Monday, December 7, 2009

An End of Rebates, A New Job for Rebate Organizations

If we secure the needed investment funding in Oregon, weatherization retrofits will become just a matter of conscience and cause, with all qualifying projects funded interest-free. A flood of work will be released. Organizations employing power through handout of rebates, will be reinvented. They will find plenty of work in supervising the qualification of projects, and supervising the just conduct of the large amount of work yet to be done, to stop being a wasteful nation.

I don't think homeowners not on the edge, ever needed rebates as cause for action. It was just a matter of fairness. To not miss out on money a more clever or careful person might find. Kind of like the bargaining for low air fare. We never minded contributing to survival of our needed carrier. We just didn't want to pay more than someone else.

Now, some who have drawn rebate money as a permanent drain of the Public Purpose Fund, might wish to reinvest their energy savings to help others. That 3% tax on utility bills should accumulate hereafter, being let out only on interest-free loan. If the fund is a growing pool, it will not be seen as available for other government needs.

Friday, December 4, 2009

Clean Energy Works Portland

Oregon has a very promising young politician, State Representative Jules Kopel-Bailey, serving Inner Southeast Portland neighborhoods. Through his leadership, Oregon has a new initiative for enabling weatherization in homes, enacted as the Clean Energy Fund. Listen to a Podcast here, where goals are simply expressed, in an interview conducted by Jesse Jenkins, of The Energy Collective.

Here is the enacting legislation , HB 2626 of the 2009 Oregon legislative session.

And, here is a longer "C-Engrossed" version.

Progress in this plan is at a snail pace. Here is a small public enactment within City of Portland, as Clean Energy Works. A pilot program has expired. There is nothing to apply for. Where is the commitment to action? There was one publicity posting of a pilot project in The Oregonian, as presented online here. Newer OregonLive posts brag of the pilot program.

The City of Portland is directing action at benefiting contractors, with delegation through Energy Trust of Oregon, to empower largest contractors or to low-skill general contractors who employ home performance testers, and subcontract work for profit. Everything should empower the people in need, to simply qualify projects, and do work themselves, or choose their own contractors. The big-guy testing is rarely useful in qualifying work, and is contrary to service where a conflict of interest is established. All testing should be impartial, by other organizations.

The public deserves stronger action now. This isn't about jobs. It is about getting investments done, with rapid payback in energy conservation. I think there is a special need to motivate and enable owners of rental property, where tenants suffer for lack of insulation or a crummy old furnace. Let the no-interest enabling money go to contractors and materials suppliers on behalf of, and in the service, of tenants. In an owner-occupied home, savings from lowered utility costs repay the loan. An owner of rental property will find means to pay off a ten-year loan. Up-front money is harder, and the tenants, and The Earth, suffer.

I am proud of the former Oregon State Representative for my neighborhood, now US Senator, Jeff Merkley, who offers the up-front weatherization financing nationwide, in Bill S. 1574. Oregon proudly followed British Columbia, with our Bottle Bill. This action is far more important. It WILL empower work more effectively than after-expense incentive payments. Please see more about association with HB2626, here.

I want to be part of debates in Oregon where the legislation is acted-upon, as required, by Oregon's Department of Energy, for ALL residents.

Saturday, November 14, 2009

Fire Safety and Insulation

Talk of vapor retarders, linked to fire safety issues, should be followed by more independent thought on the fire safety issues. Everything in life is compromise against competing concerns. I'm proud to present a clean, physically-safe attic. Yet, I can not offer a maximum in fire safety. I'm stuck with lots of pre-existing features not open for discussion or change. Residential codes allow a bias in favor of usability and resale value, and I think that is where I am aligned. I put in clean, serviceable batt insulation, when starting with none. I don't mind a bed of rock wool or cellulose to start, leaving in-place with contribution to better fire safety, in addition to avoiding land-fill even for some dirty stuff. Cover the dusty stuff, I will, and in an attic floor, I doubt covering batts degrade fire safety.

I have taken the step of burning samples of Tenoarm and old, reject batt kraft facing, in my garage. Both do burn. The tarred kraft facing with some ready fury. The Tenoarm, not contained, sustains flame, but progressively falls out of the flame in drops of melt. I don't know how to proceed further, and leave advising to some Federal consumer-protective force.

