R-30 Fiberglass

[Clayton]

I just moved into a new home where the builder installed R-30 in the ceiling truss area. I had requested R-30 as a minimum. After looking at their work, the electrical wiring is woven in and out of the insulation to where we probably only have R-11 or less in several locations. You can tell by the snow melt on the roof that it is poorly insulated too. What is the best way at this point to improve this situation?

But you know I think they might have saved them selves a few bucks on their wire material!

[Ben H]

What does "ceiling truss area mean"? What type of insulation was used (blown, batts, etc.)

Where did you come up with the new R-11 Number?

[kurt]

Got a pic?

Shot from the hip, the only likely way to get any decent coverage in a truss assembly is with blown in loose fill. You don't want "fluffy" insulation; lots of convective heat loss through the fluffy stuff. Density is important.....cellulose is both cheap and higher density.

[Ben H]

Another important thing is air sealing. If you have lots of holes between the conditioned living space, and the attic, you'll lose a ton of heat. Recessed lighting can be a huge one.

[SNations]

Your information says you're from Charleston, WV.

Why did you request R-30 as a minimum? According to the International Energy Conservation Code 2009, Table 402.1.1, for your climate zone the minimum ceiling insulation R-value is R-38. This minimum applies to the entire state of West Virginia.

[randynavarro]

Batts are a poor choice in attics. It's impossible to fill all voids and get it installed perfectly.

Kurt mentioned it: blown-in cellulose works best; unless you can afford to do spray foam.

[Clayton]

I am sorry if I was not clear. I had R-30 batts installed because I know I will be working on some wiring issues soon and thought that would be neater. The current insulation is compressed in areas and there are cracks between some of the batts. I thought I would try and run more unfaced batts in the opposite direction of the joists but am not looking forward to the job. There are can lights too that will have to be dealt with. What do the pros think?

Thanks for feed back.

[kurt]

Running batts in the opposite direction would be almost impossible; you've got all the truss webbing in the way.

If you want the insulation to work, use loose fill.

Trying to take everything out of sequence to accommodate some electrical work isn't how to do it.

Work in sequence. Finish the electrical work, then insulate.

[Marc]

Take a look at this document:

Download Attachment: Batt installation.PDF

548.36 KB

Highlight any details that the builder missed, then decide if you think you've enough to get him to pull out all batts and install loose fill.

If you know the manufacturer of the batts, get a copy of the install instructions from them and go over it with your highlighter.

Marc

[David Meiland]

You're never going to have more than a mediocre attic with batt insulation. Blown-in cellulose is a better choice, and once they are there, it can easily to be installed to R-60 at minimal extra cost, with substantial savings down the road (since you had the house built, I assume you plan to stay there and can gain the benefit of extra insulation over the years, especially if energy prices increase). I would remove the batts, sell them on craigslist, do all the air-sealing you can around pipes, wires, etc., figure out a way to deal with the can lights (do some internet reading on this), figure out how to deal with ductwork if any, get the attic access weatherstripped and insulated. This is a weatherization /retrofit / home performance project, and there is a lot of internet reading available on it. Here's one place to start: http://apps1.eere.energy.gov/buildings/ ... report.pdf and here's another http://oikos.com/library/airsealing/checklist.html