Lessons Learned With A Year-2009 Fakro Fire-Rated Attic Ladder, Much-Improved

To assess achievements in any job, it is helpful to note starting conditions that had been coped-with for many years,

My 17' Little-Giant-like aluminum ladder in stepladder mode, reached this high to a ceiling 114.5" above the concrete floor.

A 3/8" plywood flimsy skirt about the "hole" was 16" high, far taller than surrounding R19 loose-fill insulation. Somehow from the top step of a step ladder, one had to place weight upon the wobbly skirt, to hurdle over tripping electric power cables and to land on a single 24" path to the furnace platform. Furnace filter changes and more demanded safe access.

All of the landing area is over house heated space and should have remained R38, undisturbed. R38, at R2.2 per inch, demands 18" insulation depth, not achieved anywhere. If insulation over 10% of heated space is only R8 and the remainder were actually R38, the effective R-value is as 1/(Reff + 3) = .1/11 + .9/41. Reff = 29. If the remainder is only R25, Reff is 21. In Metro Portland Oregon at Fall 2023, there is a $1.25 per sq ft rebate of cost paid for added attic floor insulation. Installation specifications: Existing insulation must be R-18 or less. Must insulate to R-38 or greater or the fill accessible cavity.

I would do further math to prove qualification at <R18, where space with no insulation, under the furnace and in general near roof eaves amply brings down the average.

  The insulation space under the furnace platform is 10 1/4". I will build framing in new safe passage to the furnace that again is 10 1/4" tall. I want no trip-edges. Where the found loose-fill so-readily collapses to 3 1/2" depth, new insulation should be in the form of tough and resilient R25 fiberglass batts 24" x 48" parallel to the trusses, for total then of almost R38. Very importantly in this, all space with no insulation, must be filled. This might demand temporary jacking of the furnace off of the messy flooring, two heavily-nailed layers of 7/16" OSB.

The new, level plywood floor is non-tripping, although 19/32" plywood does flex some.

Get on now to the core purpose of this post, considering lessons learned with a unique attic ladder.

A fire-rated ladder must not be compromised by a gap about the ladder frame, only concealed by wood trim. This framing is trimless as seen in the full-scale drawing that follows.

Limit arm upper pivots are 5/16" x 2 1/2" lag screws embedded strongly in the ladder rough frame (well-strengthened truss bottom elements).

See that the ladder frame is tight against the perfectly-square rough frame. No shims. No gaps. With removal of a few screws, the ladder is fully removable, not bonded in place. At some future time, the ladder might be in the way of furnace replacement or removal.

The clear no-snags ladder opening with a 22" frame width will pass large bags of insulation now-needed. Know that no large garage like this could have other than 24" on-center framing. With truss framing, this is the best-possible accessibility. Be very grateful to have this last-of-its' -kind-on-Earth, wonderful attic ladder.

The deployed ladder steps are quite rigid, The two rails meet the floor equally with soft, gripping leveler legs.

The invoiced ladder cost is $419, now a bargain where inflation has doubled costs of weatherization since 2009.

See that the upper section of the ladder is highly customized. To have the Top Step I now demand for customer safety, I blocked the little step section, raised above the door, in a sturdy birch-plywood frame. The springs to-be-added can't be strong enough to have the heavier assembly slam-close as is foolishly and firmly a Fakro fire-rating feature. Fakro then will not offer a door latch that would reduce demands upon the springs.

I have been tasked then with invention of the latch, using good Central-European hardware purchased from one-time ladder manufacturer Calvert USA, in 2011. Calvert USA built excellent ladders in Maryland until 2016, including fire-rated ladders  that did not cost extra.

This is the currently-offered Fakro LWF 54" ladder shown with 30" frame width. 

$805 at Home Depot. A large fraction of this cost is in individual FedEx or UPS shipments from an Illinois warehouse.

See much-steeper 66° fixed angle, and large springs obstructing the opening. The door linkage is at a tripping-point, no down-stability, ready to lift and slam with a nudge. The needed pretty handle is absurdly placed, with barely enough clearance for finger-grips.

Pay attention to a successful further evolution in nature of a tenting rest.

