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You need to know about water perm vapor transmission!

20 Sep 2016 | Under Energy Efficiency | Posted by | 0 Comments
R&A Contracting - Water perm vapor transmission

Let’s talk about perms. No, not the hairstyle perms – we’re talking about water perms!

What’s a water perm? A water perm is a measurement of water as it passes through a material over a period of time. The key part is that there needs to be a static vapor pressure difference between the two areas: where the water is coming from, and also, where the water is going.

Wait a minute- what’s ‘vapor pressure’? It’s a combination of relative temperature and humidity. If the vapor pressure in one area is greater than the vapor pressure in an adjoining area, the water vapor (water molecules that are air-borne) will want to move from the higher pressure area to the lower pressure area. Think about when it’s early August here in St. Louis and the temperatures are flirting with triple digits. The humidity is probably pretty high as well, maybe around 90 percent. Your A/C is running nonstop and that means cool air is keeping your comfortable… but it’s a fight.

The cool air from the A/C invades your office and it’s dry because of no humidity. Outside is hot and humid, but inside is cool and dry. The heat outside is putting pressure on your building’s energy envelope as the humidity in the suffocating air outside is pushing against your insulation barrier to come inside. The opposite is true in early January when it’s in the 20s and we’re bracing for another city-stopping ice storm. Your furnace is blasting hot air through your building and it’s causing the moisture in the air to rise in contrast with the cold outside.

What does this have to do with a perm of water? One of the ways we measure a building’s energy efficiency is by measuring how much water vapor seeps through an insulation type over a period of days, weeks, and months. This is often a minuscule amount but it lets us know where we may need to apply more insulation. You can’t always detect air in insulation applications, but you can often tell the effects that moisture is having on a building’s energy load.

Is water vapor affecting your building’s energy envelope? Our R&A Contracting team can help you find the weak spots and what solutions can help reduce energy loss and water vapor transfer. Let’s start a conversation today!

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Jim Lowry - Bissinger's Handcrafted Chocolatier

Eric and crew were really nice to have around. They were courteous, careful and caused little if any disruption. Their work looks good too! To be honest… a good experience with a product that I initially had misgivings about. I’m a convert because of Bubba, Sam and Eric. Thank you.

Jim Lowry - Bissinger's Handcrafted Chocolatier

“I want to thank the crew at R&A for a job well done on our very leaky roof at the shop. It is certainly nice to have the drips and rivers gone from the shop when it is raining. I also wanted you to know how much we appreciated that the guys were able to stay out of our way and allowed us to do business as usual without any problems or interruptions. The roof looks great and the clean-up after the job made it so we couldn’t even tell you’d been here. Thanks for doing what you do so well!”

Jay Moore, President of Safe Way Tire and Auto Center

“My wife and I were on vacation when water pipes burst in our house. We got a hold of Craig and the R&A crew was able to start evacuating the water immediately. The best part was that they were able to start work before we even returned home. It was a very fast turnaround considering the extensive amount of water damage.”

Will from Dardenne Prairie, MO

“Craig and Mike came out in a timely fashion when we needed the work done. They did a reliable and quality job.”

Jerry from SLR Properties

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Lindell from Greater Missouri Builders (GMB)

“We purchased a house and there was some damage to the roof. Very impressed with the thoroughness of Mike’s inspection. Very comfortable with their explanation of what needed to be fixed. Most impressive was the way they protected our landscaping. Really liked the way they treated me as a valued customer, even though it was only a small project.”

Ross from Troy, MO

“I use R&A Contracting when my commercial roofs receive storm damage. They work on our behalf through every step of the insurance claim process. They perform all of the work and complete the insurance process, making our roofs better than they were before the storm.”

Director of Facilities for a large Property Management Company

“The team at R & A Contracting responded immediately when notified of our water disaster. They removed water-damaged materials and property quickly and restored our home even before the final settlement from our insurance company. They minimized how long our family had to live in a hotel and got us back to normal as fast as possible.”

Will from O'Fallon, MO