Fiberglass Batt vs. Blown-in Insulation?

[Iplayfarmer]

I'm to the stage in my basement re-model where I'm planning insulation. I had a guy quote me a price on blown in insulation that is within pennys of the cost of buying the material for batt insulation.

What's the collective wisdom from TBN? Is the blown in cellulose stuff as good as the fiberglass batts? Does it settle over time?

I'd like to go with the blown in stuff because the guy would do all the work. If I get batts then I'll have to put it in.

 

[PointyHairedBoss]

My personal preference is rock wool insulation (called Roxul here in Canada). It comes in batts like fiberglass but is more rigid.

The theroretical R value is a little higher than fiberglass but in practice it is much better. When you fill a stud space with fiberglass, it often bunches up where it touches the studs, wires, junction boxes etc. & you lose some of the insulating value because of those voids. Roxul is quite stiff by comparison & you cut it with a serated edge bread knife to go around obstructions. For example, if you have a wire through the stud space, cut the back of the batt about half way through & fit it over the wire. It stays quite stiff & completely fills the stud space. If you have an electrical box, cut out a square of the insulation & you will be tight all around the box.

I don't like blown insulation because it settles over time.

 

[Zick]

Both will settle but cellulose does more than fiberglass. Cellulose also cost quite a bit less than fiberglass.
I think cellulose does a good job and cost less even if you have to add a little more to make up for the settling.
We have blown in fiberglass in our new house but I'm thinking of topping it off with cellulose later on.

 

[Scooby074]

My personal preference is rock wool insulation (called Roxul here in Canada). It comes in batts like fiberglass but is more rigid.

The theroretical R value is a little higher than fiberglass but in practice it is much better. When you fill a stud space with fiberglass, it often bunches up where it touches the studs, wires, junction boxes etc. & you lose some of the insulating value because of those voids. Roxul is quite stiff by comparison & you cut it with a serated edge bread knife to go around obstructions. For example, if you have a wire through the stud space, cut the back of the batt about half way through & fit it over the wire. It stays quite stiff & completely fills the stud space. If you have an electrical box, cut out a square of the insulation & you will be tight all around the box.

I don't like blown insulation because it settles over time.

Yes but Roxul is SO MUCH money. Way more than FG. Good product though. If im at roxuls price point, im going with spray in PU foam. way tighter.

 

[jonyyuma]

My personal preference is rock wool insulation (called Roxul here in Canada). It comes in batts like fiberglass but is more rigid.

The theroretical R value is a little higher than fiberglass but in practice it is much better. When you fill a stud space with fiberglass, it often bunches up where it touches the studs, wires, junction boxes etc. & you lose some of the insulating value because of those voids. Roxul is quite stiff by comparison & you cut it with a serated edge bread knife to go around obstructions. For example, if you have a wire through the stud space, cut the back of the batt about half way through & fit it over the wire. It stays quite stiff & completely fills the stud space. If you have an electrical box, cut out a square of the insulation & you will be tight all around the box.

I don't like blown insulation because it settles over time.

Pointy, I haven't seen any rockwool down here in years. It is hard to work with, and if i remember it irritates the skin and eyes.Fiberglass,celluloid and zonolite, plus urethane spray foam here. I used celluloids, if you blow it over fiberglass batts, yes it will compact down the batts. It also filled in the spaces where the glass was not consistant in the attic. I did notice that mice will go right on thru all of it. I buy a fresh box of bait every winter to feed them.My utility bill tumbled after I blew the attic, therefore it was very worth while. I am now laying foilbacked jacket up on top of all my insulation, to reflect heat in the summer,per new local energy regulations.Jy.

 

[PointyHairedBoss]

Yes but Roxul is SO MUCH money. Way more than FG. Good product though. If im at roxuls price point, im going with spray in PU foam. way tighter.

I did our cottage (future home) with Roxul - R21 walls, R35 roof/ceiling (no attic) 6 years ago. It's not a large building - 1 1/2 story, about 1600 SqFt. total. Additional cost over fiberglass was about $1000. It does a better job than fiberglass so I thought the long term fuel savings would pay. PU foam was way more above the cost of Roxul but I used it for the basement/crawl space because it does such a great job of sealing all the nooks & crannies between the joists.

 

[PointyHairedBoss]

... It is hard to work with, and if i remember it irritates the skin and eyes. ... .

I find the opposite on both points. For me, Roxul is easier to work with. And I find fiberglass is itchier. Of course you should use a mask when installing either - bad stuff to breathe.

 

[jonyyuma]

Exactly, right, breathing anything but clean air is bad. I don't remember which seems to have been the worst to install. I do have some very old rockwool installed over my garage. It does not seem to be doing anything but making it warmer? Jy.

 

[Scooby074]

I did our cottage (future home) with Roxul - R21 walls, R35 roof/ceiling (no attic) 6 years ago. It's not a large building - 1 1/2 story, about 1600 SqFt. total. Additional cost over fiberglass was about $1000. It does a better job than fiberglass so I thought the long term fuel savings would pay. PU foam was way more above the cost of Roxul but I used it for the basement/crawl space because it does such a great job of sealing all the nooks & crannies between the joists.

I talked to the Roxul guys at a show and i think they said something like 30- 40% more then FG. For somewhat limited benefit. (they tried the whole Fireproof and mold proof "what about your family" line on me too. I wasnt impressed). Id like to support them. If the premium was 5-10% maybe

 

[Iplayfarmer]

...I think cellulose does a good job and cost less even if you have to add a little more to make up for the settling.
We have blown in fiberglass in our new house but I'm thinking of topping it off with cellulose later on.

