I have a few questions about old insulation. My house was built in the mid 50’s. They used rock wool insulation in the attic, none in the walls, typical. The house shows a constant dust on the floors since I installed hardwoods.
With carpet your not aware of how dusty your house is, I assume. Or, as I ponder is the attic insulation drifting down into the living area. Where is all this dust coming from.
The exterior is all stone and I’ve installed and sealed new windows. I’ve removed 2/3’s of the exterior walls sealed, insulated and rerocked. I’ll finish the rest this summer.
My thinking is to super insulate the attic but wonder if I should vacume out all the old insulation first. The benefit I feel is I’ll get access to all holes and air infiltration. Not to mention my thinking that the old insulation is flat and by loosing it’s fluff over the years has a minimal insulative value. And that this will remove the dust source?
So… Could the house be getting dusty from old attic insulation?
and would you vacume out an old attic and reinsulate with new?
or Should I just get out the vacume and drink a beer?
Edited 2/17/2009 9:58 am by jagwah
Replies
I doubt that the dust in your house is from your attic. If my memory is correct most of the dust in ones home comes from your skin shedding dead cells.
I think that sealing the holes to stop air infiltration (or is it exfiltration) is a good idea, However, I think that you will get the most bang for your buck by blowing in cellulose to R-60. Blown cells is better that glass for stopping air movement.
Thanks.
The skin cell idea is scary. From the looks of this dust and at the rate we vacum I should disappear in about another month.
jagwah..... here's a link to a pretty common sense discussion of interior dust
one point he makes is that the average vacumn cleaner picks up things but most of the dust by-passes the filters and gets blown right back into the room
a central vac with discharge outside of the living space takes care of a lot of this
http://www.askthebuilder.com/597_Dust_Control_in_Homes.shtmlMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
I always thought that our vacumes filter might allow fine dust to escape.
Still interested about the removal benefit and replacement of attic insulation as well.
i wouldn't remove it... i'd blow right over it with cells
maybe build a catwalk so you can have future access to anything you may need to get to
i assume yo have plaster / drywall ceilings .... so the dust in your attic insulation would have no direct way of getting into the living space
also... if you go into the attic... i would bet you could do a dust test easy enough..
tape some black plastic horizontal.. and go back in a week and take a lookMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
There are likely lots of sources for dust. We renovated and added on to our '49 vintage house. We're cleaning more often since, but I think there's also less dust. I attribute it to new (not nearly as leaky) ducts (old ones were in the crawl) and a lot of air sealing besides in the attic.
The gold standard is to get a blower door test to see where the leaks are. FWIW, I shot foam in the gap between the flooring and framing at the perimeter in every room b/c we have shiplap subfloor and not great insulation coverage in the crawl (project on the 'one of these days' list). I also added foam gaskets to every electrical box in the exterior walls.
I really like the idea of cellulose for the attic, but only if you're really going to be done afterward. If you may break into the ceiling again beyond small penetrations, I think it would be a Gigantor PITA mess.
I'd replaced our attic insulation a couple years before remodeling. Some previous-owner-yahoo had dumped bushels upon bushels of styrofoam peanuts up there. You can probably rent or pay someone to remove easier. But I can testify that it's DIYable too- I used a shop vac sucking a (heavy duty, rigid) trash can and then a flex dryer duct to a piece of rigid duct and a reducer to suck into the can. It worked well, but there are very few things I've done that were less fun. I pulled something like 30-50 30-gal bags of the stuff out over several weekends.
Our house was built n '59, has ceilings that are drywall with plaster over it, and rockwool insulation in the attic. We're lucky enough to have some insulation in the walls, but it doesn't seem to be quite as thick as te stud bays.
I agree with others--you probably aren't getting dust from the atic (unless it is entering your HVAC system up there--no return air or air handler in the attic, right? If there is, seal up everything tight). I blew 12" of cellulose over my rock wool, and it made a big difference in our heating bills. Frankly, the attic is dustier now than it used to be, but I haven't noticed any difference regarding the dust in the house. Removing the rock wool would be a PITA, and no matter how squished t ism it's still doing you some good. I'd caulk up the air infiltation routes up there, but put the rock wool back in place. before blowing int he cellulose.
One other thing-how's the vapor barrier in the ceiling? Now might be the time to address it, if it isn't good. Depending on the situation, two coats of Zinnser BIN on the ceiling followed by paint can sometimes be an easier approach than addressing the problem from the attic side.
I agree that clearing out the attics old insulation would be a PITA but I was curious if this was practicle and who's done and if there's any info on this.
I don't mind a PITA,(I'm married), but I don't want to consider it of there's no data it's smart and effective.
I had it done before a second story addition. It was by guys who did blown in fiberglass.
I think I paid 5-600 and another 100 for the bags it was blown into.
I followed up with a shop vac. Spotless and worth it.
Just found out from a friend that a local company,Black Hat, does this. You know a PITA job ain't so bad when it's farmed out.
Now I have to find a way to quantify the existing settled Rockwool R-value verses the equivalent R-value of new.
RW=RV 2.25 per inch ?
Edited 2/17/2009 4:48 pm by jagwah
quantify the existing
That's the hard part. As you know and others have mentioned, the air movement means a lot more than the insulation.
Our village inspectors are really stringent on draft blocking. More for fire containment than energy effiency though.
Unless there are extenuating circumstances ... always leave old insulation in place. It won't hurt and it takes a lot to get it out and makes a mess.
I'm finding that out. It will cost approx $1800 to have Black Hat vacume and clean out 1600sqft . While this allows access to a lot of crooks and crannies the pay-back for this is to long.
Unless I can get some real stats that shows a big R-value benefit I'm thinking this isn't as good an idea as I first thought.
Just because something might be logical doesn't mean it's practicle. duh!
That's way high. Ask the guys who will blow in the new if they can remove it.
That would be me. But good point to find an installer and see what if all was done.
Thanks