Attic/crawl space insulation question

[mundamanu]

I was just poking around in the attic and two crawl spaces since I have noticed that it has gotten a little chilly on the second floor during our fall cold snaps.

I discovered that all of the attic and crawl spaces have insulated floors. The main attic has blown insulation about six inches deep. The two crawl spaces have rolled insulation about six inches thick and covered with plywood (not 100% coverage, but significant). There is no insulation at all against the roof. As I understand insulation, having the floors insulated and not the roof is fine since all of the heat is trapped below the attic and crawl spaces (and in some ways this is better since that way you are not heating the attic/crawl spaces). Access to the attic is through a small square hole in the ceiling covered by an insulated cover. Access to each of the two crawl spaces, however, is through a full-sized, uninsulated, two-inch thick wood door. It seems pretty clear to me that the cold air is coming through the uninsulated doors (the house-side walls of the crawl space are also insulated).

So, onto my question. Would a reasonable solution to this problem be to make an insulated wooden frame six inches thick and backed with plywood that fits snugly in the door frame on the crawl space side? The frame can be thicker than six inches, if necessary, I would just need to build a support off of the inside of the existing door-frame to hold it in place.

If my idea is not a good idea, what is a good idea?

Thanks in advance.

 

[MaineGuy]

Yes, you are correct, the door needs to be insulated as it is part of the wall. The frame idea is what I used in my house and works pretty well. You don't want the warm air passing through into the cold attic space. Attic space should be as close to outside temp as possible. Another thing to check is any openings through the floor, ie. vent stacks and chimneys. Make sure that the space around them is sealed and no air is traveling from lower levels. Of course the second part of the attic equation is ventilation. Somewhat more difficult than insulation.

 

[RobS]

We have a walk-up attic with a standard, interior door at the bottom of the stairs. The attic is uninsulated. I simply put weatherstrip (self-stick foam strips) around to seal the jamb and cut a piece of 2" rigid styrofoam to fit the attic side of the door. A couple of long wood screws with big washers hold it in place. It's probably not enough insulation but I need to be able to get through the doorway when the door is open /forums/images/graemlins/smile.gif

 

[bczoom]

Instead of building a wooden frame, would what Rob is using work for you? (polyisocynurate insulation panels) Thinner and less mess.

1" is R-7.2 A couple stacked up will get you to the same as 6" insulation. If you leave a 1" gap between the panels will also increase the R factor.

 

[CtRick]

</font><font color="blue" class="small">( The main attic has blown insulation about six inches deep. The two crawl spaces have rolled insulation about six inches thick and covered with plywood (not 100% coverage, but significant). )</font>

This has nothing to do with your question but as a firefighter I would suggest that you remove that plywood if it is not necessary. During a major fire, firefighters will cut a hole in the roof almost directly above the fire and break through the ceiling from above. This effectively creates a chimney effect that draws all the super heated fire gasses out of the structure. Plywood floors in attics and crawl spaces hinder these efforts to vent the fire up and out of a home in a controlled manner. The attached photo shows fire coming out of a hole that we cut. Just a thought /forums/images/graemlins/laugh.gif.

Rick

 

[mundamanu]

Thank you all for the suggestions. I hadn't thought about the insulated panels. They are a much easier option than what I was considering.

 

[SPIKER]

CTRICK: glad that is not MY house! /forums/images/graemlins/frown.gif

Blown insulation is pretty good but also can create a mess if it gets where it shouldn't the upper roof should not be insulated to keep roofing cool durring summer and like others said venting is an importaint inssue..

/forums/images/graemlins/crazy.gif

MarkM

 

[beenthere]

Thanks for that bit of wisdom, as to why the hole was cut above the fire. I had the notion that it was to burn the house down quicker, which it seems to do. But your reason makes more sense now that you mention it. I've never heard that one should avoid putting in an attic floor of plywood for that reason though.

 

[slowrev]

Not sure I would want my house put out after it got to that stage anyway......

 

[CtRick]

Not to hi-jack this thread but you'd be surprised at how well a correctly placed vent hole can minimize damage to the structure. In the case of this particular photo; the fire started in a basement and self-vented out a window. It then burned up the outside of the house and burned through the soffit vents into the attic. Damage to the main living space of the home was minimal. It always amazes me how people do so much to protect their homes from water, both inside and out, but not do much to make their homes safer from fire. Like having bedrooms that cannot be easily reached by ladders because of landscaping or the lay of the land. Or having so much clutter around their furnace that they are almost impossible to get to. Don't get me started about candles or extension cords or smoking in bed... /forums/images/graemlins/blush.gif. Again, sorry to hi-jack this thread.

Rick
(whose daughter sleeps in the most accessible bedroom in the house)