Here is an as-found view of a new-home attic in Portland, Oregon. Standing atop the usual OSB rim about a hallway ceiling drywall-plunker-access, all is booby-trapped against usefulness. Pulled-up HVAC and fan ducts are in the way, obstructively kinked, everywhere. An adventure has begun, to make the huge attic useful. This post addresses repair of a ten-ft tall bathroom skylight with defective insulation, seen in this view. A full set of captioned photos of the process is consulted.
I imagine a City Of Portland building official inspected and approved the insulation in this home, relying upon 2009 International Energy Conservation Code in effect as the 2014 Oregon Energy Efficiency Specialty Code . See that such code is not accessible despite intentions; there is nothing at followed links. My 2015 IECC book at the Index, Skylights, calls out: R303.1.3 (U-values for glazing), R402.1.2 (skylight U-factor of 0.55, wood frame wall R20), R402.3 (words about fenestration, n/a walls),Table R405.5.2 (1)(standard reference design specifications, for skylights: None.). Defined: R202 (Glass or other transparent or translucent glazing material installed at a slope of less than 60 degrees from horizontal.)
An inspector might have looked for and found R20 at the skylight walls, but I will show that that is only wishful thinking. Find better requirements a Portland, Oregon insulation installer would have been required to follow, under better supervision of Specifications of Energy Trust of Oregon. These say:
skylight—Any window unit in an opening in the roof assembly, including one that is installed at a slope of 15 degrees from vertical or greater.
AT 1.13—Vertical Walls in Attic Spaces
Any vertical wall in an attic that separates conditioned space from unconditioned space shall be sealed for air leaks and shall be insulated to fill the cavity. Insulation shall be secured and covered with a vapor-permeable air barrier. Vertical walls may include side walls of vaults, skylights, transitions in ceiling height or other surfaces. See AT 2.6 for program requirements for knee wall insulation.
AT 2.6:
Knee walls shall be sealed for air leaks and shall be insulated and covered with a vapor-permeable air barrier.
Rebate Rules:
R-15 for 2x4 cavities; R21 for 2x6 cavities; cover attic side with vapor permeable air barrier.
Where this skylight has some 2x6 boards, R21 might be commanded. It isn't clear.
I persist in challenging that attic walls may be as thick as one wishes, unlike exterior walls. Better rules will deal with confusions including so much on-flat framing at a skylight. Where attic walls are extremely challenged by Summer heat, they should be insulated much better than exterior walls. I insulate attic walls to modest R25 (with R30 batts 7.5" thickness and with lessened framing thermal shorts). The vapor-permeable air barrier specified, can't be simpler than a thorough covering of good 3/8" plywood. I offer well-practiced means of attaching the plywood covering.
R21 was not achieved here.
Here is my math for the skylight with insulation merely draped over on-flat 2x4s of the trusses:
Say total inside area of skylight drywall is 100 sq ft. Skylight insulation is in contact with drywall only at end walls, 25 sq ft called R21. On side walls insulation has full effect only where draped over on-flat 2x4s, effectively R21 over 11 sq ft. Remaining area, 64 sq ft, has no insulation filling cavities, and at worst has no value.
100/(Reff + 3) = 25/24 + 11/24 + 64/3; Reff = 1.4 for the entire 100 sq ft area.
My insulation math at 95% furnace efficiency and natural gas cost of $2 per therm, says heat cost per year is: $2.4*100*.88/.95*(1/(Reff + 3)).
The penalty with loose draping, or any draping, is large. Draped insulation must not be allowed.
Accepting that draped batts do resist heat convection, allow Reff = 7, for payback math, vs. better insulation to be demanded and to be achieved. I believe that is a sufficiently large number to avoid over-estimate of weatherization savings. As in the title of this post, accuse that better than Reff = 1.4, can not be demonstrated. Energy savings at skylights is relatively easy, and comes with better safety too. An outside air barrier is required and is nicely provided in 3/8” plywood hard covering. 7/16" OSB saves some money, but scrap must be disposed as trash. In some homes the hard covering of a skylight prevents a deadly fall in an attic tumble against shaft drywall. Where one wants a useful attic and may not use a respirator, a nearly-complete covering of insulation is appreciated. Where my allocated cost of the skylight covered insulation is between $300 and $500, and savings are $15 or more, estimate an acceptable less-than-twenty years recovery of cost.
