Blown in

Larry Weingarten

...Dave's statement about there being no way wo make a house air tight. Field practice has shown that even with a blower door to find the leaks, it is very unlikely one can make a house too tight (less than ~.35 ACH). That does not hold for new construction, particularly with SIPS or any other monolithic construction. So, seal to your heart's content and separate combustion appliance air from indoor air.

Yours, Larry

Mark_46

Tips for cellulose

Any suggestions on what to look for regarding cellulose blown in insulation? I will have a few walls and my attic floor done. Know of a good installer? I am in north eastern New Jersey.

Brad White_9

Dense-Pack

There is a product/system called Nu-Wool which uses a method (may be generic) called "Dense Pack" (Dens-Pak, whatever! You know how those tradenames work).

The key is to have it blown under pressure such that through-wall infiltration is greatly reduced. They claim you do not need a vapor barrier but I would still use a vapor barrier paint regardless, at least.

The material is more uniform and granular, it seems to "pour" around wiring, piping and so-on. Packs nicely. Not sure of any vendors in your area but there is national representation. I did get Nu-Wool spelled correctly though!

Good Luck

Brad

Mark Hunt

Important to keep in mind

> There is a product/system called Nu-Wool which

> uses a method (may be generic) called "Dense

> Pack" (Dens-Pak, whatever! You know how those

> tradenames work).

>

> The key is to have it blown

> under pressure such that through-wall

> infiltration is greatly reduced. They claim you

> do not need a vapor barrier but I would still use

> a vapor barrier paint regardless, at least.

> The material is more uniform and granular, it

> seems to "pour" around wiring, piping and so-on.

> Packs nicely. Not sure of any vendors in your

> area but there is national representation. I did

> get Nu-Wool spelled correctly though!

>

> Good

> Luck

>

> Brad





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Mark Hunt

Important to keep in mind


We are seeing quite a few posts here on The Wall lately regarding insulation upgrades.

I agree 100% that lowering the BTU loss/gain in a home is the best way to lower energy consumption. No brainer there!

I must stress that when we change the dynamics of the building, i.e. less infiltration, there is the possibiltiy of causing atmospheric vented appliances to back-draft. I have seen this happen. House gets "sealed" and the furnace and water heater spill flue gas whne the clothes dryer runs or the exhaust over the stove is turned on.

It is EXTREMELY important to test the CAZ(Combustion Appliance Zone) once the building is made "tighter". An atmospheric appliace may draft just fine before the modifications to the house are made, but once the shell is tightened up they may not.

These changes can effect the combustion process as well.


Unless someone is testing, you will not know.

Mark H

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Brad White_9

Excellent point to bring up, Mark

In our enthusiasm to conserve BTU's and given that older houses seemed to get their combustion air "naturally", we might defeat that. Few things in life so inoccuous as that cause death.

You have changed my thinking with your talk in June with Mr. Milne and friends.

Insulate, but ventilate. By design, not by chance.

Thanks, my friend.

Brad

Dan_15

There are myriad opinions on this subject. Im a H.O., too, who can't settle on the right answer. I want to insulate, but I know MH is right that blown in insulation changes the dynamics of a house, particularly an old house. Old houses do not have the benefit of moisture barriers and modern vapor control. They are built to "breathe". Start plugging up the stud bays without addressing moisture infiltration through the sheathing and I am afraid of ending up with a mold problem. I think sprayed foam and icynene is great if you have the luxury of re-siding your house with proper moisture control, but I am wary that blown-in cellulose only addresses half the problem and worsens the other half.

Mike C.

Good Resource

I would highly recommend reading the book "Build Like a Pro: Insulate and Weatherize" by Bruce Harley. It's a great resource for weatherization (insulating, air sealing) and also heating/cooling appliance upgrades.

It's broken down in a way that's easy to understand. They look at the house (building) as a total system.

Something else worth looking into is an energy audit. Many times there are utility incentives for increasing insulation levels, appliance upgrades, etc...

Rob_32

tax credits for envelope improvements

http://www.energystar.gov/index.cfm?c=products.pr_tax_credits

Other stuff, too. See the link to the chart.

D107

i assume you're in the NE?

HO here. check out building science's book 'cold climates'--or their publication that fits your zone-- which goes into detail on these issues. In the northeast moisture infiltration happens in the summer. Moisture moves outward in winter. There are various things you can do on the inside of the house to keep moisture from moving outward where it could condense and cause problems. I had cellulose blown in and from an infra-red test I had done I could see that it in no way makes a house airtight. So I feel pretty safe there.

If I create a conditioned space in the attic via polyicinine foam under the eaves and on the gable walls I would putin a simple HRV ventilation system attached to my existing central air conditioning to periodically change the air and maybe add some dehumidification or create slight seasonal negative or positive air pressure to keep humidity in or out. And there's the vapor barrier paint Brad suggested. Vinyl wallpaper is considered too much of a barrier that prevents summer humidity from drying to the walls cooled and dried by air conditioning. That can keep moisture trapped between wallpaper and wall--which happened in our house.

Since I haven't sealed the open boiler room band joists I still don't need a fresh air intake. (had combustion test)But once I seal the band joists I will get an FAI not only for safety re: CO but also to stop pulling in cold air into the house.

good luck,

David

Mark_46

Brad

Thanks for the Nu-wool lead. I looked at their website and have already been in touch with the dealer for my area.

Harold

If you use a closed cell spray foam you should not need to worry about vapor if it is done correctly. Apply a thickness that keeps the worst case dew point inside the foam. Not on the inside surface of the foam; inside the body of the foam. Vapor infiltration from the inside will not condense. Nor would you, I believe, need to change the outside structure. You do have to have complete access to the spaces you need sprayed. This foam will also provide the best air seal you can get in anything other than a properly built SIP structure. It even adds to the lateral strength of the wall.

Bob Harper

dangers

Ditto Mark on the CAZ testing and I'll add:
maintain stated clearances around chimneys and gas vents with shields. Insulation piled up against hot things causes fires!

Mark_46

Brad

After meeting with the Nu-wool representative, I learned more about what you were describing. Turns out, Nu-wool also governs the equipment used by the installer, effectively controlling the quality of the install too! In order to achieve that 'dens-pak', it must be blown in under higher pressure.

Brad White_107

Exactly, Mark

It is a system. A friend made use of them year before last and it made quite a difference in the sound (much quieter; city streets) and draftiness (caulking did play a role of course). Add to that the thermal benefits. Now we just have to get her a good boiler and a lot more radiation. (Fixed income disabled). But at least the heat loss is down.