sell insulation

you must not blow on top of knob & tube wiring unless a certified electrician checks its safety. Bottom line you should have it replaced as its an electrical hazard which has been known to cause electrical fires.


pm me for more info ...I have over 15 yrs in insulation business

[Porcupine]

16. I agree. I'm a building maintenance tech.

You really need to pull walls and rewire your house. It can be done safely and reasonably by a determined and carefull DIY homeowner.

Do not let that wiring stay. Knob and tube wiring is wrapped in rubber and cloth insulation that is VERY brittle. If it is disturbed the insulation has a tendency to flake off. This has already happened to much of your wiring; you just can't see it. Replace it or ping the lounge for a fire inspector.

[Piedras]

15. Yes, I used cellulose

I live in an older home built in the 1920's in coastal California. It had no insulation when I bought it. It was cold and drafty in winter. Hot in summer. About 20 years ago I bought bagged cellulose insulation, borrowed a blower from the lumber store, and insulated the house with the help of a friend who ran the blower from outside in the driveway. Messy but not hard to do.

My house has balloon framing so I was able to blow insulation down from the attic into most of the walls. The house had knob and tube wiring. After insulating the house it was no longer drafty and it retained heat much better in winter and kept summer heat out longer.

Later I added on to the house and removed all the old knob and tube wiring replacing it with "romex" type wiring.

When doing the remodel/add on I opened most exterior walls in the old part of the house by removing the lath and plaster. The blown in cellulose insulation hadn't settled, it was firm, filled little every bit of the wall space (better than fiberglass batts can0. Where I didn't remove insulation to replace the knob and tube wiring with romex I left the cellulose in place. Used new fiberglass batts in wall areas with new wiring. Covered the bare walls with drywall.

In the attic of the older part of the house I left the existing cellulose insulation in and had a contractor blow more cellulose over it to get us over R30. Ten+ years later it doesn't seem to have settled.

One thing to watch for is to make sure the insulation contractor doesn't fluff up the insulation with too much air as they blow it in. Then it will settle more and you may get shorted the R value you expected and paid for. Have then count and show you the empty bags of insulation to prove you got what you paid for. The bags tell how many square feet coverage they provide for various R values.