# Attic insulation / venting of 60s era house



## Gary in WA (Mar 11, 2009)

Be careful using blown-in on the low-slope section without good air movement above it; http://www.buildingscience.com/docu...archterm=attic+fiberglass+batts+in+flat+attic

Find the closest big City below the map for your Zone: http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_11_par002.htm

Find the insulation requirements needed: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_11_sec002.htm

Furr down the rafters on the sloped section to meet minimum or add inside rigid foamboard. Air-seal the attic floor and the drywall. Block air movement under the knee wall. Add a housewrap over the new knee wall insulation on attic side to prevent wind-washing. Add baffles of f.b to create an air channel (no insulation touches roof sheathing); http://www.buildingscience.com/documents/published-articles/pa-crash-course-in-roof-venting

Figure NFVA: http://www.airvent.com/homeowner/products/intakeSoffit-specs.shtml

The 3" soffit vents require 2 holes for getting the minimum 1/150 or 9sq.in. per foot; https://ventmastersstore.com/shop/3-round-open-screen-vent-black-p-175.html

Gary
PS. welcome to the forums!


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## Chokingdogs (Oct 27, 2012)

Thanks for the reply, and the welcome. I cannot believe I never found this site in the past, lots of great info here, and would have saved me many many instances of measuring once and cutting four times....LOL

The closest "big" cities south are, basically, Bal'mer, Frederick, and Hagerstown. All three of which are in the next zone down. Harrisburg, about 40 miles north, would that be a better measuring stick for R insulation requirements as it's in the same zone? I figure it wont hurt to go a little more than what's "required"?

I'm going to try and attach my best attempt at a MS Paint Picasso of what I have to work with. It's only a rendering of the second floor cross section, I didn't bother with the first floor. My biggest question is what to do from point A to point B - rafter vents, then a layer of paper backed insulation over top? The area marked "attic / storage", while not conditioned, is accessible off the upstairs hallway by a standard 32" X 6 1/2" doorway, and it runs from one end of the house to the other. The area shaded blue I have no idea what's there, and below that is conditioned living space.

Thanks again for any advice / guidance. I've got another, related question, that I'll post next as to not cross contaminate both situations.


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## Chokingdogs (Oct 27, 2012)

2nd related insulation question.

House has a semi-detached garage with "living space" over it. Was used for storage, then 20 some odd years ago converted. It's accessed off the end bedroom through a standard doorway and it has retrofitted electric baseboard heat. We used to call it The Microwave, due to the fact in the summer you could put a slab of prime rib on a plate in there and after a couple hours....you'd have some nice roast beef.

Currently has rafter insulation, but I have no idea on what's behind the knee walls and under the subfloor. All I know is, in the summer it's bloody hot and in the winter one could make popsicles. There's a small peak - the "attic" - in which there's three or four bricks left out on the end to vent it. So no true gable vent, just a few holes. I plan to yank out what's currently there and drywall the whole joint. If rafters are 2X4s, should they be furred down to allow for rafter vents+insulation, or should I just insulate w/o those vents? No living space below, just the garage, but I do plan to heat that with one of those ceiling mounted electric heaters...like this - 

http://www.grainger.com/Grainger/DAYTON-Electric-Utility-Heater-3UG73


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## Gary in WA (Mar 11, 2009)

The rafter baffles only need to be used near the soffit intake vents, unless a full cathedral ceiling. You need to establish where you want/need the insulation barrier (through the smaller attics). If going for for a vented attic, be serious about it; http://www.buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation?full_view=1

Gary


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## Chokingdogs (Oct 27, 2012)

Thanks. I'm getting quite serious about venting/properly insulating the whole shebang, especially after poking around it again this past weekend.

The "insulation", and I use that term loosely, visible in the attic/storage space in the drawing above, is this stuff:

Balsam Wool - says right on it. Made by the Wood Conversion Company, with an "average applied thickness of 1 inch", and "meets commercial standards 160-49". 

The stuff is literally two pieces of black paper surrounding about an inch and a half thick mess of ground up whatever. The stuff is stapled between the rafters, with an air gap between it and the roof sheathing, from the front soffit all the way up to the attic space. I have no idea what's beneath it, the area I shaded blue above, on the ceiling above the first floor living space. That space is probably a good 8 feet deep and runs the entire length of the main part of the house, and for all I know, there's nothing.

That same stuff is what's laid between the joists in the attic, directly on top of the second floor ceiling gypsum, and why it only looked like an inch of insulation initially, because that's exactly what it is, LOL.

The roof does in fact have a ridge vent, a brighter flashlight shed more light on the subject, and viola....there one was. It's the "brillo-pad style" ridge vent.

So, plan now is - rip out knee wall in attic/storage space and existing rafter insulation, add rafter vents from soffit up to true attic, add soffit vents on front of house and baffles, then blow in cellulose to proper R value in that area. Close up knee wall.

For the actual attic, same thing sort of, rafter vents at soffit on rear of house, baffles, then blow in cellulose to proper R value in attic. There is a chimney going through the middle of the attic, it's cinderblock, and that chimney handles the fireplace in the living room below as well as a fireplace in the basement, along with the exhaust for a gas hot water heater and the gas fired boiler. Does that pose an issue with blowing in cellulose - a barrier of some sort needed, or can it be blown right against the blocks without concern?

Thanks


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## Gary in WA (Mar 11, 2009)

You need a metal barrier around the chimney, treat it same as a flue pipe. pp.6: http://www.energystar.gov/ia/partners/publications/pubdocs/DIY_Guide_May_2008.pdf

The brillo pad ridge vents are the worst, make sure it is not compressed at the hold-down fasteners; http://www.inspectapedia.com/interiors/atticcond10.htm

The baffled ones are best: http://www.oikos.com/esb/30/atticvent.html

http://www.youtube.com/watch?v=rE6fyWHfTXc

Gary


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