Through a customer, I am awakened to concern for fire safety in the insulation of sloped ceilings, that connect knee wall closets with an upper attic. Such passages are found with various draft-stop provisions, more often wide open than draft-stopped. When wide open they tempt provision to moderate roof temperature, by baffling over new insulation. If roof joists are 2x4, I argue that R15 batts, pressed-down, leave sufficient breathing space, and that works even if the bottoms of the slope cavities are draft-stopped. I recently completed a new-drywall insulation placement with 2x6 roof joists, where breathing spaces were forced by DuroVent plastic baffles. Upon prompt by drywall contractors, I must reduce the applied insulation from R21, to R15. I may instead argue that the spaces should be draft-blocked, removing the baffles.

I wish a blog or some other internet forum might moderate discussion toward appropriate compromises.

Thursday, November 12, 2009

Vapor Retarder Two-Thirds Rule

When placing insulation in Portland, Oregon, I rarely use material with a bonded-on vapor retarder (kraft face). I am aware of propaganda favoring cellulose, and raising fear of fiberglass batts, in The Big Burn Video. Proponents of cellulose have dealt with criticism of organic cellulose as inherently less safe than inorganic mineral insulation, and tilt the table too far in the other direction. The video presents ideal cellulose, and fiberglass with no description. I imagine the fiberglass was a least-favorable setting, with air channels (chimney path) the length of flammable kraft facing. A fair comparison would have fiberglass totally filling joist bays, with no kraft facing.

I will never use kraft facing in a wall or in a new-construction ceiling. There I use complete, taped sheathing with polyethylene sheeting designed for the purpose, Swedish Tenoarm. Aside from fire safety concern, I save time and get better fit, in custom-cutting unfaced batts. I also follow the advice of the USA importer of Tenoarm:

I will use kraft batts in an attic floor, to isolate new material from found loose-fill insulation. I use original reasoning in study of dew point data for my location, as reviewed in this posting, with a current update. The commonly-understood two-thirds rule states that a vapor retarder should be to the warm side of two thirds of the applied insulation.

Thursday, October 29, 2009

Beginning Thoughts of Math, Carbon Footprint

In effort to show the value of home energy conservation efforts, I have done math for heat transfer, and fuel costs crunched for my city. Now, I want to join the game of declaring benefits as reduction of carbon footprint. An advantage in this is that low, subsidized, cost of heating fuel is divided out. I accept numbers from a recent issue of National Geographic, March 2009, p 67:

Driving: a gallon of gasoline adds 19.6 lb CO2.
One KWh electric use adds 1.5 lb CO2.
100 cf of natural gas emits 12 lb CO2.

I need to back up a few steps, and understand where I am expected to go, with reduction employing such numbers. Start with the EPA Household Emissions Calculator.
Here is my annual carbon footprint, living alone, working hard as a weatherization contractor:
12,438 pounds CO2 in driving 13,400 miles per year.
2,808 pounds CO2 for 239 therms of natural gas in an efficient furnace heating my modest 1000 sf home and productive workplace.
7,063 pounds of CO2 to generate 7663 KWH of electricity per year.
22,309 pounds CO2 before savings efforts volunteered, about 1000 pounds of CO2, through car maintenance and through steadfast recycling.

Numbers correspond fairly well with the National Geographic conversions. I am near the 20,750 per-person US average. I have begun to share my home, and that will push me below the average. The sharing of my home is in fact the most powerful thing I can do.

Better-educated by this study, I am inspired to save a few thousand pounds of CO2 emissions per year. Here are several ways I could save 1000 pounds: Drive less by 8%, fifty gallons, or 1080 miles. Reduce electricity use by 14%. Reduce my use of natural gas for heating, by a harder-to-do 35%, or 85 therms. There is promise in all of these. Only heating reduction through conservation, what I do for others as a contractor, is painless.

I began this writing exercise upon concluding that large effort in a customer's attic of 720 sf, going from R13 to R40, would save fifty therms, the equivalent of using thirty gallons in driving, and about 600 pounds of CO2 averted. It was a small gain, but beyond painless. It is a more than twenty percent annual return on the customer's investment, forever, and further value in more-comfortable living. The customer will still look for harder ways to reduce footprint. The saving corresponds also to that of diligent use of clothes lines in a wet climate; this with no effort.