Mostly, be grateful for better summertime comfort, perhaps continuing to avoid the need and cost of air conditioning.
Pull the nice but useless Certainteed R21 kraft-faced batts from the skylight side walls. Build simple wall extensions of 3/8" plywood cuts 7 1/4" wide that efficiently consume 96" panel length, and stitch them to the 1 1/2" truss depth wherever they fit and align with 2x2 nailer positions, that will support hard siding of 3/8" plywood. In the truss rows, add 2x4's to increase depth for added end wall insulation. Ensure that the plywood cuts forming top and side constraints of the side wall insulation, are very nearly air tight.
Use new Certainteed R13 unfaced batts 15"x96", accurately cut, to cover skylight drywall. Stuff through the floor gaps, completing R60 insulation about the skylight below the floor that is up 21.6" from the attic drywall floor. Where the skylight peak is nearly 10 ft tall, be grateful for the elevation boost of the higher attic floor of 5/8" plywood. A stool for added reach is safely used upon a flat and complete attic floor.
The found R21 batts are stripped of their ripped and crumpled kraft facing, and nearly complete the R30 insulation fill, now easily cut to fit.
Use insulation scraps to fill in low spots of the R30 insulation.
The 3/8" plywood side panels were cut to fit, before the insulation was placed. See that R30 insulation is complete and pillows to greater than the 7.5" thickness defined by 2x2 nailers. See thorough already-completed R30 end wall insulation.
See progress cutting the next skylight face plywood. This end of the now-floored attic is a quite nice, brightly-lit wood shop, for now. I love my Milwaukee saw with laser light well suited to my right-handedness. All sawdust and wood scrap will be recycled as bark mulch. Then don't use less-expensive OSB that must be disposed as trash.
Pre-fit the second skylight face, set with screws.
See 2x6 uprights tied into the truss planes at this end of the skylight. With 2x4 nailers now secured to the side walls, I may release end wall plywood facing to trim the 2x6.
Skylight finished now. The brightly-lighted attic is the best place to do brush-on paint coats of the R15 access cover.
Where Energy Trust Of Oregon chooses to do nothing upon notice of this post, I have edited post Labels to include "Voids Under Attic Insulation." Emphasize then that voids behind some insulation are more sure of being energy hogs, than voids under insulation. The energy dissipation is in convection, air flow past an energetic surface, at temperature different from ambient. Smooth skylight drywall is a superior energy convector of air in motion through gaps. Gaps are made worse where out-of-contact insulation has smooth or deformed facing. The situation is surely better than worst case R2 average, but may not be better than R7. There is no basis for treating insulation as fully effective. There clearly is not compliance with Energy Trust Specifications, in loosely-written new-home building code. Energy Trust calls for treatment of a skylght shaft, R15 insulation, same as for 2x4 exterior walls. New-home building code does not mention skylights. Look in the 2015 IECC code table below to see that a new home skylight in Zone 4 should have insulation of 2x6 construction. In fact, non-specific instructions, are ignored.
Where loose-fill insulation floods an attic floor, a worker is unable to fix lee voids under/ behind crossing lumber, wires and ducts. Most are unable or unwilling to be generous in any compensating general coverage. We must consider the consequences.
I believe loose-fill fiberglass insulation intended R19, is commonly R10 on average. Do the math.
Assumptions:
R2.2 per inch fiberglass. Target depth 9”.
R19 peak over 20%. R15 average except at voids. R2 over voids that cover some unknown fraction, F.
1/(R avg + 3) = F/5 + .2/22 + (.8-F)/18
I believe loose-fill fiberglass insulation intended R38, is commonly R15 on average. Do the math.
Assumptions:
R2.2 per inch fiberglass. Target depth 18”.