A screw protruding from the left stile engages the tenting rest slot. Stability of the tent is dependent on having the tent center of gravity well behind the tent pivot, the center of the step section hinge at left in this photo. Imagine a tenting rest serving any attic ladder, perhaps that  drawn-on (darker) below the leveler leg here.

Study the dangerous factory-default deployment of this ladder at door angle 66°.

The better as-built installation is almost perfectly as drawn in the project bid. All installers of attic ladders should have such facility in planning. Surely architects demand this. Why should anyone want a ladder for its thoughtless cheapness?

Learn to follow the example of Swedish MidMade ladders in the location of lower pulls for the 

balancing springs.

Want the upper and lower pivots of limit arms to be at the same elevation, as low as possible. See multiple drilled-in positions for lower pivots upon the door face. Each one-inch shift from the 60° position set, brings the door steeper by approximately 2°. Choose least-steep as the factory default.

Please know that I have successfully installed Fakro fire rated ladders of current production, with 60° default, springs resident on the door and pretty-good slam closure. I have wished these ladders could have door latches for more-firm sealing. Here is the installation of Fakro LWF 25/54 Model 869719, costing $770 in May 2022, and costing $855 in November 2023. Surely the customer now with the LWF 22/54 of 2009, has  gotten a better deal.

Here is the stowed condition, showing spring leverage to pull fully closed. This works! Fakro should care to learn from my innovation, and has not.

Here see a door pull at the door opening end. There is no latch above. The door must self-close. See that installation requires facility with patching of drywall including fill of gaps to the steel edging that perfects frameless installation.

See more elements of the plastic Fakro Pull, as also a latch. I have had two of these from Fakro, not knowing what they are good for. The two long bosses at top in this view would need to be located very precisely by holes drilled in the opening (back) header of the ladder frame.  The mating of the latch halves would be by strong slam, and release by very hard pull. I despair of installing this with sufficient accuracy, and don't trust long-term durability.

The slam closure is better with a smaller ladder 47" frame. Be convinced of invention, with this video of the 47" ladder: https://www.youtube.com/watch?v=YJ4pg_exdvs.  With the easy-reach 47" ladder, there was no interest in tenting.

See a similar YouTube demonstration, year 2012, with a Calvert USA ladder and a ceiling nearly eleven feet up, in a home born as a warehouse of the 1905 Lewis & Clark Centennial Exhibition, in Northwest Portland, Oregon: https://www.youtube.com/watch?v=yBX8seprIO8.

Best fire-rated attic ladders are now wanted from manufacturer MidMade, in Sweden. None are on-offer, where imported by Conservation Technology, in Baltimore , MD. I am engaged in a campaign for change in this:

 https://docs.google.com/document/d/1PNS5irHuzUnGs3juhaudSvQrfubrlL1GkrWgHqdg09I/edit?usp=sharing

All Residence Attic Ladders Must Be Fire-Rated

 Please accept this as a wake-up call from a global misunderstanding:

https://codelibrary.amlegal.com/codes/willcounty/latest/willcounty_il/0-0-0-48114 

The link brings up a specific regional ordinance, in Illinois.

 150.060 FIRE RESISTANT CONSTRUCTION REQUIREMENTS.

   (A)   All conditioned spaces shall have all interior wall and ceiling surfaces covered with a minimum of one-half inch gypsum wallboard or approved equal. One inch nominal solid paneling shall not be required to have a drywall backing.

Who may argue that this doesn't apply in every home, in every jurisdiction, not excusing doors of attic ladders? It can't matter that rules for attic ladders in those jurisdictions may be forgiving. Failed enforcement is met with non-availability of suitable, affordable ladders. It must be believed that resistance to conflagration at every point, makes a difference. 

Plunker Access Has Been Treated Correctly

Here is an example of my writing and invention, at this blog. I improve upon persisting builder foolishness that despite a fragile and endangering gob of R30 insulation, is only R5.7.

This frame is 22.8” x 31.4”. The R38 unfaced batt is nicely square-cut 22” x 23”.

