Blown-In Cellulose Insulation


We have just completed our first experience with blown-in insulation and have learned a couple things we wanted to share.   

This is one of those oh-so-rare moments when we aren't pretending to know a lot about the subject; we just felt we'd learned enough the hard way and that perhaps you wouldn't have to.



First off, based on our research we expected insulating 600 square feet of stuff space would take a few hours.  It actually took a couple days.  

One obvious issue is that this task is intended to be addressed by to or more people.  I would guess a second person would have cut more than half the time off, whereas most tasks take one person less than half the time it would take two.  

Ideally, one person would be in the attic blowing-in, as it were, while the other would continually load the hopper, and switch it on and off as necessary.  When only person is on  the job he or she must load the hopper, turn on the machine, open the gate, run up the ladder, locate and take control of the already-blowing hose, apply the insulation, rehang the hose, return down the ladder, and reload the hopper.    

The process gets trickier when the hopper is rooms away from the ladder or when the hatch is tricky to crawl through.

The time issue was compounded by the fact that, once we had everything in place we started discovering errors, oversights, and omissions that  needed repair.  Having already picked up the blower we were on the clock, so it would have been better to have sorted out all the issues ahead of time.



We used twice the bales of insulation than we had planned on.  We are very happy with the results and have no complaints about the amount we used but it would have been awkward if we had not had the excess on hand.  

We've reviewed the math and we should, theoretically, have used about 18 30-pound bales to lay a 12 inch layer of cellulose insulation over the r-30 Roxul.  We actually used 30.  Part of the overage is that the endstate is not perfectly flat and level so we rounded up to ensure that every inch was 12 inches or deeper.  We've frankly no idea where the rest of it went.



As we researched cellulose insulation we were happy with GreenFiber Low Dust Cellulose, which is available in 19-pound bales at HD and Lowe's (no particular endorsement here but their websites make it easier to research a product and know what's available).  The Depot has the same product in 30-pound bales, sold by the 36-bale pallet.  The price of 36 19-pound bales is almost exactly the same as 36 30-pound bales, so it makes more sense to buy the pallet.

We thought we would have leftovers enough to do Jean's old house, and maybe our own as well.  No such luck, but that's how we happened to have enough to finish the job in the Little Easy.

If you are planning to blow in cellulose we recommend you significantly round up.  It give us a ring and we'll get it wrong for you.



As above, we used a low dust cellulose product.  This turns out to be a flagrant lie.  The amount of fine airborne dust entering the house through a couple of small hatches in the ceiling was enough to smother a horse.  Everything throughout the Little Easy was coated in a layer of pale grey dust.  Any time we took off our respirators we were coughing and sneezing to beat the band.

The dust issue is not really a problem in new construction but would present serious challenges in a furnished, occupied residence.  Caveat insulator.  Dampened sheets fully blocking every doorway would be a start but expect to spend a day cleaning when you are done.

There's also a fair bit of wastage on the floor.  When you open each bag a small amount of cellulose falls on the floor.  Each time you pull pieces off the bale to throw in the hopper pieces fall on the floor.  Frequently pieces bounce out of the hopper onto the floor.  More crumbs fall out of the empty bag as you scoop it up to throw it out.

Additionally, blown cellulose will fall out of your hatch/es.  There's no real way to avoid it.

We ended up with a deep-pile shag carpet's worth of squashed cellulose on the floor in two rooms and a hallway.  No problem in new construction but aggressive tarpage would be recommended in an occupied house

if You're Doing It Alone


Something we found expedient was to hang the blower hose nozzle and let the insulation pile up.  We scattered a few screws into the collar ties over each of the hatches into the attic.  We wrapped the nozzle with a short bungee cord enabling us to hang the hose at an attitude and angle of our choosing.  

We loaded the hopper with a half-bale, switched the machine on, opened the gate, and let her run.  Rather than hustling up into the attic we would stay below and feed the remainder of the bale into the hopper and let it all now through.  With the hopper empty and the machine ditched back off we'd head up into the attic.  There we'd find a large pile of insulation which we could easily push to where it was needed.

For pushing we put a small broom-head on a painter's extensible pole (Purdy Long Arm).  It was easier than it had a right to be.  We used the extension pole later to sweep through the top layer of insulation to leave a more even, level surface.  Try it: it's way easier than it sounds, and when you're alone this is by far the faster and easier alternative.

Another handy TTP was indirect application.  When blowing into a corner the force of the wind blows the insulation right back out of the corner.  Bank your flow off a wall or ceiling to enable the insulation to fill the former in.

Likewise, when filling around the chute extending up from the final hatch place your hand into the flow to stop the wind from blowing the insulation away from the chute.

Comfort and Safety


Disposable dust masks are not up to this task.  A half-face respirator with any particulate filters will do much better.  Safety glasses are also not enough.  Goggles or perhaps a full-face respirator would be a better idea.  DeWalt (imagine that) makes a decent set of goggles (DPG82-11) but there are, doubtless, others available.  

It should be noted that the old standard safety goggles with perforations all through the sides will be worse than not wearing glasses at all.

It should also be noted that the ad copy promising an itch-free experience appear to be correct, at least in our experience.  



Skye, the lady at Home Depot's Pro Services who rented us the machine rocks.