R38 peak over 20%. R30 average except at voids. R2 over voids that cover some unknown fraction, F.
1/(R avg + 3) = F/5 + .2/41 + (.8-F)/33
Here is one photo of the found "R19" insulation that inspires this post.
Here is a review of some of my actions that challenge policy in Portland, Oregon, whereby this attic is judged just fine. Leave it as is. In truth, few attics contain greater opportunities for saving with weatherization measures. Even including the cost of a wonderful attic ladder and surrounding decks, all cost of weatherizing this 1988 attic to higher standards of 2014, will be repaid in about ten years.
Details of the storage provision are in a Picasa web album
Truss Attic, February, 2014 .
All details, including construction of R30 insulation on attic walls, are in a pdf album at Google Docs: Truss Attic February 2014 . Please know always to view pdf albums as downloads.
There is real value in 280 sf of added storage space, brightly lit, safely accessible. The inviting access is important, too, in doing the profitable weatherization.
I do all cutting in the attic, catching debris in a sheet which I shake frequently into a 55 gallon drum liner.
Here observe all stages of insulating attic walls to R30, with crossed R15 unfaced batts. The outer covering is 3/8" OSB.
Enabled LED lighting is a big boost to happiness and quality of life.
A "weatherization" contractor only interested in more blow and go void-ruined insulation, throws barriers that may be insurmountable, against best savings possibilities and quality of life improvement.
A weatherization sponsor who teaches and rewards dumb work even that including fraud, devalues good work. Here I criticize the weatherization funds-squanderor I know, Energy Trust Of Oregon . Energy Trust, at article 2.1 in its Specifications , is oblivious of voids concerns. Energy Trust knows better, but further and more disastrously, does not require any "attic floor sealing" before adding more insulation. They go further, declaring that sealing costs are not repaid with energy savings. Not worth the trouble! How stupid! How evil! It doesn't pay, they say, yet they still reward only the contractors who lie about value of blower door testing. Insulation voids and attic floor pits are never found with a blower door. Lee voids are created, always, by the blow and go practitioners of Clean Energy Works Oregon.
Google this topic: "voids under attic insulation" . My work is readily found.
Home Performance practitioners resist the concept of attic floor weatherization measures that are not measurable in a blower door test. That is, just about every measure other than wishful smothering in a disaster of blown cellulose. Pick Label: Attic Floor Pits, for several posts on this subject.
A stairwell is a common example, concealment failed. Simply a large growth of the attic floor, subject to attic conditions, not insulated. Covering is difficult, and very worthwhile.
Not an attic wall. Not an attic floor. Not a Thermal Bypass. What is that, a patch of missing insulation? This is a pit.
This Attic Floor Pit was found and fixed in August 2010.
Closed up with thought. A set of steps up the floor/ stairwell ceiling. A manhole for closure, giving future access for wiring down to an important wall of the kitchen. Photo records given to the customer and saved by me indefinitely, to answer future questions.
Shouldn't all important contractor records, now digital files, be securely archived?
Here is a story of this pit as a Google Docs PDF.
Pit all gone. Safe walking is allowed on a deck. R38 everywhere.
This repair could not have been done through the found access in a closet ceiling. All the work, hauling large objects, was permitted via a wonderful new attic ladder. I think those who fail to provide access, generally fail to do the most important work in weatherization. They will often boobytrap against inspection.
At November 2016, add photos of my first-discovered attic floor pit, understood but not yet named.
Look for unmarked danger between two ABS vent pipes and a steel HVAC return at center of this found-conditions photo. It is a typically darki and dangerous attic under R10 weighted-average. Fixing an attic floor pit is the most-golden opportunity.
The pit is hidden-only, by draped batts, concealed further by general cellulose covering. Could a home owner be sued for maiming an honest, struggling workman stepping-through?
Here is the fully-revealed pit over a basement stairwell with bump-in of a bathroom cabinet, nothing insulated against attic cold and hot temperature.
