non-toxic, expanding foam sealer?

Discussion in 'Designing, building, making and powering your life' started by songbird, Nov 17, 2014.

  1. songbird

    songbird Senior Member

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    in another thread:

    https://forums.permaculturenews.org/showthread.php?18452-Hempcrete

    TLP mentions sealing foams being toxic and other foam products being
    also questionable.

    as this is not a purely hempcrete question i think it worth breaking this
    out into another topic and that being:

    are there any expanding foam alternatives that will seal up cracks as
    well as the foam sealers?

    specifically, here, i have used the foam sealing spray cans because
    they do expand into cracks that i cannot otherwise reach. i have more
    to do eventually...

    foam boards i don't use, but i would be interested to hear of anyone
    who has tried other methods of foam generation and filling of a space
    with a relatively inert material which will not settle, rot or crack and has
    a high R value...

    i think that perlite is a fantastic material in many ways, but the energy
    involved in making it or the expense of sourcing it doesn't make it a
    viable and cheap alternative.
     
  2. Gonhar

    Gonhar Junior Member

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  3. songbird

    songbird Senior Member

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    unfortunately, not available in small quantities that i can use off the shelf. and i don't think it expands much, but perhaps that could be fixed with some experimentation. : )
     
  4. pebble

    pebble Junior Member

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    can you give an example of what you are trying to seal?
     
  5. songbird

    songbird Senior Member

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    sure pebble, : )

    we have siding on this house which gets gaps and cracks in it. also behind it in places is a gap of the width of the siding. initially, the bottom the siding was left open initially and that meant that mice could climb up in there and have an easy nesting site. when i first stayed here i could not sleep for all the noise in the walls and trapped several hundred mice. oh, and they had been chewing some of the wires in the walls too. quite a mess.

    after getting the mice out of the walls Ma put split stone and cement along the bottom but did not put down a proper footing or tie it in right with the foundation wall. i tried to get her to change what she was doing, but she didn't. which means with our frost/thaw cycles that it settles some each year and cracks open. i caulk the front of the crack with flexible caulk, but behind that caulk are gaps which ants/bugs will crawl through and then they can get into the house through various cracks in the walls.

    poor design for sure. i would have just put strips of wood along the bottom to seal the end up. much easier for sure...

    this past summer i had black ants (large ants which nest in wood) crawling over me here in my perch, and so i had to track down where they were getting in and seal that up. but in that search it was soon clear that the entire perimeter of the house needed a bit of work to seal it up. i wasn't about to cut out and remove the caulk already there. i just needed something i could inject behind that caulk that would seal and perhaps even bond with the cement and split stone, that it expands into spaces and seals the smallest cracks that i could not get to otherwise is definitely a great use and that it bonds with pretty much everything and holds it together is good too.

    having a long nozzle i could poke through the holes in the caulk meant i could go along and seal the entire perimeter without having to remove any of the existing caulk. well, at least i got about half the house done, the rest of it isn't settling as much so doesn't need to be done right away. perhaps in a few years i will have to do it again in places, but it doesn't take that much to do compared to the alternatives.

    when the foam finishes drying i cut away the extra that pokes back out and put a thin layer of caulk over it to protect it from the weathering/sun so that it matches the rest of the house. the front of the house that has a stone wall with a window in it was never sealed well around that window and a lot of cold air came through there with it facing the prevailing winds. i used a can of foam sealer to fill that in and then put the caulk on top of that filler to protect the foam. already i notice the difference. that one patch has probably already paid for itself. but it would have been nicer to use a material other than a foam which is based upon petrochemicals. the foam for this pad i use to perch on is made of soybean oil, but i'm not sure they could do the same thing for the cans of spray foam, probably, i don't know why not, but ...
     
  6. 9anda1f

    9anda1f Administrator Staff Member

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  7. songbird

    songbird Senior Member

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    still polyurethane, not what i'm looking for Bill. since it requires cleaning solvent to clean out that applicator gun which would make it much worse IMO than what the current stuff does (throw away one use steel can than can be recycled).
     
  8. 9anda1f

    9anda1f Administrator Staff Member

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    Ok, got you.

    The only other thing I can think of is to use oakum similar to how it's applied to old wooden ships.
    https://www.homedepot.com/p/1-lb-Brown-Oakum-963-15PK2/202274121

    From wikipedia:
     
  9. eco4560

    eco4560 New Member

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  10. TLP

    TLP Junior Member

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    The best bet is what I showed, trowel or use a mortar applicator you get at home depot to apply a mix of lime and/or fly ash binder with a rock or cellulose porous aerator to the mix. I used straw, lime, fly ash. Get a pump garden sprayer less than $10 for those tough to reach areas, take the end off to open up the nozzle and spray several coats of a lime mix that won't clog the nozzle...Shake it periodically to prevent settling. Cut the end of the mortar applicator as req'd, or use a compressor to blow it into tight areas.

    Spray can foams don't provided much r-value, they are mainly for air sealing but very toxic especially against OSB or materials that they react to causing fungi and rot. Many reports of outgasing toxic fumes the MSDS does not warn since it happens over time, after installation. When it gets wet it recures, can even explode, outgas, leach, etc....

    I recommended perlite in the other thread for under geopolymer cement slaps and footing since it drains well compared to vermiculite, so does pumice, scoria.
     

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