Insulating

[hupte]

I would go with as much spray foam as you can. I put blow in insulation in my shop a few years ago and it gets more drafty every year. I'm going to pull all the cellulose out and get it sprayed. I also have a 100 year old drafty farm house with original windows. so its really drafty too. the walls of the house were blown in cellulose in the late 70s. so all that cellulose settled over the years. the spray foam will pay for itself in 6 years. if I was in your position I would pull all the siding and get the whole house sprayed. I know u just painted it but how many years do u want to live in your house? 30 years? do u want to wish everyday for the next 30 years that you would have done it the right way? do u want to wish u had a warmer house? just my .02

 

[justchecknjr]

Spray foam in a cathedral ceiling is a bad idea! Unless you put stops in to provide air flow between your roof sheathing and the spray foam. If you don't, your shingles will have a very short life due to heat buildup in summer. Dense pack cellulose is the best choice if your truss depth allows sufficient space. You'll still need insulation stops to allow air flow though.

Google hot roof system, or closed attic. the whole reason for the baffles is to move air on the surface of the sheeting to prevent moisture. if spray foam is in direct contact with the surface, in the right depth, hot cannot meet cold and there wont be a problem. It's a common practice in the southern states with a lot more intense heat and sun, and there isn't a noticeable decrease in life span.

 

[rmount]

Google hot roof system, or closed attic. the whole reason for the baffles is to move air on the surface of the sheeting to prevent moisture. if spray foam is in direct contact with the surface, in the right depth, hot cannot meet cold and there wont be a problem. It's a common practice in the southern states with a lot more intense heat and sun, and there isn't a noticeable decrease in life span.

That's how we did ours. No problems at all. Rafters are true 2x4s (early 1900 built), deck is 1" lumber with metal roofing over that. We strapped the rafters with 1x2 at right angles, then spray foamed 4.5" to encapsulated the rafters. We have no snow melt anywhere on the roof, except around the chimney base.

 

[Hddnis]

Hddnis,john i was talking to the insulator and he said yhey make.a finer fiberglass now than they used to so it doesnt get hung up and so on. So it will be better on r value and almost as good on air.Is that true?

Sent from my HTC Hero S using Tapatalk 2

Sounds like he is talking about the new blown/spray type fiberglass and he is right. It is formed shorter and with a spiral to it that help it interweave and form a three dimensional matrix instead of having layers where air can move. Being shorter it flows better before it reaches the desirded density.

When you are blowing into an existing wall the trick is to get the material past wiring, junction boxes, pipes, globs of drywall mud, nail points, all the stuff that is in a wall cavity. The advantage cellulose has is that it flows very well, it is fairly easy to get it to fill all the cavities and cover around all the obstacles. That is why it has to reach a certain density too, to keep it from continuing to flow and settle away from the top of the cavity. The newer fiberglass products are a good compromise and decent insulator with a little practice can get a wall cavity filled up properly. The fact that your contractor knows to use the newer material tells me he should do a good job.



Mr. HE

 

[Hddnis]

Hddnis - If you don't mind me asking, What do you recommend on cathedral ceilings? I ended up having to tear all the insulation (batts) and drywall down b/c condensation on the insulation was soaking through to the drywall. Right now the room is just sitting at the rafters.

OP - Sorry didn't mean to get too much off topic.

I'd be happy to help with some ideas, but I'll need more information on how the building is constructed. If you had some pictures that is good too. Just last fall we repaired a house that had the same problem yours did. He ended up with a new roof, partial new framing due to rot, redone T&G pine ceiling, and new insulation. It was expensive, but he got a really good deal on the house, so he was plenty happy.

Hddnis,

When you took down the insulation did it have vent pannels behind the insulation?
Up against the roof venting air behind the insulation is a must or you get a rotten roof or very damp insulation.

Most standard practice requires some type of venting, but it depends on climate and overall design. I tend to favor the thinking that says "When it doubt, vent it."

