Basement stairs issue

Discussion in 'Remodel Forum & Blog' started by lmei007, Feb 4, 2012.

  1. lmei007

    lmei007 Member

    Messages:
    179
    Location:
    Maryland
    I am finishing my basement (1950's house). I want to put insulation on the wall and then frame it. It looks like there is no enough space at the lower end of the stairs (refer to the photos please).

    I have 3 choices, I think. They are followed:

    1. no insulation or less insulation in that area;
    2. make the turnning area even smaller; But it may be too small by cutting another 5.5" from that small area.
    3. make that 90 degree turn one step early (when you go down). That means there will be 3 steps (now is 2 steps) to the basement ground after the 90 degree turn.

    Which way you think is better? do you have a better solution?

    thanks,

    Attached Files:

  2. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Use 2" of spray foam for more value in less depth.
  3. lmei007

    lmei007 Member

    Messages:
    179
    Location:
    Maryland
    I will use 1.5" or 2" foam board. But i have to frame it. So the total will be at least 5.5". Use spray foam will not save much space but more expensive, right? Are you saying the frame is not necessary in this area, and use furring to hold the board? That will will save some space.
  4. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    I said to use spray foam, not foam board.
  5. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,259
    Location:
    Land of Cheese
    You cannot take out a step unless you can re-space all steps without making the riser height greater than 7-3/4". (IRC)

    What you have there now appears to be bead board over furring strips. You could switch to 2" EPS foam board with furring strips topped by drywall, making the wall less than 2" thicker overall.

    For such a small job, the EPS makes the most sense to me.
  6. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,126
    Location:
    NW Ontario, Canada
    Are winders allowed in your area? You could replace the landing and the step above it with three winders if you have the headroom.
  7. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,259
    Location:
    Land of Cheese

    Ok, ya got me. What the heck is a winder?
  8. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,126
    Location:
    NW Ontario, Canada
    Pfft! I'm not trying to wind you up. They are wedge (pie) shape treads that wind their way around.

    [​IMG]
  9. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    If you want to use foam board I suggest XPS over EPS w/ furring strips.
  10. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,259
    Location:
    Land of Cheese
    Yes, that was totally my error. I was thinking extruded polystyrene = EPS, which is not the case.

    XPS XPS XPS, commonly comes in pink or blue, not white.
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,018
    Location:
    Cave Creek, Arizona
    My question would be that since the basement is probably entirely below grade, why are you even insulating it?
  12. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Nothing wrong with a few inches below grade...
  13. lmei007

    lmei007 Member

    Messages:
    179
    Location:
    Maryland
    My question would be that since the basement is probably entirely below grade, why are you even insulating it?

    To reduce/avoid condensation in the summer and heat loss in the winter, I think
  14. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Don't mind him, he lives in 0 humidity land.
  15. Dana

    Dana In the trades

    Messages:
    2,969
    Location:
    01609
    Surely you're joking?

    The average subsoil temps in MA are 45-50F, and the design frost line in eastern MA is 48", and heating design temps are around 0F +/- 5F. (It's slightly warmer for locations 5 miles from salt water, but still only single digits F.) To make it even more fun, eastern MA is a swamp, with a lot of development in areas with high water tables and wet highly-conductive soil. At ~R0.8 a poured concrete foundation represents a HUGE heat loss into that cold-wet/frozen soil. R10 foam insulation for a conditioned basement is easily cost effective here, even R20 has a positive net-present value in a 25 year analysis most of the time.

    But in lower-altitude warmer parts of AZ with design temps well into positive double digits Farenheit, and subsoil temps north of 60F, that would be a valid question.

    If this house has any history of moisture problems in the basement, either wetting of the slab at the base of the wall, or efflorescence on foundation walls, etc. it's better to use more vapor permeable 2" EPS rather than 2" XPS to allow the foundation to dry into the basement. Otherwise the now-higher moisture content of the concrete can wick to top and rot out the foundation sill. Yes, its' a 20% hit in thermal performance, (but still WAY better than the uninsulated wall), but unless you have a metal or membrane capillary break between the concrete & sill, or 4' of exposed above grade wall and 2' overhangs on the eaves for minimal wetting from the exterior, it's better to play it safe. XPS at 2" would be pretty much the limit even in homes without ground moisture issues.
    Last edited: Feb 7, 2012
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