Crawl Space Insulation

crawl space insulation Prodex

Crawl Space Insulation - Moisture and Cold Are Primary Considerations



  • Problems Caused by Moisture
  • Challenges To Insulating a Crawl Space
  • Components of the Best Crawl space Insulation
  • Crawl space Insulation Options
  • Installing Crawl space Insulation
  • Why Buy Here
  • Crawl space Insulation For Sale
  • Pricing and Buying Crawl space Insulation 

Due to the underground environment, moisture and cold are the primary considerations in developing a crawl space insulation strategy. Excess moisture can cause mold, mildew, odors, decay, fungus growth and wood rot. Cold temperatures below will increase your energy costs and make it less comfortable to walk on your floor.

The underground environment of a crawl space presents unique challenges. The moisture content in soil below three feet deep is almost always higher than the moisture content of the air inside. This difference in vapor pressure causes moisture to be driven from the soil into the crawl space interior by diffusion through the wall. A significant amount of moisture from the soil below the slab will wick upward into the crawl space. Prodex Total, vapor barrier crawl space insulation, solves your moisture and thermal protection needs.

04c08w53: Saturday, February 06, 2010

My husband and I wanted something to replace the rodent infested fiberglass insulation in our crawl space. We also wanted something that we could install ourselves and would not attract critters or mold or put fibers into the air. I did some research and settled on prodex. We finally finished the crawl space. It took longer than I thought and was more work than I expected. We are not as young as we used to be and the crawl space was really uncomfortable. Hard on backs, knees and elbows. But it is finished and seems to do the job. We also used it to insulate our well house. Works great and we can keep it from freezing with a candle if we need to. We use it in icechests to keep things cold longer, even in the back of a pickup in the sun. My husband lined a box for our outdoor cat. We also cut pieces for our picture windows. We pop them over the windows when our power goes out in the winter. Helps keep the firreplace heat in the house. We rave about it to everyone we know. Our next project is the shop. Of course it is not the only thing on our list.

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Challenges To Insulating A Crawl Space:

  • The Soil below your home
  • Hydrostatic pressure against the foundation wall from rainfall, snow melt or irrigation creates exterior diffusion
  • Air infiltration bringing moisture in.
  • Groundwater leakage through the foundation
  • Interior diffusion from humidity in warm indoor air
  • Condensation formed due to temperature differences between ground and wall

Underground soil temperatures can be much colder than either the outside air or the indoor air. The warmer the air of the basement constantly expands. When this warm air reaches the cooler surface of a wall next to the ground, condensation will occur on the interior of the wall. Any insulation in your crawl space will be subject to potentially large amounts of moisture driven from both the exterior and the interior depending on the season.

Air infiltration can be a major source of moisture entering your crawl space. A lot more water vapor can move through a very small opening where the vapor pressure is greater on the exterior than can move through the wall surface by diffusion. Air-transported moisture can quickly lead to mold, mildew and decay in interior wall assemblies. Properly insulating a crawl space requires addressing all these challenges.

fiberglass insulation in crawl space  

Fiberglass insulation should not be used in a crawl space! To maintain its thermal effectiveness, fiberglass insulation cannot be exposed to moisture. Moisture will degrade the insulation R-value of fiberglass batts and promote mold and mildew. Installing a vapor barrier over the interior of fiberglass insulation will not prevent the foundation walls from drying to the interior, migrating capillary rise and ground water leakage. Batts with no vapor barrier will not be effective either as interior humidity will still cause loss of insulation R-value. U. S. Department of Energy: The R-value of some insulations also depends on...moisture accumulation.

R-value test parameters


crawlspace prodex total insulationProdex Total crawlspace insulation does not support mold, mild or fungus growth. It does not lose thermal effectiveness when wet. 

Your home can act like a vacuum drawing radon up through the crawlspace in two ways. First, the air pressure inside is usually lower than pressure in the soil around the foundation. Second, warm air will rise to leak out through attic vents creating a small amount of suction that can pull radon gas up through the crawlspace. A poorly insulated crawlspace can account for 15 percent or more of a building's total heat loss. Prodex is most effective against downward radiant heat transfer making it a builder's choice for crawlspaces as a radiant barrier. Heat radiating downward from your floor into the crawlspace will be reflected back inside, saving energy and maintaining constant room temperatures. The most recent advance in crawlspace insulation is Prodex Total as a vapor barrier, radon barrier and insulation combined in one product.