The fraction of drywall area covered by the batt is 22*23/22.8*31.4 = 0.707.
1/(Reff + 3) = 0.293/3 + 0.707/41
Reff = 5.7

Reff + 3 is the total heat transfer resistance number, and the inverse, U = 1/(Reff + 3), is 
U = 0.11

I'm all-in for 5/8" drywall in a factory-produced less-expensive and safer alternative, almost invisible and not to be hidden away within a closet. Perfection of a drywall cut with inserted steel edges is the same as I offer for attic ladder installations. The hatch here illustrated is over the garage of a modern home in Oregon City, Oregon, the subject of this blog post upon value of thoughtful attic access. Must I do better, against flame that may penetrate small gaps?

U-Value calculation for the hatch plug assembly:

Consider only the materials of the 1 1/2” framing 14%, and Rockwool, 86%. R4.3 per inch, R6.4. The R-value of wood is about 0.94 per inch, 1.41.

1/(Reff + 3) = .14/(1.41 + 3) + .86/(6.4 + 3) ; Reff = 5.1

Add three and invert, for U-value: 0.12.

Multiply this American U-value by 5.7, to obtain European U = 0.7

Drywall or better on doors of attic ladders too!

Until now I have been blind to nonsense where a hard-to-find and expensive fire-rated attic ladder is considered only for a garage with attic space that is in-common with attics of the rest of the house. A not fire-rated door typically has top and bottom facings of 1/4" MDF, wood edges and blocking, and well-fit pieces of factory-cast expanded polystyrene foam. It is not at all tolerant of fire!

At play is the simple enforcement of Building Codes. Current Energy Codes foolishly and hurtfully demand that ladder insulation value must match the surrounding attic floor R value. There has never been reason an attic ladder as a door, should have better energy retention than any exterior door. I must renew my campaign for r5portals.

Don't be taken in by foolish instruction that an attic access is a sin. An R5 hatch or ladder has smaller energy-replacement cost than any exterior door. Achievable savings in any practical improvement are of the order of just a dollar per year, as thoroughly presented at r5portals, and as I presented for proposed  2016 revision of the International Energy Conservation Code. I was not respected and was not heard by judges helped-along in their needfully-hasty deliberations by ever-present lobbyists pinch-penny for the National Association of Home Builders. Prevailing new rules rules demand insulation values not achievable with practical fire-rated doors. Safe building codes must rule.

A fire-rated ladder can be compromised by thoughtless installation, big gaps all around, poorly hidden by flimsy wood or plastic trim, not air-tight despite careful gasketing. Here is frameless and air-tight trimming of the ceiling cut, that I practice, applied with a Swedish MidMade fire-rated ladder:

I admit not knowing how a door with thirty minute fire rating is built. See that a strong, square, tight edge of the ceiling cut is built by grouting-in pieces of steel angle.

Here is the inside appearance of a MidMade ladder thus framed. The rough frame, out of sight, is tightly fit to the ladder frame. There are no missed opportunities of placing full stuffing of insulation. A floor super-insulated forever, brightly lighted and clean, adds very much value to a home. Let a tall attic be your expansive carpentry shop, comfortable part of the day almost year-round. Make rugs.

Flexible Grout For Sale

 For me, attic floor sealing opportunities occur randomly. Here I am working at the edge of an attic ladder now fully installed. Before I can place flooring, I must fully fill floor joists with insulation. Before that I must fill the large gaps at hallway wall headers. The flexible grout I prepare in my kitchen from powders and acrylic liquid, is reserved for use in drywall patching of the hallway ceiling.

Use instead Custom Fusion Pro Tile grout  readily available in any big box store. Choose color White. My grout and Custom grout are chemically very similar. They work as a putty the consistency of creamy peanut butter. Applied with a bit of pressure to a water-wetted gap, expect full-depth filling and stable bridging that hardens quickly, permitting recovery of excess with a trowel, and wetted-sponge cleanup if wanted. My grout is sandable, almost as easily as ordinary drywall compound, or formable to any desired texture pattern. Learn more at a blog promoting this; http://plasterrepairhowto.blogspot.com/ .

Fingers are readily washed for no-harm handling of my iPhone. Tools include a 3" flexible-blade trowel and a spray bottle for wetting of gaps.

Use of can foam for gap filling here, is absurd. Foam skins instantly without penetration and wet contact, rarely with full sealing. Expensive applicator guns are useless for intermittent application, so hard to clean up, involving dangerous chemicals, quickly ruined.

