learned a couple of things......cellulose

[Rosco]

Just had my bonus room apartment insulated with blown cellulose. I watched the guys from start to finish........here is what I learned;

Very dusty operation. Wish I would have taped off, covered everything in the garage.

Seal all of your electrical, cable, light boxes well with caulk or foam and tape the front with duct tape.

I think I have found part of the issue where cellulose gets a bad rap for settling. While watching the guy "shave" the cellulose after being blown into the wall I noticed the brush was shaving about 1/16th of an inch into the wall cavity (checked it using a straight edge). I pointed it out and they kinda thought it was funny. Now measure that 1/16th by the entire cavity, then the entire wall............

He resprayed that section and then only applied very light pressure to the brush. Left some portions of the cellulose actually sticking out about 1/16th of an inch, which can be easily compressed with sheetrock.

Call me crazy, but that 1/8th inch (total) difference on the entire wall surface adds up to a lot of insulation. I feel that the minute gap would have led to settling after a while, not to mention the air gap against the drywall.

They said that they have never noticed it or been asked about it before.

The next area I noticed was the upper corner wall cavity at the top sill plate was not getting blown in completely on some of the cavities. Depending on how tall the sprayer is and if they are using a scaffle makes a big difference. Visibilty becomes limited while blowing. After I pointed it out they used a small scaffle and ensured complete packing by using different angles.

They were great guys and put up with my ****. I hope this will help anyone who is going to get this done.

Bottom line, this is a messy/dusty process. If you do not completely seal all electrical and lighting fixtures in a house I can see where years of dust will be a problem.

 

[scuba0459]

Thank you. I am planning on having this done as well

 

[Busted_Knuckles]

There was another thread that approached this subject on the blown cellulose recently, IIRC, the O/P was talking about dust being a problem post construction, in each room that had a ventilation fan. I think was he was getting at, was that when the fan was on, some air pressure (negative) was pulled from the openings in the room (wall switch, receptacles, floor seam), which pulled minute quantities of dust into the room over time, anyhow he reported that he had a permanent dust problem, and wasn't happy with his choice of insulation. He also noted that a friend had built a similar house, same area, same builder, and went with blown glass, and he had no dust, as anecdotal evidence.

 

[Teken]

Great info much thanks for the feed-back . . .

 

[trythis]

I had this done, I didnt pay so much attention to the 1/16th, but I think it was pretty flat, and even with studs. 2 years later I have opened one of the walls, and the stuff is glued to every surface. It is very tight, quite hard to compress and I just cant see it settling. I think the settling comes from the loose fill technique that is done after the drywall or plaster is in and not using the wet blown in method.
It can be torn for electrical wiring but refilling with loose seems silly, I think I will patch fill with fiberglass, even though I HATE fiberglass. The cellulose guys that did mine would occasionally fill in an odd spot with FG too, so it does have its place. My ceiling is packed with it, but I dont have negative pressure pulling it out. No dust.

 

[jklingel]

Sounds like you had wet spray, which has an adhesive so it stays put, as noted above. Regardless of insulation type, seal, seal, seal. Anything you don't seal from the insulation is letting air into the insulation, carrying moisture and btu's.

 

[rwhite692]

Call me crazy, but that 1/8th inch (total) difference on the entire wall surface adds up to a lot of insulation.

Okay, "you're crazy"

 

[timgr]

Easy arithmetic problem. In an 8' bay, 16" center, 96" * 14.5" * 0.125" = 174 in^3. If the cavity is 3.5" deep, that's a volume 3.5" deep by 14.5" wide by 3.4" tall. So you could expect settling of about 3.5" with that amount of gap. Not crazy ... significant.

 

[trythis]

If it is blown in wet, it glues together, it will not settle.