house insulation

So I recently bought a house, my attic needs insulation (hot in the summer freezing in the winter). My attic has flooring and a cedar chest. The walls are bare and one side of the room has some pink fiberglass insulation. I have some extra insulation that was left by the owner, but have looked at other materials, such as spray foam (which I would hire a pro) or buying a different material. Does anybody have any advice or experience?

There's a guy who publishes an article in our Co-Op electric magazine. Insulation stuff is his expertise. He says that the spay on foam stuff is actually way better than anything else.

Since we're on the topic, what about insulating existing concrete block walls? Add insulation then siding?

This whole building thing is new to me. I come from a cave.

Are you trying to make the attic a conditioned space or save heat for the rest of the house?

we just had a convention at the Borgata and I had a long talk with the guy with the spray on foam. The stuff is -very- cool. It is only an inch or so thick, very solid, and not only stops convection, but also all drafts from inside and out.

One of things he mentioned, it can be sprayed to the underside of the roof instead of the floor of the attic. This makes the entire attic space into a trapped air space to keep the temps inside the house steady

If price is an issue, stop talking about foam.

You can spray 1" on, but it won't meet code. It will offer about R-6.0. Most of the country requires R-38 in the ceilings. You need 6-7" of spray foam to meet code.

You need to clarify a few things before anyone can offer advice.

trigun7469 wrote: So I recently bought a house, my attic needs insulation (hot in the summer freezing in the winter).

Did you mean the ATTIC is hot in summer/ cold in winter? That's what it should be. Or did you mean the HOUSE?

Secondly, do you want to pay to heat the attic? Do you need the floor in the attic? Are you looking to improve a bit, or get serious? Have you had an energy audit?

"Cold in the winter" is not much science. The biggest payoff in that might be draft sealing the windows.

How much insulation is there now? "One side of the room has pink stuff" doesn't tell us very much. Is the area fully covered, without gaps or voids? How thick is the existing? Is there insulation under the floor?

If the space is uninsulated, then yeah, you need insulation. But if it is under-insulated, you need to tweak it.

The biggest payoff in energy savings and comfort in a remodel is usually not insulating the attic.

Pics would help too. Spray foam is cool as a sealer and for getting a good insulator when space is at a premium. 7" of the stuff when you can have room to use blown in or batts is excessive.

Blown in cellulose is your best bet to start, make sure you incorporate attic baffles on every cavity. R30 to R40 is a good start, beyond that it is no longer cost effective, for the cost of the extra insulation you could start attacking other inefficient building components. I suggest starting with a blower door test/energy audit

If you want to go past that you could start researching passivehouse, enerphit, energystar, and other building science/energy focused specifications as detailed all over the web. Green Building Advisor is a good place to start. If your interested I can elaborate further with respect to retrofits.

Derick Freese wrote: Since we're on the topic, what about insulating existing concrete block walls? Add insulation then siding? This whole building thing is new to me. I come from a cave.

Perhaps.

In FL, insulation on the exterior of the building would probably help, but there are some caveats.

First off, termites like a lot of different insulation. So, it needs to be well protected from the elements, and termite shields installed on the bottom edge. I would also use treated insulation.

Vapor barrier paint on the exterior may do more than you realize. It slows the absorption of moisture from the warm exterior air into the masonry, keeping the interior humidity levels lower, which will effectively feel cooler.

Before I spent the money on insulation and siding, I'd use vapor barrier paint and install a dehumidifier.

slopecarver wrote: Blown in cellulose is your best bet to start, make sure you incorporate attic baffles on every cavity. R30 to R40 is a good start, beyond that it is no longer cost effective, for the cost of the extra insulation you could start attacking other inefficient building components. I suggest starting with a blower door test/energy audit If you want to go past that you could start researching passivehouse, enerphit, energystar, and other building science/energy focused specifications as detailed all over the web. Green Building Advisor is a good place to start. If your interested I can elaborate further with respect to retrofits.

I am a certified HERS Energy Rater.

Some of the info you are offering is contradictory. Attic baffles and blown-in insulation on the ceiling envelope is not in keeping with the newest building technologies recommended on some of those websites.

Don't get me wrong... blown-in cellulose is often a good idea, but in of itself it is not necessarily your "best bet to start", unless it is part of the overall building energy design/ plan.

So, the first question is, will the attic be conditioned or not? If it is conditioned, blown-in cellulose is a terrible idea.

If it is not conditioned, and there is already some insulation on the ceiling, blown-in is likely the most cost effective (but not the best).

In reply to slopecarver:

BTW, blown-in cellulose has an R rating of about 3.6- 3.8 per inch.

The R-40 you are suggesting would require 11" thick.

It is highly unlikely he has 11" of space under the existing floor. It's often tough to find that much space in a retrofit. I'd bet his floor joists are 7.5" thick.

Like I said... we need more info.

In reply to SVreX:

I stand corrected and I agree, more information is necessary. Can you elaborate on the most current building science attic retrofit methods? Assume unconditioned, no floorboards.

Please see pictures below, right not it is used for storage, I thought maybe in the future of being a room, we have a boiler system so the heat and air conditioning would have to be electric. I no nothing about construction or code, but thought it might be a good selling point to call that space a "room" instead of a attic and perhaps when I have kids it might be another sanctuary.

