Ask an Inspector: Poly Urea Spray for Crawl Space liner
Michael Rettie <> (Add as Preferred Sender)
Date: Thu, Jul 09, 2015 7:43 am
To: “” <>
Cc: Dan Bruce <>

Matt Garrett,

Thank you for your question. Orange County Inspections would need the product documentation to include an approved evaluation report (such as an ICC-ES report) to approve this request as alternative materials and methods. The link provided in not found and no information is provided. Based upon the general nature of your question it appears you are seeking an alternative to the prescriptive 6 mil Poly used to encapsulate the crawl space. I can say that the “termite inspection gap” is for the thermal insulation not the liner. Even with a spray on coating the thermal insulation would need to provide for this gap. I am not sure how this product works to be applied to the soil of the crawl space or how the required vapor barrier would secure to this product, I can only assume this would be covered by the product documentation. The treatment for protection against termites require the soil to be treated in the crawl space, not sure where the “need for termite spray on the inside walls…” is documented. Spraying “over the top of the foundation” would not eliminate the requirement for a sill seal gasket (or caulk), this practice does not have any Code influence. If you choose to install the thermal insulation in the floor system I would guess that this product would be acceptable as described, with clarification for the interconnection with the vapor barrier on the ground. IF you are seeking to use this product in combination with spray foam insulation the limitation and criteria for providing the spray foam would also be required.


I wanted to try a 40 mil white poly urea spray as the crawl space line in new home construction. And spray it on when foundation and block wall are cured and there is no floor on… this would make for easier spraying. I would like to spray the monolithic 40+mil white liner over the top of the foundation walls so the sill plates would sit on top of it. This would be sprayed 12 inches + up all columns cover all walls and go over the top of foundation block on top. No Termite 3 inch gap because there are no penetrations in the monolithic sprayed polyurea. If I can … would this illiminate the need for termite spray on inside walls of foundation? Plumbing and electrical holes would be punched through it later in the building process and we would go back after all penetrations made and poly urea spray seal back over to ensure perfect seal. Q1: Can I use this 40+ mil white polyurea spray as a monolithic covering. It would be a perfect radon vapor barrier since no seams or tape are involved. It would also SIGNIFICANTLY strengthen the block walls. I appreciate your time!

I hope this answers your question.

Michael Rettie

Chief Residential Inspector CEO III

Residential Plans Reviewer

Orange County Inspections Department

(919) 245-2616

All e-mails including attachments sent to and from this address are subject to being released to the media and the public in accordance with the North Carolina Public Records Law.

Posted code interpretations:

View the 2012 NC State Building Code free on line:

Leave a Reply

Your email address will not be published. Required fields are marked *