Monday, October 12, 2009

Free Access to Codes

In a previous post, I expressed my wish that all public regulations important to my safe workmanship, should be available for free online access. I am pleased to find that the National Electric Code, maintained by NFPA, the National Fire Protection Association, can be read online. You only need to register for access. There is no cost. I wish it were word-searchable and printable. If it were pdf, I could readily enlarge for less challenge in reading.

Now, how about building codes?

Saturday, September 5, 2009

Sealing Attic Floor Pits

Dropped ceilings in closets are seen in an attic, as floor pits. Photos here, with corrective action, are of a home built in 1953. Attic air is freely admitted to walls the full height of rooms below, amplifying the ceiling-area heat loss or gain, by an order of magnitude. Let's try the math here, on that order of magnitude. Numbers in play are represented by L and W, the dimensions of the ceiling, and H, the below room height. I see that the influence of closet interior walls is debateable where the door is normally closed. Figure the amplified area as 2* (L + W) *H, where L = 46, W = 31 and H = 96. 2* (L + W) *H = 103 sq ft. LW = 9.9 sq ft. The amplification factor is 10.4. If insulating 9.9 sq ft saves $7/ yr, the larger saving is $73/ yr.

Carry the argument of an order-of magnitude multiplier a bit further. For this closet, if the door were left open, the area exposed to attic-room temperature difference increases by the interior side-wall area below the drop. The larger amplification factor is 13.5. The smaller amplification factor, (2* (L + W) *H) / LW, is a minimum for home situations. I imagine home situations where the minimum is larger than 10.4. How about a long, deep wall used as a ventilation chase? Ten ft long, a foot deep. The amplification factor for a one-floor 8-ft chase is 17.6. If the chase runs down two floors, 16-ft, the amplification factor is 35.
I argue to my rebates manager, that pit closure is far more important than air sealing opportunities in an attic floor. Pits are often overlooked or are improperly fixed when found. Old insulation may be draped over a pit, merely hiding it, with slight impediment to air flow driven by the temperature gradients. A loose-fill installer will almost never know of the neglect. There are no incentives to pick up that old, dirty insulation to find and fix pits or other problems, in practice. In my area the testing trade, Home Performance, is promoted by a fifty percent of cost rebate for air sealing work if that achieves quite-large drop of infiltration, 300 cfm or more under test conditions. That is absolutely unhelpful here. The problems are not made detectable by blower-door conditions of pull from the attic. A pit doesn't contribute to infiltration.
My closure of the pit employs half-inch drywall pulled up to floor joists, and edge-sealed with spray foam, or better, my flexible grout which I offer for free with easy conditions, as a sample. I prefer GP Densarmor fiberglass-faced drywall, kept as scrap from my closet projects. Screw a length of 2x4 under the drywall for lifting and anchoring. Sandwich the drywall with another 2x4. I shape Densarmor edges with a Shurform plane. Ordinary drywall is too brittle, and paper facing resists trimming of edges.

This relatively simple pit closure took more than an hour of actual performance. With an extra trip it is far more costly to an installer, if not known in advance and rewarded through a contract. If a contract change must be argued or if the worker is somehow detached from responsibility, a proper fix is not mere due diligence. It is unlikely to happen.
This home was like a test lab for pit sealing. A rare opportunity, yet daunting since problems were detected upon bidding. Daunting since more time would be spent in the attic in summertime heat. Daunting since pulling drywall up under floor joists requires more than a bit of cleverness.
There were three more pit areas, one including a dropped ceiling over a bathtub; another a long wall with dead volume associated with a grand fireplace; and another very simple at a dropped ceiling over the home entry. That at the fireplace involved working in extremely cramped overhead, out to an outside wall, and had six hours of actual performance. Multiple visits dealt with rerun of interfering wires. All of these problems were happily hidden, until I pulled up nice-looking insulation.
I challenge Energy Trust of Oregon, and other rebate organizations, to do a better job of serving and protecting Utility consumers. All stuations that invite being overlooked, should be specifically reported by weatherization contractors, to secure diligence rebates. I ask for a new rebate program, where reported pit closure qualifies rebate-times-ten for involved floor area. All diligence rebates should be presented for public examination and learning. This reward approach is consistent with the fact that some pits are large enough that pit walls could be insulated instead of making a difficult but fall-protective cover. The alternative reward of fifty percent of repair cost is of comparable size, and would work if the conflicted tie to reward those invested in Home Performance, were removed. Keeping the tie here is absurd, yet that is the dogged position of Energy Trust of Oregon. Keeping the tie is a grave disservice to homeowners. While I owned a blower door, modestly invested in Home Performance, I NEVER found a problem not more-readily detected by simple observation. I never found a home without a great excess of infiltration, to be dealt with by progressive and obvious measures such as window replacement. Tests taught nothing.

