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Insulating kneewall/roof in Cape Cod; NO SOFFETS, please help

Insulating kneewall/roof in Cape Cod; NO SOFFETS, please help


  #1  
Old 01-16-13, 08:51 AM
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Insulating kneewall/roof in Cape Cod; NO SOFFETS, please help

I'm posting here because every time I ask any local contractor/artisan all I get is conflicting answers, and every time I have work done the next person says it was a bad thing to do.

I'm wondering how BEST to insulate the kneewall/cubby space behind the kneewall in what I presume is our Cape Cod style house. Below my questions here are pictures and some CRITICAL (I believe) information that may influence your advice. Please see this info and look at pictures before answering; there are common answers to these issues, but the details at my particular house would seem to change things.

1) Should I remove the nasty original tarpaper/orange stuff currently installed against roof? It looks like it's bowed downward, but I don't know if this is from age or on purpose to allow air flow behind it (but there are no soffit vents).

2) If I remove it, should I put new insulation up? And if so, which side faces inward (towards room); the paper or the pink?

3) Should I Tyvek over the insulation facing inward, or should I Tyvek the flat space between rafters on the roof part?

4) Is it a BAD idea to insluate the kneewall part (other side from roof) space? If not, which part faces the room, the paper or pink? Should I Tyvek over the insulation, making a flat sheet along the 2x4's?

5) On one side I have a doorway access to the atticy-space beind kneewals. On the other side I have little cubby doors where the dormers are to access the space; do I treat one side different than the other?

6) There is no wood blocking the space between the floor joists on this floor; I've read there's supposed to be something blocking this area, like right under the kneewall; there is nothing there; when I put the camera down there, the picture shows space all the way through to the other wall, I believe. Should I put something down there? I don't want to tear the floor up. Should I just blow insulation down into all these spaces between joists, first from one side and then the other, until I've filled (as much as possible) all this space?

Some (possibly) important info:

A) There are no soffits; the roof stops right at the top of the external walls of the house.

B) I've been told there is nothing to bring in air from the bottom of the roof, to flow from botom of roof to top. I went up on the outside and looked, and I don't see anything either; those little vents down near the bottom few rows of shingles were NOT put in, so again: I believe there is no method for air to come in at bottom of roof.

C) When we got a new roof installed, they cut ridge vents in (at peak of roof), and did not cover the gable vents. They said since there was nothing at the bottom of the roof to allow air flow, there was no harm in leaving gables open.

D) We did have a pretty serious ice damming problem BEFORE we got the new roof, and it was MUCH colder/hotter (depending on season) upstairs than downstairs. The new roof/ridge vents seemd to ALEVIATE (not solve completely) the ice damming AND the temp. disparity.

E) There was NO insulation in the downstairs walls; we recently had blown in insulation done in all exterior walls. This seemed to make it colder/hotter (depending on season) upstairs again, but not as bad as before we got the roof. I wonder if these walls were left non-insulated, and some old building technique allowed air inside the walls to flow up and along roof, instead of soffit/roof vents.

F) There is no insulation on roof part in the actual attic above the kneewalla space; the old tarpaper/orange stuff stops, but I don't kno EXACTLY where.

G) In the actual attic above all this, there is just the pink fiberglass insulation laid down along top of ceiling joists, where that orangy stuff rns along the canyon between joists. The fiberlass is just paid down, not nailed or "installed."

The pictures show the kneewall space, including where the old black tarpaper/orange stuff meets the floor of the knewall space, and also looking up to where it goes up into the top. The pictures are named what they are looking at. I have many more pics, so if you'd like more or more info, please let me know.

Ay help with this would be really appreciated; I have come to despair of getting any really good answers from local people; they have said some really ridiculous stuff that people on here have confirmed are very bad and unknowledgable info. I would really appreciate your help/advice with this.

Thanks for reading, and for any help.
 
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  #2  
Old 01-16-13, 08:45 PM
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You should insulate next to the conditioned space. That is, on the top of the first floor ceiling outside the kneewalls, on the kneewalls, on the sloped ceiling/wall area above the kneewalls, and on the flat ceiling above the second floor. There should be no insulation touching the roof, and there should be a 2" gap between the insulation and the underside of the roof, everywhere.

You do not need any insulation under the upstairs floor, unless you want it for sound attenuation. It will serve no useful purpose for energy conservation.

There should be a vapor barrier installed between the insulation and the conditioned space.

I don't understand how Tyvek or any other housewrap might be useful in an attic.

Never say never!

There are several ways to add roof-edge intake vents to your house. One member did that by removing the uppermost trim piece on the wall, below the roof, and cutting a slot that he protected with screening before installing new trim with a gap between it ans the roof. His house, however, had a broad overhang, so that is probably not a solution that will work for you - just an example of an innovative solution.

That said, there are a number of commercial products that should do what you need. I found two examples with a quick search; there are others:

The Edge™ Vent from Air Vent and the SmartVent from DCI Products. I would contact my roofer to have one of these, or one of the other similar products, installed, and to have the gable vents sealed. The flow from those vents will interfere with edge-to-ridge flow.
 