Spray Foam! it's the best thing you can do. fiberglass is nothing more than a furnace filter. depending on the depth of your rafters, open cell (1/2 lb) takes more then closed cell ( 1.8 - 2.0 lb) 2lb after 2" will create a vapor barrier. 3" is 96% efficient anything over 4" is wasting your money (ima).

OP - if your getting your crawl space done i would put down at least 6 mill plastic and have it sprayed to the wall to seal, that's a big thing here in Michigan.

I tend to agree on fiberglass being a funace filter. That said though, it has its uses as insulation. Regarding foam, I like it, we install it too, but cost is such that the application needs to require it. For example on a renovation for an old McMansion style house we foamed all the existing 2x4 exterior walls with closed cell. All the new 2x6 exterior walls got spay in cellulose and then blown cellulose in the attic. Doing foam for the entire project would have added $17,000 to the cost without adding any performance to the insulation package. Even if foam could match the price of other insulation I would still limit its use because that stuff is toxic in a bad way. Once it has cured a few days the off gasing drops to levels so low that it is safe. Part of the cost of foam is the PPE the applicators have to wear, full suit, supplied air and peel away face shields.

Ya i looked at closed cell and :msp_scared: it was pricing, (i was looking at DIY kits). I have a bonus room above my garage, so 24 x 24 and it was many many thousands of dollars for foam. :/

So with foam you don;'t have to actually fill the entire truss, area with foam? If after three inches you have a diminishing rate of return, (unless you just meant 3 inches of closed cell).

How the foam is installed depends on your constuction type. I rarely recommend foam for any type of attic or ceiling application simply because of the cost vs. perfomance.



****Hope I'm helping here, lots of people have given good advice in this thread. I'm having just a little trouble keeping track of which projects are which myself.
In short, a trusted local contractor is the best bet for finding a solution. The ability to look at a job in person is huge when it comes to solving a problem or figuring out which product will work best. Insulation is a really good investment, often with huge returns year round.



Mr. HE

 

[upsnake]

Started a new thread, it was getting confusing / Sorry OP

 

[upsnake]

Moved to a new thread.

 

[Hddnis]

I would go with as much spray foam as you can. I put blow in insulation in my shop a few years ago and it gets more drafty every year. I'm going to pull all the cellulose out and get it sprayed. I also have a 100 year old drafty farm house with original windows. so its really drafty too. the walls of the house were blown in cellulose in the late 70s. so all that cellulose settled over the years. the spray foam will pay for itself in 6 years. if I was in your position I would pull all the siding and get the whole house sprayed. I know u just painted it but how many years do u want to live in your house? 30 years? do u want to wish everyday for the next 30 years that you would have done it the right way? do u want to wish u had a warmer house? just my .02

I wanted to address this, it sounds like your cellulose was not properly installed if it is failing. I'm guessing that you bought it and rented an electric blower to put it in?

Please understand I'm not picking on you, just would hate to see you lose your initial investment. We see alot of insulation jobs that fail, including foam, because the installation was not done properly. The reason I asked about the electric blower is because it is hard to get them to work right. Our blower puts out 1200cfm at 12psi, most electric blowers you can rent move about 200cfm and can't achive even 1psi. Properly installing a blown in product is a balance of material flow, air flow and air pressure. Higher air pressure lets the installer pack the material to the proper density, this applies to blowing into a closed cavity or an open attic.

Insulating an old house is fairly simple, and the old standards and methods used in the 70's are long gone. You won't see settling in a modern insulation job, unless someone messes up big time. Start with the windows, then get the attic insulation increased, next do the walls. If the wall cavites are filled already, but settled, they can be "topped up" and brought to proper density. It won't cost much less than starting with an empty wall, but it will cost way less than foam. Instead of a six year pay back you might see a three year or less payback time. Same performance for less investment. Foam ain't magic, it is expensive.



Mr. HE