Here is related comment upon feedback to focus on unique and interesting opportunities, and to raise the state of the art in weatherization. At the last Energy Trust Trade Ally meeting I attended, I shouted out that blower door testing for unique purposes should be rewarded directly to the contractor, a token amount of $50, if he offers a report of why and what learned for PUBLIC DISCLOSURE. A family of public reports would raise the state of the art among contractors nationwide, would inform the DIY public, and would sell Home Performance services. We all need to better imagine the situations where blower door and/ or infrared thermography testing profits the homeowner. The situations may be uncommon.

Thursday, August 27, 2009

Using Baffles With Attic Batt Insulation

This use of a one-foot length of Durovent baffle material seemed to work. The flimsy foam shape is held against roof sheathing by batt insulation stuffed beneath. Placing the top-course crossing batts goes faster, and I get more insulation at the periphery, when I don't have to worry about blocking vents, of whatever baffle material is deemed acceptable.

Here is a photo album detailing this job, rationalizing use of flimsy Durovent baffles. I have never used cardboard baffles.

In 2016, advise against use of Durovent, too. I have seen expanded polystyrene board  insulation under siding, disintegrated under heat of less than ten years service. I will not guarantee service of EPS. 
I now use only strong plywood baffles, reaching all the way to the attic floor and blocked by good 2x4 remnants. Please see a presentation at my web site. Here is another blog post, where plywood baffles were foollishly installed. For the photo at the left, note  concern that plywood roof sheathing should have edge clips over 24" spans. Brittle shingle underlayment may be cut by a plywood edge, causing roofing failure (a hard-to-fix leak). How, now, would one align the plywood edges? This is stated in a September, 2012 update of this post, I have become opposed to deployment of continuous roof vents, especially as soffit-area air inlets, which slot the sheathing and underlayment. I want to rely on underlayment as a second stop against water driven under shingles. What will happen in a reroof, where slots are "lost", and a product like SmartVent no longer covers a tear? Make good use of your soffits, if you can.

Add more on 7/26/2016, from this album :
R30 crossing batts align with tops of baffles 18" tall. Make the baffles from taller scraps if you wish. With this steep roof, place outer R30 batts as 12” lengths. Split a 12” R30 batt to stuff under a baffle. Take care to fit most batts of  consistent 24" x 48" dimension, so that lifted batts someday do not become a jigsaw puzzle.

In a national plague of stink bugs, expect frequent need to reach down the tolerant baffles occasionally to vacuum. You could never do that through a cardboard silly-thing 36" tall.

Wednesday, August 5, 2009

Kneewall Closet Access and Insulation

The light at the floor aims at a difficult insulation opportunity, behind finished knee walls.

Let's see what is behind this crude door.

A conscientious installer of cellulose insulation made a best effort to weatherize the ceiling of the home Living Room. Coverage is a spotty twenty percent, with none in the lee of obstructions.

I will fix this, from a new, better access. Attic Access is what I do, and that involves willingness to cut and crawl through plaster walls.

With a hole in the knee wall, the problem is manageable.

I have improved ceiling insulation to R40, over 80 sq ft, and the accessible areas of the cut knee wall to R15. After rebates, despite access cost, the job cost will be repaid by energy savings, in less than ten years. For the homeowner, it is one more thing to feel good about.

