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Wall insulation

8 years ago
last modified: 8 years ago

Finding out builders in central Florida are only 'standard builds' to Fl minimum of 2012??- date may be incorrect. I prefer R30 walls and R40. Northern Wyoming home was R60. Both very cold winters and 103+ summers, although short. Have followed closed cell foam since it came out but it seems that it has not performed as well as expected particularly in humid/wet climates. I do not see a easy to put R30 batts in a concrete block house even with 2x4 or even a 2x6. Even adding 2x4 or 2x6 frame inside concrete block is a waste of $$. Normally 1x3 strips interior of block as we have now. (1967 build). There will not be any exterior insulation panels as we want the look of midcentury 60's concrete block exposed (painted). Is there a product I am missing. Wife has asthma. Thx

Comments (15)

  • 8 years ago

    Thanks David Cary! Maybe I wrote wrong word- didn't look back yet. The R60 was in the ceiling. I do want more than code in walls. We had R15 in Sarasota in new build (stick frame) in 1990. It did not feel like enough to us. The south had 2' overhang. Very good windows- if I remember correctly Manatee County?? had very stringent codes for that time. West also. North had full length insulated ceiling over 8' deep porch. Being primarily from very cold country we (HATE!!) the hot weather here. Insulating against heat is just as important as against cold. Definately want R30 in walls. R30 in ceiling is minimal Fl code. Minimal is not enough. I appreciate your thoughts but from experience of living throughout the country over many years we know what we want to make us comfortable. My question was 'how would be the best way to achieve this with a new concrete built home. (Do not want SIPS). THANKS ALL!

  • 8 years ago

    R30 in a florida wall is going to cost you because absolutely no one does it. The money would be better spent on solar panels.

    The delta T in Fl is so small that that level of R value is a complete waste.

    It would truly be a significant waste of resources to build that wall. Isolate air movement which is different.

    80 degrees outside and 70 degrees inside is just not that much of an issue.

  • PRO
    8 years ago

    I'd look elsewhere for this info.

    Green Building Adviser (greenbuildingadvisor.com)

    Building Science Corporation (buildingscience.com)

    Ed(Edwina) and Stephen Ci thanked PPF.
  • PRO
    8 years ago

    Find a local energy consultant. There is much more going on here than just insulation. An energy consultant can advise you on the best insulation package, what kind of windows (U-values and Solar Gain) and the best HVAC system. The consultant can help you with orientation, natural ventilation and shading strategies as well.

    Ed(Edwina) and Stephen Ci thanked Summit Studio Architects
  • 8 years ago

    ICF walls (R-24 or so) are a good choice for FL because of their high wind resistance. They are also very air tight- important to get your insulation to perform up to its rating. When you talk about stick framing, the heat transfer through the studs can de-rate the structure as much as 25%. Doesn't leave you much when you start with R-13. ICF doesn't have that problem. It is more expensive, though.

    Ed(Edwina) and Stephen Ci thanked mushcreek
  • 8 years ago
    last modified: 8 years ago

    Yes, ICF makes a lot of sense. It is probably the best way in Fl to get what you want. It costs money but at least it is done in Fl. Definitely a thick wall which adds some to cost - ie foundation and roof need to be bigger. Windows need to be relatively bigger since they are shaded some by the thick wall. But a great idea given your wants.

    I will say that many people swear by ICF and make rather outlandish and unsubstantiated claims. That always leaves a bad taste in my mouth. But it is definitely a decent product just not as amazing as some people think it is.

    Ed(Edwina) and Stephen Ci thanked David Cary
  • PRO
    8 years ago

    David Cary makes a great point about the difference between inside and outside temperature (Delta T). In Northern Minnesota where it can be -20ºF or colder the Delta T can be 90-100º making insulation and great windows and doors critical. When the Delta T is cooling from 90 outside to 70 inside insulation becomes a lot less important. You may be much better off with a more efficient HVAC system. These are all questions a good energy rater can model for you and give you realistic payback periods. All your systems need to work together to obtain the optimum result.




    Ed(Edwina) and Stephen Ci thanked Summit Studio Architects
  • 8 years ago
    last modified: 8 years ago

    You may be much better off with a more efficient HVAC system.

    That and also orienting the house to best take advantage of passive solar cooling and also not making the house deeper than one or two rooms deep.

    I'm in SW FL and I found that even in the heat of the summer this past year without AC, my house was relatively cool compared to the outside temps because of cross breezes and the orientation of the house. This was before the AC was working in the house.

    Ed(Edwina) and Stephen Ci thanked cpartist
  • 8 years ago

    We lived in central FL for 30 years. Temperature extremes can be greater than folks realize, and HVAC costs can be huge in a poorly designed/built house. Although our coastal community never officially saw 100 degrees, it was consistently in the mid 90's for months at a time. The coldest we saw was 19 F. Our house was uninsulated concrete block, single pane windows, beaten down R-19 in the attic, and lots of air leaks. Power bills of $300 a month happened from time to time. They did other dumb stuff, such as putting the HVAC duct work in the uninsulated attic.

    Living in a properly designed and insulated house has been a revelation. We are in upstate SC now, with much wider temperature swings. This is where ICF really shines. We have small mini-split (ductless) HVAC units, as our house is too efficient for a traditional central system. Energy bills are comically small. Insulation, air sealing, low-E windows, large roof overhangs, careful lot orientation, particularly to block west sun, and high efficiency HVAC equipment all make a big difference in power bills and overall comfort.

    Ed(Edwina) and Stephen Ci thanked mushcreek
  • 8 years ago

    What mushcreek said too.

    We do have low e windows, large roof overhangs (32"), careful lot orientation, and a variable speed AC unit.

  • 8 years ago

    Standard by me is 2x6 exterior walls, which gives you a ~6" cavity, and 6" fiberglass is typically R-19. Cramming more fiberglass into a 6" space does not yield higher R-value. R-30 glass would be >9" thick (varies by manufacturer). You'd have to either do spray foam (diminishing return, not really feasible here) or rigid board on the outside.

    Diminishing return is the big point. There are also theories that you don't want to live in an air-tight box - see germs/bacteria/mold/etc. If you say "I'll vent with my windows then" then what's the point of the insulation.

    You'd be better concentrating on solar gain, shade, roof insulation, HVAC efficiencies, and those line of theories

    Ed(Edwina) and Stephen Ci thanked sprink1es
  • 8 years ago

    Actually, "cramming" does yield a slightly higher R value. So if you have some odd sized bays "cramming" all your scraps into them is beneficial, more R value and less waste.

    http://www2.owenscorning.com/literature/pdfs/10017857%20Building%20Insul%20Compressed%20R-Value%20Chart%20Tech%20Bulletin.pdf

    Ed(Edwina) and Stephen Ci thanked ksc36
  • 8 years ago

    To a point but it's exponentially less effective. The air pockets in the glass do the work. Then when you cram it, it breathes less and there's negatives to that. Technically you're right but I don't really see it done in practice

    Ed(Edwina) and Stephen Ci thanked sprink1es
  • 8 years ago

    "Breathing" went out in the 90's. That's why fiberglass insulation is on it's way out. It's the worst performing "legal" insulation out there.

    Ed(Edwina) and Stephen Ci thanked ksc36