insulation in middle tennessee

[spinguy]

I am building/re-building a home in Nashville..what is the preferred method of insulating sub areas and exterior walls??I have been told to use unfaced batts on the subfloor...and I have been told not to insulate because of mold and rot...waddyathink>>>>

[cowboyjg]

Mold and rot are the result of moisture build up and no ventilation. If you have good air flow and no leaks or water infiltration issues you should be ok. As far as material choices are concerned, there are many. If initial $ outlay is not too big a deal there is a spray-on material called isonene that is fabulous. The return on the energy bill could very easily justify it. The return though won't be immediate but would be worth it. It is not a DIY project. It is used mostly in commercial projects but has been getting more attention from the residential building community.

The air flow is relative to attic and floor areas. The water infiltration is mainly relative to the walls and around windows and doors but can apply to all the areas.

Insulation is critical. Keeping air leaks to a minimum is also part of that. Using door and window weather stripping. electrical outlet and switch boxes are know to leak badly. Check with your local electric company for additional things you can do to insulate and make for a more efficiant home.

[twstanley]

As far as I know you want all your exterior walls and floors insulated. The walls you can use faced batts with the facing towards the interior of the house, use the right thickness of batts for 2x4 or 2x6 walls...most likely 2x4 for Tennessee.

For the floors, if it is over a crawl space or a basement, either way use unfaced batts between the floor joists. The crawl space can have plastic put down over the dirt to stop moisture coming up into the crawl space. You can also check local codes and practices to see if you should have venting from the crawl space to the outside. An addition was put on our house at one point, it has a crawlspace vented to the outside, it has unfaced batts between the floor joists. I need to get in there this fall and stuff the batts back up as they are falling down. Simpson strongtie has some little stiff wires that are cut for use between floor joists to hold insulation up.

http://www.strongtie.com/products/connectors/is.html

I have found those very handy for quick fixes to sagging insulation between floor joists, especially if you are on the side that the facing is not on.

[roypat2126]

Hey Spinguy,
Not having a lot of experiance with what your looking for but I can relay my own, and perhaps be of slight benefit for you.

I'm an hr south of Nashville and in my crawl space I noticed little black "spore" growths on the floor joists. (folks previous, left the crawlspace door open as they had big dogs that slept under house. We moved in and I keep the door shut as skunks, snakes and other vermin are always around, you know, country life) Thinking this was mold, at any rate something that I didn't want , I installed faced insulation in my crawlspace and put down plastic on ground as moisture barrier. .although I didn't do plastic for a couple years. I used the metal wires twstanley mentioned and they work good to hold the insul. in place, although without the moisture barrier they can rust really fast and fall away if too much "spring" is put on um.

An in-law from Miami area recommended installing the plastic to underside of floor joists, which might be a good solution for both moist. bar. and holding insulation but I opted not to do that as I wanted air circulation around the insulation, thinking this might benefit the structure.

Had termites in my old barn so as a precaution, a pest control co. sprayed crawl space, and they recommended I install one extra vent in my c-s which I did, using the type with thermal coil to auto open/shut. They work very well. I had to install a fan under there as well, to combat air/moisture stagnation. My AC ducts sweat in summer...re-insulated them but they still drip although the dripping noise has never kept me awake [img]/forums/images/icons/smile.gif[/img]

For your walls, in my opinion, the best is the expanding foam which seals out air infiltration as well as provides quality insulation, and if your budget holds this would perhaps be the best alternative. The R factor for insul. is basically governed by the thickness of your walls. 2x4 studs use R19 batts and 2x6 will be around R25. The higher the R factor the greater the insulation quality.