The real-plaster patch need not demand support by a professional plasterer. Block opening edges and reset lath. Repair pre-existing cracks with flexible grout as a nice plus of the weatherization. Prime edges, brushing on Plaster-Weld. Screw-attach expanded-metal lath. The patch area is easily filled in one application of Structolite plaster, struck level with a 4-foot feather-edge if it fits. Here, there was compromise, using other tools to level the patch.

Final finish is with broad application of mud. This will need texture and primer.

Sunday, May 24, 2009

Recycling Extruded Polystyrene Foam, (Styrofoam)

This post is edited as of November 7, 2009.

EPS foam blocks (Styrofoam) ARE recyclable, in Portland, Oregon. Recycling, of clean material only, is a service of Pacific Land Clearing, at three of their four locations in metro Portland.

This Bee Newspaper review, tells the story, as of June 4, 2008, with info on what PLC does with the styrofoam. Reported options include a volunteered service of the seasonal Moreland Farmers Market, which brings a weekly collection to PLC.

I find styrofoam stored in attics, often. Stored. Not really doing any good as insulation, where air freely seeps under. I collect material in a 55-gallon drum liner, and when full, make a trip to a PLC location. I want my city to require all recycling centers to accept material, and bring it to PLC. As noted in The Bee, the mindset that styrofoam must go with trash, is hard to undo.

Every city should look for means to consume styrofoam as done by PLC and as described in The Bee.

Friday, May 22, 2009

PTCS Air Sealing? I Sold My Blower Door.

The meaning of the acronym PTCS, is Performance Tested Comfort Systems. This resides at, which is maintained in Portland, Oregon, by Ecos Consulting. PTCS has been a bugaboo to me. Oregon Department of Energy has delegated its training responsibility for weatherization contractors, to ptcsnw/ ECOS. That responsibility currently is carried out by instruction through Energy Trust, in sealing HVAC ducts, and installing heat pumps. These classes are motivated for a large number of weatherization contractors, by Energy Trust of Oregon rebate requirements (see end of this post). Useful skills will be taught in the classes, but they should not qualify anyone and everyone, to work as HVAC specialists. I would not ever compete for that work, but would refer a real specialist that I trust. I don't want to invest in the HVAC instruction, for a couple of reasons:

First, there is substantial cost of about $1000, my time of two full days in class, and a $400 tuition. If the instruction really is important to people I serve, the tuition should be rebated somehow as reward for my unpaid dedication to my community. My costs are in the thousands of dollars, for unrewarded bid visits and telephone advice, often surpassing what a paid auditor offers a homeowner. I think the knowledge of PTCS that should matter to me as I make attics useful, whatever it is, is in the public domain, and should be accessible online. All paid people are ultimately funded by taxes, here a 3% addition to natural gas and electricity bills. Anyone, not just paying contractors, should get back more than one-time rebates for conservation measures. There should be no obstacles between public-domain knowledge, and the public, anyone, who might have use of that knowledge. The gripe is similar to what I feel about codes turned over to publishers, to make a profit. I will pay for nicely-bound code documents, but expect to find them in online pdf form, for free download. There should be no barrier of access, to things in the public domain, that I need to know.

Second, I know that the instructor of Ecos/ ptcsnw duct sealing classes, has stated in a Home Energy Magazine article here, that duct sealing with wrap-and-goop is objectionable to many workers, and that foil-faced double-backed butyl tape I have reported finding useful, is good. 2009 Energy Trust Specifications, at DS 1.5, ban the foil tape except on air handlers. I can not accept that I have done wrong in my employment of Polyken Foilmastic 367-17. I have protested the Energy Trust rule. One application I am absolutely proud of, is the joining of flexible heating ducts to a steel collar insufficiently smaller than the duct ID. I have achieved secure coupling in several homes, where ducts were detached, by slitting the duct in 120 degree sectors, applying 367-17 to the ID tightly-smoothly-generously, to form a bell. I then wrapped the improved duct and collar in OD application of 367-17. I challenge anyone to do this repair with wrap-and-goop. If I am in rebellion, I can not attend the class.

