insulating and venting 1 1/2 story home

Old 12-13-04, 12:36 PM
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insulating and venting 1 1/2 story home

I'm new to this site...I previously spent my work hours at but now that project is almost finished.

My wife and I are remodeling our 104 year old 1 1/2 story house in St. Paul, MN. We have 5 knee wall/crawlspace areas, with the accompanying slanted ceilings. The ceilings are all still plaster/lathe or plaster/plasterboard and have varying amounts of insulation in them. The attic has blown in fiberglass that I plan to add to.

When we re-roofed in 2002, we added ridge vent to the main ridge with the intent of adding soffit vent when we could. There is a dormer (not sure if this is the correct term) with these knee walls on another portion of the roof that we didn't vent, because there is no attic above it, it's plaster up to the peak (about 7' tall).

We have removed the plaster and lathe from the end walls with the intent of insulating them, and we have also removed all of the insulation from the crawlspace behind the knee walls.

Here are our questions:

We would like to insulate, vent and have a proper vapor barrier the slanted ceiling/knee wall area in such a way that the space is still usable for storage. I have read the DOE's flyer on this, but it doesn't really tell me how we could install such venting and insulation. The amount of nails sticking through the roof decking is amazing, and there is still quite a bit of insulation stuck up behind the plaster. I could with some sort of hook remove all of the old insulation, and then attempt to slide rigid insulation in behind it, but is that a bad idea? Is there a way that people have made this work?

We would really prefer to avoid removing the slanted ceilings. The plaster is still in decent shape for the most part.

I also wanted to ask a little about the painted on form of vapor barrier. Does it work? I'm always a little suspicious about anything that sounds like a cure-in-a-can, but we want to do something.

Thanks for any input.

Old 12-14-04, 08:01 AM
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This site illustrates a Drip Edge Vent. There are a variety of ways to accomplish this type of venting and products. The FASCIA BOARD is the board that both the bottom of the drip edge vent and gutter are nailed to. The following is an example of building one yourself.

DRIP EDGE VENTS are installed under your first row of shingles and are usually attached to the fascia boards and the roof underlayment. There are a variety of ways of accomplishing this type of vents. I personally prefer the built out type. I remove the gutters and fascia boards to expose the rafter tails. I nail a 1/4 inch material to the rafter tails making sure is at least an inch gap between the underlayment and this 1/4 inch material. Then I nail 1x2 wood slats onto the 1/4-inch material over each rafter tail. Nail the fascia boards to the slats, install a drip edge to make up for the build out and install the gutters.

This site illustrates the different ways to insulate the area you are concerned with. It is in the last section known as KNEE WALLS.

This site discusses VAPOR BARRIERS. If you read this fact sheet, you will see that you do not need a vapor barrier in your application. The reason for this is the several layers of paint already on the walls and ceiling. This qualifies as a vapor barrier because the Perm Rating is probably lower than 1.

Insulating the SLANT WALL and providing enough VENTILATION. My personal favorite for this application is an unfaced R-13, staple gun, Styrofoam baffles, fishing pole and line. First measure the distance from the knee wall to the ceiling. You baffles have to longer than this distance. The fishing pole does not have to but should be close to this length. You can do this either from above the ceiling area or knee wall area, it does not matter and are both done the same way. Cut the baffle at least two feet longer than the length of the slant wall and the insulation at least one foot longer.

Then attach the fishing line to the top guide ring of the fishing pole. Take a measured and the cut baffle and put it between the pole and the line. At the other end of the pole temporary attach the line to the last guide hole. What this does is allow you to move the baffle while it is in the slant wall cavity. In the event that it should get hung up on a nail or something. Slide the baffle into the cavity until less than a foot of baffle extends past either the ceiling or knee wall depending where you are. Untie the line at the bottom of the pole and pull the pole back until both the pole and line are with you. Then staple the baffle to the underside of the roof sheathing.

You do the same with the insulation, fishing pole and line. You might find it difficult to get passed the uneven surface of the plaster inside the cavity. You can try pushing the pole up against the baffle to get over this surface. If it comes to that, let me know, I will tell you a way of doing it. Also, if you intend to insulate all the way down to the eaves, then you have to use faced insulation.
Old 12-14-04, 11:08 AM
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I'm anxious to try these ideas. The house is getting dry (humidity) and the furnace is running constantly with all of the insulation stripped out.

I hadn't thought about using a fishing pole to get the baffles and insulation back there. That's a great idea.

There are several rafters that are two peices scabbed onto each other, I assume a 2 peice baffle, one from the top and one from the bottom should work?

I want to really get a good look at the links you provided and then follow up with any questions.

Thanks for answering my post.

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