In rebuilding your wall structure (I assume you are doing it with wood), create ways in which you can seal all holes or places of potential air infiltration , such as where the sole plate meets the foundation, the areas where panels join (if not centered properly on the stud) around edge of ceiling and floor panels, and corner wall joints. And on top or bottom wall plates where the elctrical wires and plumbing run through. These are usually drafty areas. (also the mounting box for ceiling fans, lights and wall outlets and switches, can be sealed effectively. Caulk all cracks /crevices around doors and windows (here, you can use that "great stuff" spray foam). and use house wrap (Tyvak) on exterior walls. Any little small crack that air can penetrate you'll want sealed. In a blowing wind it will find a way to get through . If it's cold air in Feb., that blows say, around the end of vinyl siding, if it finds a spot to penetrate the wall, because moisture content is greater then the inside heated space it will bead up on the warmer material, cause moisture in your wall where you can't see it until it's too late.

The air exchange ratio in attic space is a must for economy and interior envelope temperature comfort and stability..

Maybe this answers some of your questions, and I hope you have great success with your project, Have a blessed day,
roy

[Pat]

You can buy thermostatic controlled vents for crawlspace. Put vapor barrier over all dirt.

Insulation priorities in descending priority order are: ceiling, walls, floors (or stemwall) and foundation (thermal break between foundaton and soil.) Seal up all soures of infiltration. If you really want to go whole hog add thermal drapes and window treatments or use removable decorative window insulation to put in place at night in winter and on the south side or east and west windows in summer.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[roypat2126]

I installed faced insulation in my crawlspace

Hey Pat,
Just to clarify, I installed insulation faced side up against floor, and 6mil blk plastic on ground with approx. 6-8" up-turn against foundation walls.

Shortly after we moved in I used "great stuff" and sealed anything that had a hole or crack in crawlspace. Did same in attic where electric runs down through walls. Main bath tub/shower didn't have insulation over it so pushed lose fill insul. down around it and covered entire opening with plastic then spread insul. over top. This made the one piece fiberglass insert walls less prone to air infiltr. and allowed it to reach room temp. (Just nicer to shower in now) Retiled the bathroom and installed electric heater in the mud....really makes great difference on cold winter morns.

Have a blessed OK day, Pat [img]/forums/images/icons/smile.gif[/img]
roy

[Pat]

Roy, Some folks insulate the stem walls instead of the floor. Sometimes cheaper. Unless the crawl space is drafty in winter it works OK. Some heat gets under the house and warms the dirt a mite but this is a minor effect, especially in a temperate climate like you have. It protects the exposed pipes from freezing and makes it WAY more comfortable should you have to get in there. It probably reduces the prospects for condensation as well.

Either way, stem wall or under floor (or under slab) ceiling and walls are way more important for insulation.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[Handyman]

Hello Spinguy... lebanon here [img]/forums/images/icons/grin.gif[/img]

Look I did research for two yrs before building my house 2 yrs ago and this is how I did my crawl space.

I used foam wrap for the pipes that I installed up within the floor joists, then R 19 between the 2x10 joists leaving about 3-4" between the actual floor and the top of the insulation. The heat from your home will be trapped in that space and with the added foam wrap around the pipes... I do NOT have to worry about my pipes freezing.

By doing the above, you will NOT have to insulate the exterior sub walls. The reason I did NOT insulate the exterior wall is because of termites. They need a way to stay moist to travel and by putting a layer of insulation against the wall, you are giving them a way to travel to your floor joists and wall undetected as well as an eviroment they will thrive in.

Another thing that was mentioned that I differ with was I cut my plastic covering the ground about 6" away from all the piers and walls. Agains allowing the ground to be as dry as possible close to any structure leading up.

I am not sure if they go to Nashville, but I know a guy here that can insulate your floors/house cheaper than you can buy it and do it yourself... serious !

I also used Tyvek for the exteriour walls and heatshield on the west wall inside. 14" or R38 blown in in the attic with a power attic fan.

Result... I rated as a Energy effency level of 86.3 (energy Gold) according to TVA [img]/forums/images/icons/grin.gif[/img]

My highest bill has been $130 (winter) and $54 AC (summer)so far and that was last winter for a 1700 sq ft house with a 2 car garage

I also know a GOOD AC man too.
PM me or email me with your # and I can call with the info of these guys when I get home.