Thursday, April 10, 2008

Distributing or Hauling-Out Loose-Fill Insulation

55-gallon drum liners are useful for transporting debris and loose-fill insulation in an attic. They may be collapsed as needed to pass through an opening, yet are self-supporting at a thickness of thirty mils.

There are many uses including painting or plaster prep, where major debris is collected on a sheet, and the loaded sheet is easily shaken out in the drum liner.

I buy them from:
CDF, Inc.
77 Industrial Park Rd.
Plymouth, MA 02360

They are 30 mil thickness, Product Code 5530/34.25-G4.
I made a first purchase as a case of ten, with cost and weight breakdown thus:
Containers weighing 39.3 lb, plus box, 45 lb gross.
Charged $118.70 plus $92.91 FedEx freight, $211.61 total.

Shopping Update at 7/14/2023
For delivery in Western United States, I am referred by CDF to chemicals distributor Terra Firma, of Los Angeles. 55 gallon drum liners are manufactured first for clean shipment of chemicals in 55 gallon steel drums, and Terra Firma generously sells them to permit CDF product sales with reduced shipping cost. Here is their offer to me:

CDF 55 Gal straight side 30 mil drum insert – 10 inserts per case – FOB Carson, CA

Our item # CDF552
Minimum order quantity – 1 case
1 case - $29.11/insert
2-3 cases - $26.62/insert
4 cases or more - $24.33/insert
Lead time:  3-4 days once we have your account set up, assuming we have stock available.

See cost $291.10 plus shipping in excess of $100.
Up from  $118.70 plus shipping, in 2008. That's rise of 16% per year, for fifteen years.

I will learn what is least-cost shipping with Terra Firma, probably LTL freight.

Seeking least-cost purchase, persist with direct purchase from CDF in Massachusetts. 
Unit cost is $20.6223, $206.22 for ten.
"Shipping UPS is $428.62 for 1 box. LTL rate for one box and it would run approximately $250.00."
About $456 then, direct from CDF, for a box of ten.

Here is my full CDF purchases history:

In summary and with the present opportunity, here is the drum liner cost history:

With a purchase, think to buy the dust covers at no added shipping cost.

Cleaning Up A Blown-Cellulose Attic

This attic floor of 2x6 joists on 16" centers had found insulation of a relatively pleasant form of cellulose, up to the tops of joists, R18. The cellulose is compacted to give space for kraft-faced R11 batts. Unfaced R19 batts cross joists to complete an upgrade to about R45. A vapor barrier is acceptable anywhere it will remain securely at temperature above the dew point. It is nice to not place unfaced fiberglass against the cellulose, where picked-up batts would again raise cellulose to the surface.

(Edited at 11/13/2009) The claim of R45 is high. I will call the compressed cellulose R13. Applying my Insulation Math, consider parallel paths for the thickness of 2x6 floor joists.

1/Reff = (1.5/16)/ Rjoists + (14.5/16)/ Rinsulation
where Rjoists is taken as 0.94 per inch (douglas fir), 2.4 for 2x3, 3.3 for 2x4, 5.2 for 2x6, 6.8 for 2x8.
1/Reff = (1.5/16)/ 5.2 + (14.5/16)/ 24. Reff = 18.
Adding R19 batts, total insulation value above the ceiling is R37.

This added exercise tests my installation against a two-thirds rule commonly applied, where less than one third of the total insulation blanket is allowed to the warm side of a vapor retarder. Credit R29 above the kraft facing, R8 below. 29/37 = 0.78. The installation passes the test, but that is not an appropriate end of the thinking.
From a Google search, subject: "vapor barrier two thirds rule"
I have done right for the climate of Portland, Oregon. From study of dew point data for Portland, I have justified a one-half rule. In fact I have never departed from a two thirds rule.

Lacing Insulation to an Attic Hatch Cover

An attic hatch cover of wood or drywall should be insulated in a lightweight frame, not simply by stapling on some twine. The reliefs in this frame permit lacing, and offer finger holds for lifting. Insulation here is high-density R15, in three layers, the bottom having a full-area vapor barrier. A single high-density R38 batt would also do the job.

Duct Wrapping

Here are photos of the application of a duct wrapping material produced by Johns Manville. The material is labeled "Basement Wall Insulation." It has a rating of R11, and is sold as a bulky roll 48 inches by 200 ft. It has a tough white polyethylene and skrim facing. It is best attached with a corresponding white polyethylene and skrim tape in 3 inch width. I expect that corresponding wraps and tapes with foil and skrim facing, similarly pliant, will be associated more with a HVAC unit and its immediate ducting.

The first picture is of a 16" diameter steel ventilation duct. The duct itself has seams and joints sealed with foil tape.

The second picture is of a cabinet set in a home kneewall. The tape of course sticks securely to duct wrap and to itself. It also seems to bond securely to clean wood.