Attic/Ext. Walls Insulation in Austin (real estate, loan, how much)

[l0ll1]

Hello All,

What is the recommendation for Austin new house for insulating Attic and Exterior walls? My builder is putting:

Attic: R-30 12" Blown Fiberglass insulation.
Cathedral ceiling: R-19 Fiberglass Batts.
Band Joist: R-13 Fiberglass Batts.
Radiant Barrier, and Ridge and Soffit Venting.
Ext. Walls: R-13 Fiberglass Batts I think.

1. Is this enough?
2. Is cellulose insulation in attic a good choice? I read about settling and moisture retention issues with cellulose.
3. Is it advisable to go with both fiberglass batts and cellulose in attic?
4. If I put cellulose, will I be loosing usable area in attic?

Any info/suggestions would be a great help. Thanks!

[musicman107]

Originally Posted by l0ll1

Hello All,
What is the recommendation for Austin new house for insulating Attic and Exterior walls? My builder is putting:
Attic: R-30 12" Blown Fiberglass insulation.
Cathedral ceiling: R-19 Fiberglass Batts.
Band Joist: R-13 Fiberglass Batts.
Radiant Barrier, and Ridge and Soffit Venting.
Ext. Walls: R-13 Fiberglass Batts I think.
1. Is this enough?
2. Is cellulose insulation in attic a good choice? I read about settling and moisture retention issues with cellulose.
3. Is it advisable to go with both fiberglass batts and cellulose in attic?
4. If I put cellulose, will I be loosing usable area in attic?
Any info/suggestions would be a great help. Thanks!

Speaking as a licensed real estate inspector...
Central Texas is "zoned" as minimum of R-30 by the International Residential Code. Most current, new construction install R-30. Some buyers are opting for upgrade to R-38, in anticipation of news that electricity rates are expected only to rise over next years...not get any lower. My own guess is that upgrading to R-38 in attic will pay for itself over a number of years... not immediately...too many variables (including one's comfort level in the home; i.e. some set thermostats at 65 degrees, others set it at 75/use ceiling fans; some have many children going in and out of home, leaving doors open in summer, etc.).
R-13 is also considered the norm for exterior walls. Variables there include: shade trees around home? how many windows on south and west sides...etc.
I haven't seen a prob with moisture retention with any of new insulation materials...attics here will easily reach 130 F... you mention combination of radiant barrier roof decking, soffit venting (hopefully "continuous soffit'), and ridge venting...all a very good combination for ventilation and avoid moisture retention.
RE: attic insulation..might consider asking builder how much add'l $ for upgrade to R-38...if you plan to be in the home for more than a few years...my guess that "rolling in" some extra $ NOW into orig. construction would pay itself back in heating/cooling costs...
Reconsidering, and upgrading to R-38 at some time in the future would be a questionable proposition....insulation material costs will be higher, plus you would have to pay for installation/labor...would increase "payback" time...doesn't cost any more labor to install R-38 during orig. construction than to install R-30 now.
RE: losing attic space: if attic structure is of "web-truss/engineered" design...you won't be able to use much space in attic for storage...
if attic struct. is "conventional", then you will have add'l attic storage space.
Hope that's of some help to you.

Respectfully yours.

[phxdouglas]

I have an old home, and I hate the blown fiberglass insulation! It is dirty, it sticks to me when I crawl around, and it falls on my face when I have to open the ceiling for a new light or ceiling fan.

I'm looking for someone to remove this garbage, and I'm getting spray-foam instead.

[AtticCare]

The question was about a new home, which means they probably wont be replacing fixtures anytime soon, or in the attic at all. Cant figure out why you spend so much time there phx??? Although you may hate blown fiberglass, there is a reason it is the most popular choice....it will actually pay itself off, unlike foam(5 times the cost) I went r-42 and my bills were excellent! I think there is a calculator at DOE or energy star webpage. Where they also explain Cost/Savings Most people arent willing to spend 80 bucks a month to save 25!

[texdav]

I thnik he has a good point on the BLOWN fiberglass.The contined fiberglass mostlyt eliminates that problem. High heat climates need good attric circulation and they problem can be bad. I can't imagine a preson npt going into there attic unless they pay others several times a year.

[IC_deLight]

If you have any recessed lighting planned (those lights in a can where the can extends into the attic) you might want to be a little careful about covering up the can with a blanket like this - it causes some of those fixtures to thermally overload during extended use.

Also you might consider hiring an inspector (no I'm not an inspector). Although you contract for a particular grade of insulation, the crews that blow the stuff in your attic (particularly in mass-produced housing) might just see it as another one of 100 homes they are blowing insulation into. You might not be able to tell the difference yourself. Consider confirming what they're going to install BEFORE, and inspecting/confirming AFTER the job is done.

[FalconheadWest]

The figures you posted are very typical. Have you thought about a radiant barrier on your roof to help the insulation bring down the electric bills? If you haven't built yet, I would add it as it will definitely pay for itself quickly. Otherwise, you can add it afterwards, but it's a paint-on and not as effective as the built-in kind.

[FalconheadWest]

My bad, you did say there was a radiant barrier... then you should be good to go.

[AtticCare]

Last home I owned for 5 years, bought it, blew in fiberglass, and never returned to the attic. (storing stuff in your attic] If you going to put it in the attic, just throw it away or sell it, you obviously dont use it enough to justify owning it. Attics usually arent designed for storage or walking/living in. I have seen so many customers concerned about storing stuff up there, then 5 years later they are moving that same unopened box from that house to another one, just get rid of it!

[Trainwreck20]

Attics usually arent designed for storage or walking/living in. I have seen so many customers concerned about storing stuff up there, then 5 years later they are moving that same unopened box from that house to another one, just get rid of it!

Ahh, but we are in ours pretty much monthly . We decked the whole area over the garage and built some shelves, too, so all our occasionally used tools are up there, as well as the heat-resistent holiday stuff - Christmas lights, metal ornaments, etc. Our camping stuff is up there, too, and the card table/chairs for when we have a crowd over for something. Hmmm...what else...the baby stuff, which we are pulling down/putting up a lot more than we thought we would - it is forever being loaned out to someone with a new baby. Because we have built-out the attic somewhat, it is pretty easy to get up there and get stuff down.

On the other hand, the area over the garage is not insulated, so it was relatively easy to deck and there was no worry about compressing or damaging insulation. To get back to the AC unit, we have a wooden walkway made out of 2x4s across the piles of insulation.