Your opinion--Best insulation

"basically eliminates air infiltration" ???

I have erected a steel building. we are spraying-in-place a layer of Fomofoam. that gives a TOTAL seal against air infiltration. Not just a basic seal.

Also there is no bridging from studs. No studs! the structural columns are 18 inches from the walls. the interior walls can be placed 4 inches in from the outer walls, or 6 inches, or 8 inches, or 18 inches. That entire void can be filled with any insulaiton you wish to use, and no thermal bridging (except for the window frames and door frames).

I have used Spray-in-foam before, and I love it. Your walls will be 6 inches thick? cool. Fomofoam can be bought in those little bottles, or in other sizes all the way up to 600 pound tanks. Two canisters either way, it is an epoxy and sticks to ANYTHING. One tank is 'A' the other is 'B'. both components are okay to work with, but once they are mixed they will be stickly, it will rise and will quickly cure. It is not UV safe, if left un-protected to the sunlight it will crumble over the course of a few years. but you could easily make your house like a styro-foam ice chest with walls 6 inches thick.

If you go to the DOE [not a insulation manufacturer], they say that the *best* insulation is perlite. Perlite is a volcanic glass heated and air-popped like popcorn. It is fire-proof and it is supposed to be the absolute *best*. We are planning on spraying in aobut 2 inches of foam, then filled the rest of our void spaces with perlite. It is used in the Cryo-genic industry for building rooms using liquid nitrogen systems.

I bet that for your home, 2 inches of foam and 4 inches of perlite inside of that, you might be able to heat the home with a candle.

www.fomofoam.com

I really truly am NOT a salesman. I have used this stuff though, and I really like it.

I looked into insulating our house myself using Fomofoam, but it actually ended up being cheaper to have an insulation contractor come and spray foam in. I guess it just depends on the area where you live, so just check the prices.

I didn't know about perlite when we built the house, though. I'll have to look into that and maybe figure out a way to add some, or use it if we ever add on...the house is already incredibly energy-efficient, but you can never be TOO efficient.

You can get sheep wool insulation now, very green, very healthy.
Probably not as convenient as the local home center but you're stuck with your choice for long long time...
this picture is worth a thousand words:
http://www.sheepwoolinsulation.ie/

Cellulose would be my second choice.

__________________
Hut on the Hill Farm
http://www.hutonthehill.org

I did the great room of my house, walls and attic with blown in cellulose.
It's treated with boric acid as a fire retardant, but, it also seems to keep bugs and mice away.

__________________
To announce that there must be no criticism of the President, is not only unpatriotic and servile, but is morally treasonable to the American public.
-Theodore Roosevelt

Hi,
Not to beat this to death, but one thing to bear in mind is that even though the foam in place stops air infiltration through the wall cavity you still need to do a careful job of sealing below the bottom plate and above the top plate. The Southface.org study on infiltration sources lists these a major sources of air infiltration.

Southface.org Air Sealing Guide:
http://southface.org/web/resources&s...g%2000-767.pdf


I think that if I were building new, I would take a good look at the comparison between SIP construction vs sticks with foam in place.

Gary
www.BuildItSolar.com

I do worry about being too effecient.

I'm going to super-insulate because is cheap and easy for me. I've stick-framed two stories inside of a metal building. R-10 was installed with erection of the bldg. I still have about a 6" gap between the R-10 and and the stud framing plus the 4" and 6" wall space between the studs. I'm also spraying 1" offoam over all metal purlings and beams, around windows and over the existing insulation.

Worries:

1. No one can figure what BTU's I should get on a heat pump - there are no tables except for with DOE recommended insulation

2. How to get rid of water? Baths will be vented. But then there's breathing, dishwasher, spills, and cooking. If I oversize the heat pump it will have short run times and not remove enough water.

3.Stale air is is more easily figured. So many CFM exchange per volume of air in the rooms. But makes you wonder at what point it would be best to leave enough infiltration.

Something I have started seeing builders do is when building with 2x6 walls they spray in 2" of foam before the electrical roughin. Then add fiberglass batts after the electrical roughin. They say it gives them the best of both.

Very good site, thank you!

To compare wood stick with Spray-in-place foam, with wood stick with foam in place?

I missed you there.