This is going into finished ceiling in the basement... i.e. It will be encased in sheetrock. I won't have the opportunity later to add a little more.

Since you mentioned basement, I assume that access is good so I would go with DIY fiberglass batts.

Everything is torn out now. Access is great. I already have the r-13 for the walls as I got it surplus. All I need is the basement ceiling. What has me confused right now is that I can get the blow-in stuff installed cheaper than I can buy the batt to do it myself. That has me wondering what the trade-offs are to the cheaper blown in insulation.

 

[jimmysisson]

Applied right the blown cellulose will outperform the batts quite a bit. As someone said, the batts are hard to fit tight around stuff. Little gaps equal big heat loss. Floors aren't demanding, but since you can save the labor, go with the blown.
Thing is, you'll never have good access to your main floor again without a big mess. Are you SURE you'll never remodel your kitchen, half bath, or family room again?
Jim

 

[Ranger Rick]

This is going into finished ceiling in the basement... i.e. It will be encased in sheetrock. I won't have the opportunity later to add a little more.

If this is going in the basement ceiling why are you going to the expense of insulating it. The rooms above the basement are heated so you will not save much on energy. Now I could see insulating to keep noise down if that is a problem. Rick

 

[Travelover]

If this is going in the basement ceiling why are you going to the expense of insulating it. The rooms above the basement are heated so you will not save much on energy. Now I could see insulating to keep noise down if that is a problem. Rick

If sound reduction is the primary objective, you'd be better off with super good sealing and two layers of 1/2" drywall.

 

[Iplayfarmer]

The point of insulating the ceiling is not for energy savings, but more for comfort. This is an old, rickety hose, and I hope that insulating the floor/ceiling will keep the noise down. The other thing is that the basement is cool in the summer. I hope that it will be even more cool if I have insulation in the ceiling keeping the heat from radiating down.

 

[AHNC]

The point of insulating the ceiling is not for energy savings, but more for comfort. This is an old, rickety hose, and I hope that insulating the floor/ceiling will keep the noise down. The other thing is that the basement is cool in the summer. I hope that it will be even more cool if I have insulation in the ceiling keeping the heat from radiating down.

I'm with the other fellows asking why insulate the ceiling. A point I'd make for your "old Ricketty" is that you want to be very sure that all of your electrical, plumbing and future needs are squared away before you put up that sheetrock, especially the ceiling. I sell plumbing/heating/AC equip/components and see so many installations where people two-block themselves with the finished basement ceiling. Also, keep in mind that in a basement, as you isolate it from the hot upstairs you are going to have issues with moisture/humidity in the summer months. So, my question is, how are you going to condition the space and handle the humidity? i would suggest that you want to isolate the system from the main house, if possible.

 

[Carl_NH]

I agree with access to the space and suggest standard batt insulation 6" with a dropped ceiling for access. The panels can be easily removed/replaced and provide access to put in wiring, speakers, fix a plumbing issue and they also have more sound deadening ability than sheetrock.

 

[LD1]

I hope that it will be even more cool if I have insulation in the ceiling keeping the heat from radiating down.

Doesnt heat rise:laughing::laughing::laughing::laughing:

The reason you can get the blown in cheaper is because the material cost only about half of batts.

My main concern though is if you go the blown in route, how is he going to do it??? Are you going to be there putting up sheetrock as he is blowing in??? or are you going to have all the sheet rock up except a few at the ends?? If so, how can you/he ensure that the blown in is making it all the way to the other end and filling all the voids?? and how do you plan in insulating above the last few panels??

Blown in insulation works the best when you can do it from the topside. I did the ceiling in my garage with blown it but I did it from the topside before I put the floor down for the loft. The only reason I used blown in is because it was far cheaper than bats. And most places like lows and menards give you the blower for a day for free if you spend $100 on blown in.

But for a basement, If you insist on insulating it, I would go with the bats.

 

[Travelover]

I agree with access to the space and suggest standard batt insulation 6" with a dropped ceiling for access. The panels can be easily removed/replaced and provide access to put in wiring, speakers, fix a plumbing issue and they also have more sound deadening ability than sheetrock.

I agree except the statement about the sound deadening. Mass is king for sound deadening.

 

[Iplayfarmer]

I'd love to go with a dropped ceiling like Carl suggested, but my ceiling is only 7' high. It's just not an option for me. What I'm doing instead is running any wire, plumbing, etc. that I can think of now. I have 3,000 feet of Cat6 and Coax. I've put in almost a thousand feet of 12/2 romex. We completely re-did the HVAC, and I replaced every pipe in the whole house. In addition, I've doubled up some of the joists and I'm planning to spot treat any upstairs floor squeaks by raising the floor and gluing from underneath with subdeck adhesive. I admit there's still a risk of obsolescence later, but I have to work with what I have.

To answer LD1's question, the guy was going to net the joists and blow it in on top of the net. We'd then sheetrock over the net. This guy sells both batt and the blown in stuff, and the one thing he pointed out is that with all the wire and pex running through the joists, there are a lot of areas where the batt will be crushed.

Thanks for all the input so far. It's helping me better evaluate the pros and cons.

 

[LD1]

To answer LD1's question, the guy was going to net the joists and blow it in on top of the net. We'd then sheetrock over the net. This guy sells both batt and the blown in stuff, and the one thing he pointed out is that with all the wire and pex running through the joists, there are a lot of areas where the batt will be crushed.

Thanks for all the input so far. It's helping me better evaluate the pros and cons.

If you aren't worried too much about the insulation value, and are mainly concerned with sound deadning, I wouldn't worry too much if the batts get crushed in a few areas.