Help Insulating Saltbox attic

[RISurfer20]

I am adding insulation to a salt box cape. I am located in Rhode Island. I have 2 seperate attic areas. The first area is above the bedroom which is easy to insulate. The second area is an area through one of the bedroom and runs full length front side of the house. This crawl space is insulated with R19. The insulation is along the rafters. During winter this space is cold and leaks into the bedroom. The knee wall door is insulated to R30. I would like to improve insulation in this area. My question is should I insulate the knee walls in this space and or floor with unfaced insulation? If I do insulate this area will I run into ventilation problems? Any help would be appreciated. Thanks.

 

[RISurfer20]

I have duct work in this area. My set up is the same as picture 2 diagram bottom right.

 

[RISurfer20]

Sorry I mean picture one bottom right. That is my current set up.

 

[SolarAndWood]

If you have uninsulated ductwork in the crawl space, I would run foam board across the face of the rafters and tape the seams.

 

[RISurfer20]

Thanks for the replys. Should I insulate the rafters, the knee wall and the floor or just insulate the rafters?

 

[Gooserider]

Might also be worth taking a look at your access door to the area... In our house we have a similar setup on one of our FIVE different attic spaces - and the access was just a plywood panel. I glued a sheet of 2" foam to the back side of the panel, and shaved it to fit by the iterative "try and put it in, then shave where it hits" method, and added some weatherstripping around the edges. It isn't perfect, but it made a big difference.

Gooserider

 

[billb3]

Thanks for the replys. Should I insulate the rafters, the knee wall and the floor or just insulate the rafters?

Your first post says the rafters are already insulated.

The pic on the left shows the two ways to insulate a kneewall area.
Where you've got ductwork you want to protect from cold and condensation you should be better doing the system on the lbottom left.

No ?

 

[peakbagger]

Whatever you do, make sure that you retain contiunous ventilation from the soffits up past the knee wall and up to the ridge vent, saltboxes are infamous for ice damming where the crawl space is colder than the space above the finished ceiling. This can cause a lot of damage in a short period of time if the weather conditions are right after a heavy snowstorm. I have insulation in the floor and the knee wall is heavilly insulated with nothing on the roof in the crawl space area, with proper vents running from below the knee wall to above the finished celing. I have heavy snow build up most winters and to date have never seen any damming occur. By the way, also make sure that someone didnt take a short cut and run the bathroom vent exhaust up into the crawl space or the soffit, that can raise heck when you try to tighten up this area.

 

[RISurfer20]

Thanks for the replys. Local company states I should insulate the rafters, knee wall and floor with R30. Rafters are 2x4's so I figure I will just keep the R19 on the rafters and maybe add an additonal vapor barrier and R30 the rest. There is decent ventilation. Soffits are no blocked. I will have to keep in mind not to block the flow of air when I insulate the knee wall.


billb3
With some research I have learned that insulating the rafters is a better call if you have duct work on the attic crawl space floor.

Peakbagger
I have had some ice dams in the past nothing major. Seems like all the houses in the neighborhood have the same problem in the winter.