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Leafblower/shop vac to move blown-in insulation for air sealing

Ryan Lenz | Posted in Green Building Techniques on

Like most houses, my attic floor is poorly air sealed.  The builder/homeowners of years past have tried to compensate for this with lots of blown-in insulation.  I’m considering air sealing and adding more blown-in (either fiberglass or cellulose). 

The problem, of course, is the existing blown in stuff which is everywhere.  I’d really like to avoid removing it all, as theres probably hundreds of dollars of insulation that is “fine” (i.e. some of it is compressed, and plenty of debris — but its there).  The blown-in is a mixture of the original dark brown/gray stuff (I believe that is rockwool?) and more modern white fiberglass

I’m considering working in a zone-by-zone fashion, using either a mulching leaf-blower or a shop vac, sucking one area of attic floor clean and dumping the insulation into another part of the attic.  Air seal the newly-exposed area (as well as doing some other repairs– mainly installing/fixing soffit baffles), then use the same technique to move the insulation back over this area. 

I’ve seen videos of people using dust collectors to fully remove the insulation (i.e. through 30+ feet of hose into a dumpster), but I wouldn’t think I’d need that much horsepower if I’m just moving the insulation several feet over.  

I could just manually move it using a rake/my hands, but that sounds pretty awful and this technique would have the added benefit of “re-fluffing” the insulation, which it could sorely use. Plus, the should be relatively clean/dust-free, so spray foam/caulk should adhere better. 

Any thoughts?  I’m sure I am in for a really miserable job, but I’m already imagining the satisfaction factor! 🙂

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Replies

  1. Tim R | | #1

    Do it by hand- Just enjoy the terrible working conditions - be glad you don't do this for a living.

  2. Jonathan Blaney | | #2

    I had blown-in removed from a attic I was renovating. They used an electric leaf vacuum with a hose attached to the discharge side. They use it for final clean up. The bulk was removed with trash bags and dust pans. I think the problem is where do you put the stuff you move out of the way so it does not have to be scooped it up twice.

  3. KurtGranroth | | #3

    I've done exactly that in the past! I used a Tora blower / vac in vacuum mode to strip loose insulation from one segment of my attic in order to dump it in another.

    I will never do that again.

    The problem is one of scale. There was FAR more cubic feet of insulation than I had imagined, even in a very small part of the attic. The leaf vac bag would fill up extremely quickly and with only a barely visible dent in the insulation level. This meant trip after trip after trip. Super tedious work! I tried to get more bang for my buck by attaching a very large trash bag (90 gallon or so) to the vac instead of the leaf bag. That didn't really work since the vac requires that the bag be porous to air and the trash bag mostly certainly wasn't.

    I had notably better luck just using an aluminum wide shovel to just shovel the insulation into the large bags. That only sent so far, though. I couldn't really do it where there were any wires. Still, that plus the leaf vac combined did the job.

    When time comes to do it again, I will either get a much more robust vacuum (like one of those dust collectors) or I'll just tamp down my "never throw anything out" impulses and hire a team to remove it!

  4. Ryan Lenz | | #4

    I think a key distinction here is that I am not actually removing the existing insulation from the attic space. I am just moving it to give me access to the top plates, wire penetrations, etc. then moving it back. I understand the hauling bag after bag would be incredibly tedious.

    I think what I might need to do is place some plywood 'landing pads' in the general area of the exhaust from the blower/dust-collector/vacuum, that would help to support the insulation. I'm a bit concerned about the weight of a mountain of insulation.

  5. T Carlson | | #5

    Ive done air sealing retrofits on hundreds of houses with a crew. Obviously wanted efficiency so early on I thought a leaf vac would give me an efficiency edge. It will not, extremely dusty.
    Big plastic dustpan is what we use and wing it to the side for wall plates. Fans and light boxes we clear by hand, only takes a second and doesnt have to be completely clean. We kick it back a little bit and when Im installing I can use my insulation machine to flatten the existing when we are blowing cellulose over the top.
    Also tried a plastic shovel, abandoned that idea as well.

    1. Ryan Lenz | | #6

      Super useful to know. Thank you. I suppose sometimes you can spend more time trying to save time than just buckle down and do it. I tried a bit with a crappy dustpan today and I think you might be right. I think I'll go dustpan shopping and see if I can find an extra wide (23" would be awesome!) one to fit right between the trusses.

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