i live in new england, and i'm insulating a couple of second floor bedrooms, and would appreciate any advice on my proposed plan.
where i'm insulating, there's a small knee wall, then a short section of sloped ceiling (actually the roof rafters), then a section of flat ceiling made from collar ties. instead of insulating the knee wall, i'm insulating the rafter bays from the soffit up past the collar ties, and this is where i have questions.
the rafters are only 2x6, so i had planned on installing kraft-faced R-21 fiberglass insulation in the bays (with the facing towards the living area), then attaching 2" R-10 extruded polystyrene (XPS) foam board (held in place by strapping for the drywall), and taping all foam boards with aluminum tape.
the XPS has a perm rating of 1.1 - 1.4, so i'm not considering this a vapor retarder and don't believe it should present a "double vapor retarder" problem even when combined with the kraft-facing.
i'm assuming the kraft-facing will server as the true vapor retarder. i've read elsewhere on this site that the retarder should follow the "one third, two thirds rule: the VDR has one third of the cavity insulation to its warm side, two thirds to the cold side." so i think i should be all set with the R-21 fiberglass to the cold side and the R-10 XPS to the warm side.
if there are any comments or feedback on my plan - whether to let me know i'm headed in the right direction, or am way off base - it would be much appreciated.
Radiant barrier or foam board to fix cold floor abov...
rigid foam over SOLID wood exterior walls
- 15 Old House Features We Shouldn't Abandon
- 17 Tiny Bathrooms We Love
- 30 Things Everyone Should Know
- 15 Fast Facade Fixes for Instant Curb Appeal
- 9 Expert Furniture Arranging Tips
- 16 Inventive Beds You Can Make Yourself
- 13 Lanterns For Your Porch, Patio, or Garden
- 5 Ways to Repurpose Old Window Screens
- 133 Smart Storage Ideas for the Whole House
- 16 New Ways to Store Kitchen Necessities
- 8 Classic Ways to Make a Small Room Look Big
- 8 DIY Storage Solutions for a Closet-less Room
- 9 Potent Cleaners You Didn't Know You Had
- 12 Hobbit Houses to Make You Consider Moving Underground
- 16 Cool DIY Coffee Tables
- 10 Fall Home Maintenance Musts
- Supersize Your Small Bath With These 8 Pro Tips
- 15 Neat Garage Storage Solutions
- Buy or Build: 15 Desks We Love
- 10 Great DIY Bookshelf Projects
- 5 Minutes Flat: 7 Upgrades You Can Do in Under 300 Seconds
- 10 Creative New Ways to Use Old Bottles
- 10 FREE Storage Hacks
- 10 New Uses for Old Doors
- 7 Ways to Make Your New House Look Old
- Soundproof Your Home with 11 DIYs
- Set the Tone: 8 Colors for an Inviting Dining Room
- 17 Mini Bars to Mix Up Your Home Decor
- 20 Ways to Make a Small Bathroom Big
- 10 Insanely Creative Shelves You Can DIY