I have not invested in the tools of real HVAC professionals, including a duct blaster and other more-complex equipment. I bought a blower door last August, but just sold it. I only bought the blower door, to support customers with air-sealing-achievement rebates. Thankfully, such rebates have been eliminated in Oregon. I do not wish to compete dishonestly with the real HVAC professionals, or with professionals engaged daily as Home Performance testers. Home Performance testing demands daily practice, and investment in all tools, including all elements of Energy Conservatory products, and infrared thermography equipment. I am sad that my buyer, a general contractor like me, intends to delegate testing work to an employee, also not a dedicated professional, and to snag general contracts through the aura of holistic treatment of a home. General takes cuts on Subs. I don't do that. I want the homeowner to independently choose best contractors for all work. No cuts out of the homeowner's pocket. Home Performance testing is a summary task, after obvious things have been fixed. Get a greenness score for real estate purposes, and be sure a home is not too tight. One need not do testing, to imagine big measures of weatherization, HVAC upgrades, thorough crawl space ground barrier sealing and radon mitigation including heat-recovery ventilation.

There are strong emotions, perhaps mostly relief, in selling the blower door, though it had been sitting idle in my living room, tying up capital. I had been refused an air-sealing rebate in an oil-heated home subject to Oregon Department of Energy rebates, for want of PTCS certification. In the job, I patched visible, large holes, including a car-bashed garage wall, not found through another contractor's blower door test. That was not work for an HVAC professional. I promised to sell the blower door, if ODOE would not deal with this irrationality. Another bump to emotions over blower-door irrationality is in performance testing as a BASIS for duct sealing. (The PT in PTCS, taken to excess.) Energy Trust allows a rebate for duct wrapping, only if the ducts have been tested (with a duct blaster). Duct sealing and duct wrapping rebates hereafter apply only to work done by PTCS-trained HVAC technicians. In many homes, the entirety of a home's HVAC ducting is visible in a crawl space or attic. An insulation installer can know that ducts are intact, and could wrap them with opportune timing, but that is banned.

HVAC ducts should not be allowed to leak, but Energy Trust allows leaks to be deliberately maintained, if needed to achieve minimum fresh-air exchange, 7 ACH or greater at 50pa. See the requirement here, at AS 1.62. If one wants more fresh air, do it intelligently, with an HRV installation! Other absurdities are brought in, with the campaign to sell PTCS training. I will be out of this business, until it is fixed. If I find a detached duct, I will assuredly re-connect it, and might foil-tape it. Shame on me. No rebate. None deserved. Failed to test? Punish me.

Tuesday, March 17, 2009

Duct Joining and Sealing with Mastic

Duct sealing can be done at lowest material cost, and with assured complete air tightness, using a two-part tape method, or a simple brush-on or spray-on of mastic. This photo shows one duct element solidly installed with materials I judge to be Hardcast Two-Part: RTA adhesive, and DT 5300 mineral-gypsum-compound-impregnated fiber tape. A two-part joint has alignment strength that is comparable to that with Foilmastic tape, but stable alignment must be achieved by other means, before tape application. The method was easily applied where a small-diameter duct was at rest on blocks. Brush-on mastic has its place where duct joints are not under bending stress. Mastic covering is not suitable where a duct must be lifted for subsequent insulation wrapping.

Hardcast materials are conveniently available at GENSCO.

Monday, March 16, 2009

Duct Joining and Sealing With Foilmastic Tape

What is an insulation installer to do, if a customer has not found and hired a competent HVAC mechanic, to fix defective ducts, in advance of his work? I gamely did what had to be done, in this first trial of methods. A 16" diameter return-air duct has been re-routed, with some new, stronger ducts and elbows. Several detached joints were made stable, and were locked and sealed using Nashua Polyken 367-17 Foilmastic UL 181B-FX listed tape. GENSCO will be a good supplier of all elements of the job. No one offfered me a wrap and goop method, and I would have found that unsuitable here. I needed to progressively, experimentally and securely assemble the ducts. Wrap and goop is both too permanent and too insecure.

Foilmastic is useful for all joining and sealing of solid ducts. It is also useful as a means of flaring and stabilizing a flexible duct where it joins a solid duct. This flexible duct was not large enough to engage the steel duct. I cut 120 degree “flaps” that were drawn over the steel ducts, with good control of engagement. I taped the flaps down with a couple of full turns of 3” foil tape. A full round or two of poly-skrim-kraft tape completes the mating with insulating wrap. Several dollars of tape are involved. It is worth it.