Safest covering is with 3/4" plywood upon 2x4 bridges. Did I seal it air tight just a year into my learning curve as a weatherization contractor able to learn only by my own intelligence and experience? Maybe not.
The efficient plywood covering was an option only because of a new attic ladder. Recognize the now-safely hidden pit at the duct cluster mid-photo. The plywood covering is buried too by my added 2x6 access flooring.
I will always do what it takes to not bury savings opportunities, or hazards, under insulation in attics. Every job needs at least minimal walkways, to guard against step-through where safe footing becomes hidden. Any footing, buried or not, must be screwed down, as trick footing is far more dangerous than none. Access will happen in every attic, and that must not trash insulation. Accessibility for inspection must be required. There must be no open floor pits, or insulation voids, as complained of in the previous posts, and comprising missed savings opportunities. Every hidden diligence measure with significant cost and savings must be recorded with photographic proof, sparing inspectors of dangerous or impossible tasks.
Why not cheat, when there is low probability of inspection, or a declared policy of permission, that things like "air sealing" are not required. and there are no rules against voids. Voids predictably occur with blown insulation, under or in the lee of lumber and ducts. Voids occur where batts are ill-fit, or are carelessly placed over joist bays that are not full of insulation.
While cheating is permitted, many contractors will feel compelled to participate, for survival. They will offer the excuse that no one has taught them, or commanded them, to do right. One listed on the New York Stock Exchange will do it, perhaps leading the way, on behalf of detached investors. Much of the easiest energy savings in homes will be left undone, for many more years to come. We should not blame only the compromising or dishonest contractors for this. Agencies that will not use their heft for best results, will be largely to blame.
Complaint of a dissing of diligence, in the prior post , had a specific basis.
A large and honored competitor, seemingly gets away with complete disregard of diligence, and outright fraud.
All found trash, and anything they drop, is left for burial. Unfilled joists are left as voids, cancelling the value of covering insulation over at least 25% of the space. Since insulation matters mainly where there was none, added insulation (that I had to pile elsewhere) was almost entirely wasted.
The fraud was in having a contract to seal the floor pits (wiring holes and any open chases), not doing that work or faking it, and accepting payment.
This is a first look at the meanest failure to seal, at the main plumbing vent. This kind of situation exists in most attics, and will be well-known to the worker. A glob in a spot is of no use. The worker is apparently instructed that sealing is expenditure of one can of an inappropriate foam. When it is empty, you're done.
The scheduler, and management, knew I would overturn their work to install an attic ladder, new bath fan, decking and more, out of sequence, after they were done. Despite this, workers wasted foam all over the dirty insulation around the fan, accomplishing nothing.
I got to see work not prettied by exceptional effort.
Spaghetti noodles decorated electrical junction boxes buried under insulation, and about 10% of the wiring penetrations over walls, expending the rest of the can.
The dry spaghetti didn't wet or seal, anything. The worker did not supply that can, or choose what to do with it. This must happen in every home "served" by this competitor. How will contractors learn there is a better way, with my flexible grout? Custom Fusion Pro Tile Grout is a stably-stored ready-to-use equivalent to my flexible grout. Less-expensive grout will work too. Want these for assured full penetration sealing, with easy water cleanup. Avoid chemical foams likely to be tracked onto home floors.
Here is the full extent of the opening at the important pit, going down three floors, and exposing 100 sq ft of interior walls to attic temperature. The waste of savings would have exceeded all savings from properly placed floor insulation. for years to come.
Here is proper closure of the plumbing chase. Looking back in October, 2012 review, I wish I had used flexible grout here, too. Foam can't be relied upon to fill and seal, where it quickly skins over, and, yet sticky, can't be forced-in by fussing afterward.
Here is proper sealing of floor penetrations for wiring, with stuffed insulation, and flexible grout.
All of this has been directly brought to the attention of the responsible rebates sponsor, Energy Trust of Oregon. Upon investigation, without reply to me, the contractor, Gale Contractor Services, got a boost in its rating from next-highest, to highest. What am I to do now, with my proof of their dishonesty?
