# Perlite in sleeper floor



## Keystone (Dec 29, 2017)

Existing SFD enclosing garage for habitable space, sleeper floor joists added over concrete floor. Contractor used Perlite for floor insulation. Thoughts on using perlite in floor application?


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## Francis Vineyard (Dec 29, 2017)

To my knowledge perlite has been used and is currently acceptable but under-performs other insulators.

Not to be confuse with vermiculite that may contain asbestos is prohibited.

Suggest for additional information search keywords "insulation contractors perlite"


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## Keystone (Dec 29, 2017)

Francis Vineyard said:


> To my knowledge perlite has been used and is currently acceptable but under-performs other insulators.
> 
> Not to be confuse with vermiculite that may contain asbestos is prohibited.
> 
> Suggest for additional information search keywords "insulation contractors perlite"



Its definitely not vermiculite.


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## Robert (Dec 29, 2017)

Keystone said:


> Its definitely not vermiculite.


As an aside, how are you handling a vapor barrier? Since probably not one under the garage slab. Is there a paint on product that has the qualities of a below slab poly or membrane sheet?


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## Keystone (Dec 29, 2017)

Robert said:


> As an aside, how are you handling a vapor barrier? Since probably not one under the garage slab. Is there a paint on product that has the qualities of a below slab poly or membrane sheet?



Valid point and that is another issue that the contractor has to answer. No vapor barrier placed. We would require a vapor barrier, what we see is poly.


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## mark handler (Dec 30, 2017)

http://www.schundler.com/underfloor.htm
Why Perlite Insulation?
Perlite underfloor insulation is an inorganic product that does not rot, support combustion nor provide a habitat for rodents. Because of its neutral pH, the product does not foster corrosion in piping and electrical wiring that may be in the underfloor area.
When used for underfloor insulation, a water repellent, dust suppressed perlite specially produced for this application is used.


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## tmurray (Jan 2, 2018)

Keystone said:


> Valid point and that is another issue that the contractor has to answer. No vapor barrier placed. We would require a vapor barrier, what we see is poly.


Would the thickness of the floor sheathing meet the permeability limits for a vapour barrier? Anything meeting code for thickness does here...


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## Msradell (Jan 2, 2018)

tmurray said:


> Would the thickness of the floor sheathing meet the permeability limits for a vapour barrier? Anything meeting code for thickness does here...


I've never been any place where floor sheathing was used to meet the permeability requirements vs. a vapor barrier. There may be someplace where it is but...


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## tmurray (Jan 3, 2018)

Vapour permeance for common sheathing materials: https://photos.app.goo.gl/iafYfJFTExir5dRN2


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## Keystone (Jan 3, 2018)

mark handler said:


> http://www.schundler.com/underfloor.htm
> Why Perlite Insulation?
> Perlite underfloor insulation is an inorganic product that does not rot, support combustion nor provide a habitat for rodents. Because of its neutral pH, the product does not foster corrosion in piping and electrical wiring that may be in the underfloor area.
> When used for underfloor insulation, a water repellent, dust suppressed perlite specially produced for this application is used.



I wish I knew why the contractor used Perlite. Odd choice to say the least.


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