Understanding "Diffusion". 

The following information is "on average" and used to illustrate how moisture enters our buildings. Current diffusion rates due to product improvements may differ. 

In other words, CYA with the lawyers. 

Definition: diffusion refers to the movement of water vapor through materials due to differences in vapor pressure. This process occurs even in the absence of air leaks and is driven by the tendency of water vapor to move from areas of high vapor pressure to areas of low vapor pressure. Understanding vapor diffusion is crucial for managing moisture in buildings and preventing issues like condensation and material damage.

We all know the effect of moisture on our flooring products. I once heard 

Mark Cordle, national building and code compliance inspector, explain to a tech at Southface Institute in Atlanta that flooring is like the canary in a birdcage in mines. 

Before our sensing equipment we have today the canary would die, stop singing, when the miners hit a pocket of poison gas. They knew to move fast to live. 

Warped flooring, mold, discolored flooring and subfloors, so many indicators you can confirm with moisture meters used correctly. Unfortunately, many flooring contractors fail to use moisture meters and hygrometers that are available to them to avoid costly replacements of flooring, that steal their profits. 

In the photograph above, that is just one 4' X 8' gypsum panel or board. How many are in a construction site? 

There are building wraps and you say, OSB o r plywood? 

Here you go: (osb and plywood) Class II or Class III vapor retarder category, with perm ratings typically ranging from 1 to 5 perms. 

House wraps: acts as a weather-resistive barrier installed under siding. It's designed to be water-resistant to prevent bulk water intrusion into the wall assembly, while also allowing water vapor to escape from the inside, preventing moisture buildup and potential rot or mold. 

General Perm ratings suggest by some building experts suggest that a perm rating between 10 and 20 is ideal for balancing moisture management in a wall system. Some popular brands can have as much as a 56 perm rating. The goal is moisture control in the walls. 

Now, back to what can happen to our floors, not walls. 

One air leak, such a hole cut for a pipe or electrical wires? 

Look at how much can happen with just the one hole, whatever type of wall panel. What is there are gaps in the wall wraps? holes punched in the wraps? Possibly, hundreds of small holes! 

This is important information you should know to understand problems you encounter but more important, prevent. Using the right tools and meters, and how to use them, can save you money and prevent costly callbacks. 

We recommend two meter companies, Tramex and Delmhorst, and each has wall probes (that can be used for many purposes) and attachments that can be slid under quarter rounds and wall bases to help measure moisture diffusion. Guild students receive a direct discount from the companies

Below are examples of water leaks damages and moisture diffusion. 

Knowledge is power to prevent loss of reputation and profits.