A crawl space might incude a large number of supply-side ducts of variable diameter, with perhaps a need of detachability for access. I note the following in a 1996 report:

  • Duct mastic works, although cold and wet weather make it difficult to apply.
  • Workers don't like mastic. It ruins clothes and tools, especially when users are novices.
  • Tape-applied mastic seals well. These are the aluminum tapes with 15-mil butyl backing.
  • Air handlers are leaky.

These duct elements had been bound with duct tape, which of course was dried out and detached. Joints were stable but not secure. There were no leaks more significant than that occurring at the elbow joints. Foilmastic is used to assure joining strength, and sealing was not the first objective. If simple sealing were the objective, brush-on mastic would do, and all joints should be painted. Here, near the crawl apace entrance and with relatively good head room, Foilmastic was not the only choice. Please see the next posting.

At 4/12/2015, upon seeing this as a prominent find in search of Nashua Polyken 367-17, add referral to my newer views that most steel ducts should be replaced with well-set flex ducts. 

The process employs 367-17 tape only at steel connector-fittings. All joining of flex ducts is with very excellent Nashua 557 tape, having just-right adhesiveness. Why aren't these excellent Nashua tapes in most stores, displacing and eliminating most sales of awful "duct tape." Choose black 557 Pro-Grade UL Listed Duct Tape. I doubt that where sold as silver 557 "duct tape" at Home Depot and a few other stores, that it measures up. Why do most stores insist on selling non-professional junk?

Friday, January 9, 2009

Conditioned Crawl Space, First Experiment

In a very three-dimensional crawl space, with a trench and a gas furnace, Visqueen, 6-mil poly, whatever the cheap covering commonly available, does not suffice.

Here is a trial of 16-mil reinforced polyethylene called Goldentouch, from Americover. The material is superior to that offered by Basement Systems.

All seams are strongly attached and sealed with tough 1 1/2" width double-back butyl tape. Topside overlap is dressed with 4" width "vapor bond" sealing tape, matching the tough Goldentouch white vinyl.

The material cost here was about $500. 

Thursday, January 8, 2009

Kneewall Closet Air Barrier

This kneewall closet was to be insulated in compliance with new Energy Trust of Oregon requirements as follows:
Kneewall insulation, whether new or pre-existing, shall be covered with a durable, vapor permeable air barrier material to prevent air penetration of the insulation, and to ensure that the insulation is held in full contact with the wall cavity. Air barrier material shall be tested and labeled to meet Oregon fire protection standards. The air barrier material shall be permanently fastened so that it supports the kneewall insulation.

Insulation and drywall on the kneewall would suffice, but this closet is large enough to offer useful storage. With a complete envelope of insulation and house wrap, the space is conditioned, and the door is no longer challenged by cold and drafts. The floor is stuffed with a maximum of insulation.

House wrap is tried here as an economical barrier method. If durable and cheerful enough, it avoids a larger cost for drywall. This installation enclosing the outer wall and sloped ceiling (roof joists) has tight overlap of wrap with stapling at end walls, and only one other seam, sealed with Tyvek tape.

I have been confounded by the covering requirement, added by Energy Trust of Oregon without explanation or prior discussion with affected contractors. Technical support at Johns Manville denies that house wrap will have measurable effect on insulation R-value. I accept that there are two objectives. First Objective: blocking air infiltration if the kneewall lacks another air barrier, as without complete interior drywall and gasket sealing of access doors. Second Objective: as stated at the first page of the ETO Specifications, there is concern for occupant exposure to insulation fibers:
Insulation installed and receiving an incentive from the Home Energy Solutions (HES) program in attics, basements, garages, storage areas, or other areas where occupants go for routine maintenance or storage (Human Contact Areas), shall be covered with a vapor permeable air barrier to limit occupant exposure to insulation fibers. Unless a barrier (such as a wall) exists, fibrous insulation shall be covered. Fibrous insulation used as a dam around storage areas in attics shall be covered and extend at least sixteen inches from storage area. Attic hatches and knee wall-access doors insulated with fibrous insulation shall also be covered. All covering shall meet applicable codes.

