Good grief--insulation question

[Betsy]

Well, last year I was hell-bent on saving money on heating and insulated EVERYTHING. I tucked insulation up between the sill plates & the floor. I wrapped all the steam pipes in the basement to direct the heat upstairs. I put plastic over every window. I insulated every hot AND cold water pipe where they were accessible. I put plastic over every transom and the lites on the sides of the front door.

Lo and behold: today I walked over to the window bumpout to dust and my stocking feet were instantly cold. I realized: where my old house has a sort of bay (the 3 front windows and the floor under them jut out so the room isn't square, it has a sort of built-in bay--I don't know what to call it!), THIS part of the floor actually is part of the porch! And there is NO INSULATION under it. The dining room does the same thing! YIKES! I must be just pouring money through those floorboards!

So tomorrow I'm crawling under the porch to see how the joists run and what I can do to insulate.

What would you recommend for this application? Would fiberglass or rigid foam be better? Should it be foil backed? I am worried that anything I put up that is outside will be a haven for bugs and wood rot. Is there anything I should do to prep the area first? How do I get it to stay in place?

Thanks for any help/advice.

[Tom Miller]

What's under the area? Dirt? Is the area underneath enclosed with concrete or blocks like the basement? Or sheathing of some sort? Or open to the air or latticed? Is this area open to the basement or separated from it by the house foundation? Describe it. This could make a difference in ways to insulate. I have a dirt-floored crawl space under my kitchen, for example, but it is connected to the basement by an opening at the top of one wall (there is a huge boulder in the crawl space -- about as big as a couple of station wagons, I'm thinking. When the house was put up in 1921, they simply left it there and built the kitchen bump-out over it). Anyway, I was able to "insulate" by simply laying several heavy sheets of plastic over the dirt and weighting the edges along the foundation walls with bricks. I could have also laid insulation on top of the plastic. In my case, because the basement opened into the space, it was a lot more effective to isolate the dirt floor than to attempt to insulate the basement ceiling (the floor of the kitchen).

[Betsy]

The living room portion extends out onto the porch portion, which runs the length of the house. Under it is dirt. Lattice needs replacing, so it is exposed on 2 sides now, but unlikely to get wet, unless a hurricane or major flood comes through.

The d>

[Roger]

I have a 9 by 12 foot bumpout laundry room with four feet of clearance under it, and no side walls under that space. I filled it with 6 inch fibreglas batts, then screwed on 1/4 inch exterior plywood to hold it in place. I didn't vent the area, since there are crosswinds under there, and overhanging roof eaves keep rain and moisture out, but I didnt caulk the seams so some air would get inthere. If there is any chance of rain or moisture getting trapped , you could use zig zagged wire, or chicken wire stapled to the joists, to hold the batts in.

[Betsy]

Thanks. Do you think I should use a vapor barrier up against the floor?

[Tom Miller]

I would if it were my house. The reason is that air infiltration might be a big issue, since floor boards are not exactly air tight. In my old house, drafts and air infiltration are more of a problem in many areas than actual lack of insulation.

Here's my solution: Put a vapor barrier against the floor. Add fiberglass or rigid foam insulation per Roger's suggestion. Then put some sort of sheathing over it -- plywood would work, as Roger says. To hold the insulation between the floor joists until you can put the sheathing over it, use flexible wire holders that fit between the joists, available at home centers and lumber yards (are there still any lumber yards???), or use the cris-crossed wire method.

Since the interior areas do not cover the entire porch, you would either have to block off the edge of the outside wall under the porch to enclose the newly insulated area (I would cut 2 x 6 blocks to put between the joists) or insulate under the entire porch. I think blocking off the area would be easiest and cheapest and most efficient.

Personally, I think you've located a significant source of heat loss that's worth fixing, and good on ya for it. I'm not a contractor or anything (as everyone can probably tell) but just another homeowner who went through this kind of thing around 20 years ago. It's sort of fun. I liked the challenge, and I did save quite a bit on heating bills and improved our living environment.

I would suggest that as soon as practical you find more permanent solutions to some of your "plastic" insulating. For example, I found that putting up plastic storms in a couple of spots every fall got old pretty quick, and it wasn't long before I was skipping it. I just had other things to do, like making a living. Adding real storm windows or replacing the windows made life easier, got the job done permanently, and looked a whole lot better. Just my experience.

[Phil Munro]

This is basically what I did with a small dinning room overhang. I filled the floor joist area with fiberglass (faced toward the floor above) insulation and nailed 1/4 inch exterior grade plywood to hold it and close the area. Then it got a good primer and house paint coat over the bare wood. --Phil

[Betsy]

Thanks for your reply. I think I'll do it just as you described.

Regarding the plastic on windows:

I do have storms, but this is quite an old house (more than 100 yrs) and the windows are just not tight, so I started doing the shrink wrap thing. Then I found these plastic channels that you can apply to the window, put up the plastic sheeting, and snap another piece of plastic into the channel to hold it. It looks really nice, and is a great way to cheaply insulate things that don't have storms, like the window lights around the front door.

Someday when I'm rich I'll get replacement w>

[Tom Miller]

I've seen these and they are easier I'm sure. This house had combination storm windows on most windows already. All I had to do was repair some of the screen portions and fix some of the slides.

Seven larger windows had aluminum storm inserts -- not sure what you call them, but they had frames into which one puts a glass pane on top and a screen on the bottom. In winter, you take out the screen and replace it with a second glass pane. They work great, but it's manual work every fall and spring. But only seven windows.

I hear you. We practically went nutz trying to fit 10 of our windows with Roman blinds. I thought I would have to put my wife in a Home.

We replaced all the windows on the second floor (all the windows were pretty much ruined with moisture, warping, and 50 layers of flaking paint) with aluminum windows with double pane glass. Not as expensive as I thought it might be (but this was 25 years ago). Frankly they do not work as well as the original windows with storms on them, which are now 83 years old.

On third floor we had new, larger windows installed, vinyl-clad wood double pane. They work great and look good. More expensive, naturally.