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Expanding Spray Foam Insulation and Indoor Air Quality


faskippy's Avatar
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Join Date: Dec 2009
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12-05-09, 03:39 PM   #1  
Expanding Spray Foam Insulation and Indoor Air Quality

Hello! We are planning our new home for Spring kickoff. I've talked to a few old friends who stick build, and told them we want the Exp. spray foam insulation. I gave my reasons as efficiency, noise, comfort, etc. though efficiency would be enough, one would think. I've had a couple try to discourage me from this option, saying that indoor air quality with it's use is not good. One told me that with a home sealed this well, it couldn't "breathe", and that it would require a costly system in addition to the regular HVAC system to bring in fresh air, thereby negating the efficiency. The other reason was moisture buildup. ??? I can understand not wanting stagnant air inside your home, but, there has to be a solution to this that is tried and true. This form of insulation is not rare anymore. Can someone please elaborate on the pros and cons of this form of insulation, and tell me if these guys are behind the times on their info, please?

 
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Bud9051's Avatar
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12-05-09, 04:15 PM   #2  
Hi Skippy and welcome to the forum.
IAQ (Indoor Air Quality) is indeed a hot topic and one of the primary reasons is exactly what you were told, tight homes. But a tight home is a good thing, not a bad one. The principle is controlled air exchange rather than random. Plus in a controlled manner, much of the energy that might be lost by "changing the air" can be saved. And the cost of running the required equipment is reasonable. Check out ERV's, energy recovery ventilators. The exhaust air passes through a heat and moisture recovery unit that conditions the replacement air and then delivers it to where it is needed. In an uncontrolled leaky home, air is entering and exiting through walls and ceilings where it can deposit it's moisture and create problems.

By learning now before you start construction, you will be able to create an extremely energy efficient home that will be comfortable all year long. Spray foams are good, expensive, and not the only solution. Green products have entered the field and new products and new techniques abound.

Enjoy your planning,
Bud

 
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12-05-09, 04:25 PM   #3  
Bud is right. A House doesn't need to "breathe". Those guys are behind the times.

In a house that "breathes", the air the comes in and out of it is uncontrolled. The rate at which it comes in and out varies depending on the weather. The last thing you want to do is drag moisture and dirt through your batt insulation.

You should have adequate venting in your kitchen and bathroom to deal with moisture. Make sure those fans are not undersized.

Pick up this book: Amazon.com: Insulate & Weatherize (Taunton's Build Like a Pro) (0094115585545): Bruce Harley: Books

It will help you a lot in understanding what's right when it comes to insulating.

 
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12-05-09, 05:21 PM   #4  
Posted By: Bud9051 Hi Skippy and welcome to the forum.
IAQ (Indoor Air Quality) is indeed a hot topic and one of the primary reasons is exactly what you were told, tight homes. But a tight home is a good thing, not a bad one. The principle is controlled air exchange rather than random. Plus in a controlled manner, much of the energy that might be lost by "changing the air" can be saved. And the cost of running the required equipment is reasonable. Check out ERV's, energy recovery ventilators. The exhaust air passes through a heat and moisture recovery unit that conditions the replacement air and then delivers it to where it is needed. In an uncontrolled leaky home, air is entering and exiting through walls and ceilings where it can deposit it's moisture and create problems.

By learning now before you start construction, you will be able to create an extremely energy efficient home that will be comfortable all year long. Spray foams are good, expensive, and not the only solution. Green products have entered the field and new products and new techniques abound.

Enjoy your planning,
Bud
Dead on! Again a ERV or HRV must be used in a tight home. Cost for one installed is less than 2 grand and should last a long time.

 
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12-06-09, 06:59 AM   #5  
Essentially they are arguing against insulating it properly so that gaps in the house can assist with airflow. I can't imagine that that approach is more cost effective than sealing the house up and having an active air system, which you can fully control. Probably the worst situation, which is what most of us with newer homes have, is a fairly tight home but no active air movement. Certainly none of the homes in my neighborhood, all a few years old, have any active air movement at all other than that pushed out of the roof by the furnace (when it's on).

 
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12-06-09, 07:14 AM   #6  
There was a time when a house could be 'too-tight' but that was when we first started trying to make them tight and didn't know all of the spin-offs of doing so. We've caught up now and the ventilation needed is available. Your friends have not kept up with the times.

 
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