The first objective might not dictate wrap on the outer wall or the sloped ceiling, and would apply whether or not the closet would ever be occupied. With this objective, there is concern that wrap is complete, with tape that securely seals all overlap. The Tyvek tape failed in this service, under blower coor conditions. See added comment below. It's adhesion is WIMPY. Surely all Tyvek tape should be recalled, as demands of adhesion are even greater for exterior use under siding. Johns Manville makes a tape for compatibility with its Gorilla Wrap, called JM SealIt, but my supplier does not stock it, and I could not buy it on my own. My supplier stocks Gorilla Wrap only in response to the new kneewall rules, and this suggests other installers are not taping seams or overlap. I don't yet know how I will respond to liability to my customer, for failed tape.

The second objective would dictate wrap only in a utilized closet, but on all insulation surfaces.

With either argument, air should be blocked in all kneewalls, even where access outside the kneewall is difficult. Where access is difficult, I think it would be better to just ensure the kneewall is air-tight on inside wall surfaces, as with drywall replacement of leaky paneling.

I have another concern related to the kneewall ruling. Often there are wall areas accessible on the outside, within an upper attic used for storage. It is painful to not find incentive to insulate those walls to R21 or more, with two layers, one crossing and covering wall joists. With encouragement to do this, would there be demand of outside covering with air barrier material?

If exposure to insulation fibers is the principal concern, what of floor insulation in an upper attic? I brought covering of attic-floor insulation into my discussion of house wrap, with Johns Manville technical support. I thought I might learn that floor R-value is diminished, especially with low-density loose-fill insulation, without a covering air barrier. A lid on that discussion is closed. I still entertain thought of laying manageable pieces of house wrap on an attic floor, especially as a block of loose-fill, whereby covering fiberglass batts, during handling, would not dirty their surroundings. I have much concern about fibers with cellulose and rock-wool insulation, and almost none with dense Johns Manville batts. I think the concern might serve to ban cellulose and rock wool as insulation in an attic floor.

By my trial (photo) I have illustrated confusion in the ETO Specifications. With this report, I ask for clarification. In the absence of clarity, I have foregone several jobs involving kneewalls.

At March 27, 2009, I add these comments:
Draft 2009 specifications from Energy Trust do not clarify intent of air barrier material. I think the ruling is still misdirected at covering insulation fibers so they won't be breathed. My observation of the failed tape seam in the closet described here, under minus 50 pascal blower door conditions, is that draft IS the issue. Tape releases under any pressure differential if an overlap is not tightly pinched. Often in unusable spaces of bungalow homes, the wall of the "bonus room" is gapped paneling. A tight air barrier is hard to achieve, especially where there is not a lower, outer kneewall, in tiny closets. Still, I will try, with use of more-agressive tapes. I do now have a roll of Johns Manville Gorilla Wrap tape. It is just 1.89" wide, hard to aim onto an overlap seam, and looks like the Tyvek tape. I doubt I will even test it. Certainly in the closet described here, added drywall will be the best solution, and housewrap was not needed. In tiny never-accessed closets, air sealing attempts outside kneewalls will fail. There, the correct solution is replacement or overlay of paneling, with good drywall.

At 1/24/2010 I add discovery of more history in the unexplained ETO rule. The Building Performance Institute, BPI, weighed in on this, in 2003. They say:
Insulation installed in kneewalls or other exposed vertical areas must be covered on the cold side with an air barrier such as plywood or housewrap to protect the insulation from wind-washing and free convection within the insulation. This measure is not necessary if rigid foam insulation is used.
To BPI, the issue is insulation effectiveness. They believe air stilling in insulation improves its effectiveness. I'm inclined to agree, but am overruled by experts at Johns Manville. They claim (wrongly I accuse) that even loose-fill insulation on an attic floor would have exactly the same thermal performance whether or not there is a covering that might still the contained air.

At 3/21/2010, I direct the reader to interpretation, and my related experiments:

At 11/16/2010, I report condition of the house wrap in this little-used closet.  All Tyvek housewrap tape has released. The customer still does not want to apply drywall, and I promised to just repair the one fallen-down panel. I will apply 3" width Vapor-Bond tape, by Americover.