Insulation questions

txriverwillow · Post by **txriverwillow** » Sat Jun 17, 2006 11:04 am

We are going to add insulation in our attic floors. In a couple of years, we plan on building into the attic, but for the here and now, we just need to add insulation.

1. Which would you recommend in the attic floors - insulation blankets (typical fiberglass roll out type insulation) or blown insulation?

2. Is blown insulation more likely to spread a fire than fiberglass insulation?

It is about half the cost to do blown insulation so I'm wondering what the drawbacks to it would be.

TIA

TDWEB · Post by **TDWEB** » Sat Jun 17, 2006 3:38 pm

Blown insulation may actually smolder, but it really does not burn, they have added a fire retartdant to the cellulose. If you are intending to remove the insulation when you finish the attic, use the fiberglass as it can be removed and then reused to insulate the rafters. The blown will have to be removed by vacuuming it out.

Danno · Post by **Danno** » Sun Jun 18, 2006 12:38 am

TDWEB wrote:If you are intending to remove the insulation when you finish the attic, use the fiberglass as it can be removed and then reused to insulate the rafters. The blown will have to be removed by vacuuming it out.

I'd say that's the selling point of the fiberglass over the blown. If you REALLY do intend to finish it sometime, you just re-use it and you'll save yourself some time and money in the long run. Of course, if you are like me, you always plan on having more money in the future than you do now, so the cheaper expense for the now seems like a do-able thing and then you'll have forgotten that expense when you do the future project. Never do really seem to have a larger "bank" in the future though, so save a few bucks in the long run and roll out the fiberglass...

TDWEB · Post by **TDWEB** » Sun Jun 18, 2006 7:09 am

Danno,

I understand about the money part, my wife and I are S-L-O-W-L-Y restoring a 1915 4-square here in northern Indiana. I must tell you that in all honesty, the insulation upgrade, add-to, is the cheapest and quickest return for the dollar spent of any home improvements out there. Quite often it will pay for itself in one (1) heating season. It also pays if you run A/C too. The most importanat thing is to have it done right.

MattStiltner · Post by **MattStiltner** » Mon Jun 19, 2006 12:48 pm

Fiberglass batts.

Reusable.

Period.

Otherwise you're paying for insulation twice. Seems kinda silly.

On that note. I got some R-19 to shove in some flooring somewhere, but I'm too darn sick to do it

txriverwillow · Post by **txriverwillow** » Mon Jun 19, 2006 1:52 pm

Ok this might sound like a stupid question (maybe even one that my hubby would know but I won't see him for several days) but wouldn't it make sense to leave the insulation in the attic floor when we build up there and just add more insulation to the ceiling at that time?

Danno · Post by **Danno** » Mon Jun 19, 2006 2:20 pm

txriverwillow wrote:Ok this might sound like a stupid question (maybe even one that my hubby would know but I won't see him for several days) but wouldn't it make sense to leave the insulation in the attic floor when we build up there and just add more insulation to the ceiling at that time?

Yes and no. You don't necessarily need to insulate the whole floor of the attic once it's a room. you will have to insulate the floor of the hip-space so that the cold air doesn't circulate into the area under your floor though. If you see one of my other threads around here you'll see that I'm pretty much thinking of leaving my blow in insulation right where it is as I finish a room. Mine's just a closet, but it'll make good sound insulation, too. only other consideration is whether or not you put some sort of vapor barrier there, that can effect how you can use it later.

TDWEB · Post by **TDWEB** » Tue Jun 20, 2006 5:39 pm

Personally,

I would not leave the insulation in the floor, primarily due to moisture retention. It may start to mold some. It would be better to remove it, and use it in the rafters. The idea being to build an envelope of the house, including moisture barrier in the rafters. Also, a substantial amount of heat will find its way up there through the floor, and with insulation in there, it may in fact cause you some unnecessary heating problems for the winter months. Just make sure you insulate the rafters very well. Something you might consider is just insulating the rafters now, perhaps with a glue bound blown insulation, or even the expanding foam that is sprayed in, then the job is done, and when you are ready to finish the attick, that part is done, and you move directly to rocking the rafters instead of doing double duty

franklyspeaking · Post by **franklyspeaking** » Tue Jun 27, 2006 11:13 pm

I would like to dispell the notion that thermal insulation has much, if any, sound attenuation ability. It takes mass to stop sound and thermal insulation is not heavy enough to be of much use. However, many a cubic foot of insulation has been sold on the premise that it sound proofs a wall. If you want sound attenuation, you need to double or triple the drywall thickness. Case in point, the office I work in has a business on each side. The business on the left has three thicknesses of 5/8" sheetrock between our offices for fire spread prevention. The office on the right has one thickness. Guess which direction we hear the neighbors?