RE: Re: [VAC] Expanding foam sealant

[Gene Williams <realty@aristotle.net>]

Notes of interest concerning foam:

Expanded polystyrene

The unique closed-cell structure of EPS permits water vapor in wall cavities to escape without significantly affecting insulation properties. Of foam plastics, it's one of the most resistant to the effects of moisture absorption. Although molded EPS has a low water vapor transmission rate, it is not a vapor barrier. Its unique properties have proven acceptability in cold storage applications



For those thinking of foam applications:

http://www.rhhfoamsystems.com/literature/mfb-1/index.html

http://www.exelfoam.com/faq.htm 

How long has Polyurethane Foam (PUF) been around?  
It was developed during World War II for flotation.
 
Is it expensive?  
The price of a PUF system may be higher, but the cost of owning it is less. Heating and Cooling costs drop an average of 30%.  

Does it have formaldehyde in it?  
PUF contains no formaldehyde.  

Does PUF absorb water like a sponge?  
Properly applied PUF is a completely closed cell material and will not absorb water.  

Can you walk on it?  
Yes. PUF used for roofing has a compressions strength of approximately 45 pounds per square inch.  

Is PUF a good insulator?  
One of the best! It has an R factor of approximately R-6.5 per inch.  

Will it stick to my roof or walls? 
PUF will adhere to almost all clean, dry surfaces.  

How long will it last?  
PUF has been shown to last 20 years with no internal degradation. No one knows how long it will last if well maintained. 

Will the Foam crack on my roof or wall?  
Foam has excellent elongation and will "move" with the surface it is applied to  

Can Foam withstand hurricanes?  
Building with PUF coated roofs or walls have survived storms better than those built with conventional building materials because the Foam is a "structural" material giving strength and flexibility to the surfaces it is applied on.  

What is the service temperature range?  
From very cold (-100 F) to very hot (+225 F)  

Does Foam burn?  
It will burn and has flame spread and burn characteristics similar to white pine.  

Can I buy the material and do it myself? 
No. Correctly spraying PUF requires special equipment and properly trained technicians. 

 
Gene