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Old 01-17-13, 04:59 AM
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Thanks very much for your response, NashKat.

When you say "on the sloped ceiling/wall area above the kneewalls," do you mean I should tear out the insulation that's already on the underside of the roof, but nly up to where it's above the kneewalls, and leave that stuff in (or replace it)?

Would I be doing harm by REPLACING the insulation that already exists? Would things get better if I just REMOVED it from the underside of the roof where its NOT above the kneewall?

Also, I notice (seen in picture) that the tarpaper stuff seems to flatten out as it goes up into the ceiling, like it's not just one angle all the way up, it appears to flatten out. Is there some trick I need to replace/install up there, like do I need to do it fromm the attic space above (not sure I'd even have access), or is there some plate/beam/[insert official terms of how wood comes together at top floor ceiling/attic floor where they meat the roof] that I tuck into, or staple over, etc.?

Thanks again, very much, for your assistance.
 
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Old 01-17-13, 07:44 PM
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When you say "on the sloped ceiling/wall area above the kneewalls," do you mean I should tear out the insulation that's already on the underside of the roof, but nly up to where it's above the kneewalls, and leave that stuff in (or replace it)?
I thought I was being clear by saying
Originally Posted by Nashkat1
You should insulate next to the conditioned space.
and then describing each area to be insulated, in order, from the top of the first-floor wall to the roof peak. I see that I could have been clearer, and I regret that I wasn't.

By "the sloped ceiling/wall area above the kneewalls," I meant that area where the ceiling inside the room follows the slope of the roof, from the top of a kneewall to the outer edge of the flat center ceiling.

I have no idea what that stuff on the underside of your roof is, nor why it was installed. Possibly it was an ill-conceived attempt to mitigate condensation buildup. Regardless,
Originally Posted by Nashkat1
There should be no insulation touching the roof, and there should be a 2" gap between the insulation and the underside of the roof, everywhere.
The only installed material that should touch the underside of the roof should be air-flow baffles, if you need those, under the roof-edge intake vents and between the insulation and the roof in the sloped areas.

Should I remove the nasty original tarpaper/orange stuff currently installed against roof?
Yes.

Would things get better if I just REMOVED it from the underside of the roof where its NOT above the kneewall?
While there are no guarantees, they certainly should.

do I need to do it fromm the attic space above (not sure I'd even have access), or is there some plate/beam/[insert official terms of how wood comes together at top floor ceiling/attic floor where they meat the roof] that I tuck into, or staple over, etc.?
I don't know how your second-story room is framed, and can't see this detail in your pictures. The most common method is that the flat ceiling is attached to the bottom of collar ties that double as the ceiling joists, and the rafter bays are left open. This is what you need in order to maintain continuous airflow from the reef edge to the peak, so I hope that is how yours is done.

That flat area above the second-floor ceiling is the most important area to insulate, so you need to create access to it. Too bad you don't have big triangular vents in your gable ends. But this description makes it sound like you have access now:
In the actual attic above all this, there is just the pink fiberglass insulation laid down along top of ceiling joists, where that orangy stuff rns along the canyon between joists.
The next most important area is the top of the first-floor ceiling, between the kneewalls and the roof edge. The third is the sloped areas between the kneewalls and the second-story ceiling. Insulating the backs of the kneewalls should not be overlooked, but that is where you will install the lowest R-value material. This is not to say that you will install in that order. You might or might not. It's just to say that those four ares, in that order, will provide different levels of return on investment, from highest to lowest.

To determine the insulation R-value and other improvements that will give you the best return, and to get an estimate of the savings, you should enter the specific information for your house in the ZIP-Code Insulation Program, or a similar calculator.

Once you have that information, we can talk more about products and methods to get you there.

BTW, you said that
The pictures are named what they are looking at.
but I didn't see any names on them. Am I missing something?
 
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Old 02-15-13, 11:22 AM
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similar problem

I am facing a similar situation in my house. The house was built in 1924 and has no insulation in the knee walls or sloping and flat ceiling areas of the attic bedroom. It is a 2 and half story house. It has a new roof with a ridge vent and soffit vents.

We want to fix up the attic space to be a good looking, useable, comfortable bedroom. But, we do not want to cause any vapor damage to a very nice historic home by improperly insulating it. The original plaster walls are intact, but not in good shape. We have been advised against removing the old plaster and lath.

We had a contractor come in who is recommending putting a vapor barrier over the old plastered ceiling and then putting up new 1/2 in dry wall directly over that. Then he plans to place air baffles in the sloping area of the ceiling and blow fiberglass insulation into the ceiling area.

On the interior side of the knee walls he is planning to cover the original plaster with vapor barrier and then install a thinner drywall (1/4 in). On the exterior side of the knee walls he plans to create pockets between the studs with luan board so he can blow insulation into the pockets while protecting people from contact with fiberglass who will be entering these storage areas.

Does any of this sound like a good idea? or bad one? Would very much appreciate your input.
 
 

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