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Community and Q&A

Alternatives to Foam

homedesign | Posted in Energy Efficiency and Durability on

My North Texas Climate (hot/mixed humid) is not-so-extreme.
But we WASTE a lot of Energy and money trying to stay comfortable.
Even more than folks in the North-East.

The standard Low Energy Enclosure here is almost always achieved with spray foam or sometimes with a combination of spray foam and rigid foam.

I can design structures to around a HERS 50 with these products plus some “gooey-stuff”

If I want to go below HERS 50… I quickly hit the dreaded diminishing return.
Not because R-value “stops working” but because the “COST” of foam is TOO darn high.

This is what sent me on the path for Alternatives to Foam.

Martin will attach a couple of drawings and then I will be asking for suggestions and feedback.

I will provide more description after the drawings are posted.

I understand the Priorities for designing in a Hot Climate
Proper shading and window orientation …
I would prefer not to go into those aspects in this thread.
I would rather focus on Good airtightness, Reduction of thermal bridging and low cost/high R-value.

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  1. Riversong | | #1

    A good alternative to foamed plastics is solid plastic. Get rid of those pesky air bubbles and toxic foaming agents and use the real McCoy.

    OK, I'll wait for more details before responding...

  2. RaterPaul | | #2

    flash & batt is more economical ... I guess the jury is still out on that

  3. GBA Editor
    Martin Holladay | | #3

    John Brooks:

  4. homedesign | | #4

    Well it is hard to see the airtightness concept at this scale
    I will send a zoomed in pdf (might be Tuesday)
    It is a variation on a BSC detail that is used where partitions meet interior walls.
    It includes plywood to bridge over the the top plate.

    I am wondering if "airstop" tape could be used to tie the ceiling drywall to the plywood strips.
    The tape would not be subjected to extreme temperature swing so my thinking is that it will be more reliable... and maybe less fussy than using sealants.

  5. Riversong | | #5

    What the heck are we looking at below the ceiling?

    This demands a detailed description.

  6. homedesign | | #6

    that is a partion wall beyond
    I will add mucho notes and a detailed description Tuesday

    Why it was perfectly obvious to me ;---)
    much like the narrative descriptions without the images
    looks like we need both

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