No but you can EASILY built a home that is far too tight, and suffer a whole range of issues from mold growth, to indoor air quality issues. An extremely energy efficient home needs to be designed and built with a lot of planning that isn't required for a typical home. Once you are approaching "air-tight" you need to be very careful with make up air for any combustion appliances and a heat exchanger ventilation system that provides controlled amounts of fresh air to the building. Nothing about this is new or controversial, information has been available for the last two decades at least. Building a tight house can be a great idea, and result in a wonderfully comfortable, and economical home. It can also be a disaster if it's not done correctly.

Any good heating and cooling professional should be able to calculate the correct size you need. Yeah, it's more complex than the standard houses built these days, but it can be done...and it's worth it. They have a formula for every little detail and put them all together to get a pretty accurate assessment of your heat loss. There's also a way to test the air-tightness of the building envelope...they put a big fan in the front door and measure pressure differences and resistance or something. I don't really know how that works because it's mostly for existing houses. There's no way to just guess/oversize and be "close enough" like they used to do in most houses, but the heating and cooling people know how to figure out what you need.

If you have no means of air exchange, then of course you can build a house too tight, but if you have proper ventilation you can live in a bubble completely sealed off. The way I see it, it's best to seal up the house as much as possible and then add ventilation equipment so you can control EXACTLY how much air exchange takes place. That sure beats hoping you have enough, or overdoing it and unnecessarily wasting energy. I have one of the most efficient heat recovery ventilators available...it wasn't cheap, but it's already payed for itself in the first five years. It monitors humidity, oxygen levels, etc. and reacts to keep them in the proper range. And it makes the house a lot more comfortable and healthy to live in.

In our case we have both medical as well as religious reasons for wanting to control when, where, and how much air enters our new home.

So we want the house to be entirely airtight, as well as slightly pressure tight.

At scheduled times throughout the day our home needs to be ventilated to allow out-gassing.

All make-up air needs to be filtered, de-humidified and the oxygen content needs to be 'adjusted'.

This can all be done using: a wet filter [like a swamp-cooler], a heat-pump high-efficiency dehumidifier, and an O2 concentrator.

Consider what a home would be like if it were a hyperbaric chamber.

Kuriakoa, You and I are making the same point here. I have built several homes that were tight enough to require blower door testing for final tuning and certification, and obviously they required air to air heat recovery ventilators. It's important to remind folks that this isn't new technology, it just has been largely ignored here in the USA. It is quite possible to built a cost effective, very energy efficient home with great indoor air quality. Taking a typical stick home and just spray foaming the stud bays isn't enough. This can result in problems like mold growth on corners and closet interiors, occupant health issues due to indoor air quality a lack of combustion air volume for heating units, water heaters and dryers, and backdrafting of furnaces and woodstoves. An airtight house is a whole package of air sealing, insulation, heating and cooling requirements, and ventilation issues. It's worth the extra time and money, but it requires thinking about the whole package, not just insulation.

Hi,
I meant to say I'd compare construction with SIPs to construction that uses conventional stud walls with the Polyurethane foam sprayed in place.

The SIPS are the panels that have a rigid foam board core with sheets of OSB for the inner and outer skins. They don't have any studs, so there is no thermal bridging through the studs, and they come in big panels, so there are fewer seams to leak air. The materials for SIP homes cost more, but the labor is supposed to be less -- so maybe the cost comes out about the same?

If anyone has pictures of a SIP house in progress, I'd love to get them for the Solar Homes part of my website.

Gary
www.BuildItSolar.com

I understand now. Yes I have seen those advertised.

I think that if you can spray Polyurethane foam in place onto the outer skin of a building, with no studs just a number of inches thickness of hard foam, it would take care of any posible bridging and it seals against any possibility of air leaks too.

I've thought about the hyperbaric house idea...basically just increasing the pressure and oxygen levels, but I haven't done much research as to how practical it would be. It's interesting that someone else is thinking along the same lines, though. And just out of curiousity, do you mind if I ask what are the religious reasons for controlling the air in your home? Just going along with living healthy, or is there something else to that?

You must mean increasing oxygen just a moderate amount, like with plants and stuff. If you go too high you create serious fire hazards. Also, your lungs and body can get used to oxygen levels being elevated and become dependant on them. Of course if you are on oxygen I can see how it would be tempting to avoid haveing to carry the tank around, but the fire risk would be too great, and you would spend a fortune on oxygen as it would leak and even oxidize stuff within the house maybe.

It did not seem to do howard hughes a whole lot of good. And he had enough cash to use the finest of equipment.

There is much research, there are disucssion groups of folks who deal with chambers as well.



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