So, are you trying to insulate the floor to save on current energy bills, or insulate the attic for a future habitable space?

slopecarver wrote: In reply to SVreX: I stand corrected and I agree, more information is necessary. Can you elaborate on the most current building science attic retrofit methods? Assume unconditioned, no floorboards.

I guess the best I can offer is that modern building science is starting to recognize the building as a system, and the need to design the insulation as a part of the entire system.

There is no one-size-fits-all solution.

You can't break it down to a single component and say "what's the best insulation", or "How much R value".

Thermal transmission, heat flow, air leakage, fenestration, humidity, duct system design, air exchange, combustion air, vapor transmission, occupant load, delta T differential design, and efficiency of the heating system are all part of modern building science.

So, for example...

Batt insulation can offer reasonable thermal resistance, but it sucks at controlling air leakage. Cardboard works better. So, a well insulated house may feel drafty, and therefore cold.

It also acts like a sponge if exposed to moisture. So if it is installed without a moisture barrier and the dew point is within the physical limits of the batt insulation, it will absorb moisture, which will negate it's thermal resistance (because water has almost no thermal resistance).

It's an overall design.

Having said that, the answer to your question is that sprayed closed cell foam is often a superior product, at a cost that is prohibitive. It controls both thermal transmission and moisture transmission, but it's superior performance in sealing air leakage is probably what makes it feels the most outstanding (it's not the R-value). Most people can't afford it, and it's cost is high enough in a retrofit that it almost always has an exceedingly long payback period.

Blown-in is MUCH cheaper, and can be added on top of existing. It won't draft seal or moisture seal, but it will add thermal mass, and can be installed at an affordable price. Generally will lower heating bills, but often doesn't change comfort level (because draft sealing is not addressed).

Batts have similar performance to blown-in, at a higher price.

The biggest bang for your buck in a retrofit is always draft-sealing first, including duct sealing, then moisture transmission controls. To do this well, the very first dollar spent should be an energy audit that includes a blower door test and duct blaster (both before and after modifications). That's IF you want to be scientific about it. If not, dump some insulation in your attic.

Improved windows are by far the best investment in new construction, and the worst in a retrofit (from a pure cost analysis perspective).

Those are generalities. YMMV.

Let me shorten my answer...

Asking "What is the best attic insulation" is a little like asking "What are the best tires".

It depends!

These are the people I was talking about with their foam. It's pretty impressive stuff

Lapolla Industries

SVreX wrote: So, are you trying to insulate the floor to save on current energy bills, or insulate the attic for a future habitable space?

Is there a significant price difference?

I would look at it this way. If you insulate the attic for future habitable space, that open area becomes a "dead air" space that will help to insulate the rooms below

SVreX wrote: To do this well, the very first dollar spent should be an energy audit that includes a blower door test and duct blaster (both before and after modifications). That's IF you want to be scientific about it. If not, dump some insulation in your attic.

SVreX,

How would I go about finding someone qualified to provide us with an energy audit? Our utility rates (in our county) are among the highest in the state currently and getting ready to go up even more, thanks to a pretty bad deal struck with an outside company to construct a very expensive biomass plant. I think I need more insulation, among other things, but think your advice to start with an audit is the best course of action.

Try contacting your utility company. They may have agreements with contractors who do this sort of service.

I've got the sprayed in foam in my old balloon framed house. I can offer a few words of experience with it.

How well they blow it in dictates how well voids are filled. In my case, various spots have several inches to several feet missing.

Every plug they put in on an outside wall will show, and many will pop out. They also swell differently, splitting the siding.

Your stud detector will see the insulation as a solid, and never find a stud again. Not even the fancier ones with a view screen. Only nail detectors will work.

You cannot run anything through it without ripping it up. You're pretty well done when it comes to running another wire or pipe.

Contrary to the proclamations of the vendors, mice and vermin will burrow through it and make nests.

It does work well as an insulation, and as a noise barrier.

trigun7469 wrote:

SVreX wrote: So, are you trying to insulate the floor to save on current energy bills, or insulate the attic for a future habitable space?

Is there a significant price difference?

Yes. Sort of.

It's a fundamental design choice.

The first difference is the area. You would have approximately twice the area of insulation by the time you do the gable walls, etc.

The second difference is bigger.

You will be treating the attic as conditioned space. So, it will become a buffer zone, but it also increases the volume you need to heat. It's another room.

But it also changes the ventilation characteristics of the structure.

Your house is currently designed for air to flow reasonably freely in the attic. This is important to keep the insulation dry. The "back side" of the insulation (top) is ventilated, and the bottom is against a draft seal (the ceiling). That's the way batt insulation is supposed to work.

If you move batts to the roof, there is no longer air space above it. The damp insulation will be in contact with the roof deck, which can rot it.

So, you will have to lower the insulation to create air space (baffles). Carpentry and framing work.

But then, your batts will not be against a draft seal surface (like a drywall ceiling). Batts don't work that way, so you will have to consider dry walling the ceiling the real any benefit from the insulation.

Then, you will have to seal the rest of the attic (because it would now be part of your living space. Not sealing it would be like leaving a window open).

The alternative would be closed cell spray foam the entire attic. That would seal everything nicely, and not have ventilation if moisture problems. But the cost is 3-4X batts, and it is not DIY friendly.

So, yes, there is a significant price difference.

Do you have any ductwork in this attic?

Other than that.. SVreX covered it well.