Components Of The Best Crawl Space Insulation

  • Keep your floors noticeably warmer
  • Reduce air infiltration and drafts
  • Save energy and money by keeping heat and air conditioning inside
  • Minimize problems with condensation, wood rot, mold and mildew
  • Provide waterproofing
  • Seal entry paths against termites
  • Control radon infiltration

How To Insulate a Crawl Space

Today's building codes call for un-vented crawlspaces. Crawl space walls are typically only insulated if the crawl space is un-vented and the floor above the crawl space is un-insulated. While walls can be insulated on either the interior or the exterior, interior insulation is the preferred approach if you want the insulation to double as a vapor and radon barrier. Crawl spaces are most commonly insulated on the ceilings and the floor and less frequently on the walls.

Crawl Space Insulation Options 

As stated previously, fiberglass insulation loses R-value when wet, and it will get wet in a crawlspace.

Rigid board is problematic because it's rigid. It's rigidity doesn't allow it to conform to an uneven wall (most basement and crawlspace walls); consequently you'll have air infiltration and moisture problems.

To solve the heat-loss, moisture, and air infiltration issues use: 

Prodex Total 10M72 Inch, 48 Inch, 24 Inch, 16 Inch or Fast Action on the crawl space ceiling or walls. Use Prodex Total Under Concrete Insulation on floor (white side facing down toward the dirt). 

crawl space insulation prodex large

Installing Crawlspace Insulation


A. Staple Prodex 48 Inch or Fast Action under floor joist. Tape seams with reflective tape or use Prodex Fast Action or 10M to avoid seam tape.

B. Depending on joist spacing, using 1/2" staples, staple  Prodex 16 Inch or 24 Inch between joists at staple tab 2" to 4" below floor board. Tape seams with reflective tape. 

C. Combine method A and B to maximize performance. 

Wall: Use glue (super metal sealant) and double sided tape to attach Prodex to concrete wall.

Floor: Roll out Prodex Total Under Concrete on crawlspace floor - White side down facing dirt. Overlap insulation by 3 inches and tape seams with reflective tape.

Confidence - Buy Crawl Space Insulation Here

  1. Independent Prodex Insulation Reviews at Site Jabber. Site Jabber is the leading community of online business reviewers. The community helps consumers find great online business and avoid scams. The community has grown to over 850,000 members and has reviewed over 58,000 online businesses. Site Jabber was developed in part with a grant from the National Science Foundation.
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  3. Prodex Insulation Reviews on every product page
  4. ICC-ES Recognized - ICC-ES is an evaluation service that takes independent test data for a variety of products and analyses it against a uniform Acceptance Criteria that is recognized internationally.
  5. Over 4 billion square feet sold worldwide.

Insulation4Less Reviews: Some review sites are pay to play :(

Crawl Space Insulation for Sale 

prodex insulation cross sectionProdex Total 5M Plus . 5mm (0.2") closed cell polyethylene foam covered on both sides with reflective reinforced foil facing. 

prodex insulation cross section

Prodex Total Under Concrete: 5mm (0.2") closed cell polyethylene foam with reflective reinforced foil facing on one side and polyethylene white backing  on the other side.                               

 Prodex Total 10M New TagProdex Total 10M Plus. Twice as thick as regular Prodex Total.  10mm (0.4") closed cell polyethylene foam covered on both sides with reflective reinforced foil facing.



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Crawl Space Insulation Prices | Buy Crawl Space Insulation

  • Roll Pricing on every product page
  • Shipping calculator on every page in blue bar
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metal building insulation prices 

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Prodex Insulation Reviews
Handyman78: Thursday, March 24, 2016
Hello. Thank you for your wonderful insulation. We ordered some early last spring to insulate our crawl space that had never been insulated for 33 years. It works great! We love the additional illumination with the space lighting making the space a warm comfortable area to work in when we need to go down under. Thanks again Kristie
Prodex Insulation Reviews
dejones420: Monday, February 16, 2015
your product is awesome in every aspect , from it's R value , performance , and ease of installation . not to mention the price !!!! Prodex saved me hundreds of dollars in material cost and hours of time due to it's easy installation ...My building inspector had never seen it and was impressed with it's specs. and the look of the finished job !!!I have attached a photo of the job ..... and have recommended your product to two different companies that due sealed crawls in the Charlotte NC area , Climatec heating and air , and Austin Insulating . Thank You ; Douglas J. / United Structural Maintenance Co.

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