Kraft facing on batts is absurd. Here it hid the wall header gaps with no sealing effect. 

Some gaps are really large; this abused as a wiring passage. With the trowel, push in some rips of the wispy fiberglass, for one-step grout filling.

This is the so-often crumpled downward face of kraft-faced insulation. Never intimate. Often allowing energy-driven air circulation, defying insulation value. I peel off and dispose this trash. Kraft facing defies careful, tight placement of insulation, and should be abolished. It is ineffective as an air seal and usually detracts from insulation value.

2x4 Framing Build-Out To 2x6

This is the most-read blog post  of individual Phillip Norman, of Lake Oswego, Oregon, USA.

(a grand-daughter draws a best smile)

Surely this post is of value to more than the few who have offered comments. I hope that an introduction will improve participation. I will share your credited story related to this, or to any of my posts. I welcome and will share criticism, where I might mislead.

Please consider virtue in the accurate and strong build-out of 2x4 to 2x6 thickness in this exterior wall section of my 1955 home in Portland, Oregon. Here is that build-out immediately upon demolition of the wall formerly separating the kitchen from an on-foundation concrete back porch. Found 2x4 framing in this exterior wall is strongly thickened to 2x6 with added 2x2s upon plywood box-beam webs. New outside wall framing is 2x6.

This photo shows an initial setup with horizontal 2x6 segments pushed out to the the exterior sheathing.

Want instead an uninterrupted 2x4 at the floor, upright, shimmed-out 1/2" just like the 2x4 at the ceiling. Want ability to nail floor moulding anywhere. Want least obstruction through the 2x6 sill plate, for angle-drilled plumbing. 

Here is my kitchen in a nearly-complete condition, September, 2018. Added depth of exterior walls was important too, to better framing of windows and a door, and simplified  plumbing and wiring.

Google the title of this post: 2x4 Framing Build-Out to 2x6 .

Find no one else offering what I do, employing only available dimensional lumber as-produced, and plywood rips. 2x2 is usable for plane perfection regardless of curl.

Summary graphics that follow, and the math of insulation values and heating costs are presented in this document:

• My 2x4 Framing Build-Out to 2x6

Please find virtue in my simple Insulation Math. Find important conclusions in the applied math of the above-linked document, including:

• I have achieved average R22 for a net of all kitchen exterior wall area, the same for new 2x6 walls and the 2x4 built out to 2x6. This is R-value as the inverse of carefully computed U-values. R value of employed insulation is nearly the same.

Here is the fix:

With clarity in what I do, I may digress to the bigger picture.

Detailed records of my construction process are in job photo albums:

• Expansion onto the on-foundation back porch
• Kitchen completion

I had despised drop-ceiling headers over kitchen cabinets. Such headers are awful heat bleeds in most homes, where at exterior walls they are not accessible for insulation. Too often, none of the headers are filled with insulation. I have the opportunity to expand my kitchen 40% with modest effort where the little kitchen exited to the back yard via a concrete porch fully on-foundation. 

It was a crummy little kitchen, and held down the usefulness of the house, beyond being the last room in my house where I had not demolished interior drywall to accomplish data and power wiring improvements, plumbing replacements and tight R15 insulation.

In this one room I would accomplish R22 wall insulation in 2x6 framing.

See my build-out to 2x6 thickness of an existing 2x4 wall. At top place an on-flat 2x4 and 1/2” plywood rip. Stitch on lengths of 5” rips of 1/2” plywood as composite beam webs. Place 2x2s true vertical and flat, leaving 1/2” thermal breaks of both the 2x framing and the webs. The 1/2” gaps behind 2x2s enable simple running of wires, without steel plates to mess up drywall flatness.

My kitchen overhaul occurred in three stages, working by myself while completing all asked work as a general contrator:

Expansion Onto Porch, 8/2014 to 4/2015

Planning, 4/2015 to 7/2017

Completion, 7/2017 to 10/2018

Serious about this in late Summer 2017, I have reset the wall build-out to employ an upright 2x4 at the floor, for better baseboard attachment opportunity, and insulation a bit better.

I will have a much better kitchen, in a home that inspires possibilities with solidly-built homes of the 1950s. Details here are near-final. I do all work except cabinetry fabrication.

My circuit breaker panel is just beyond the garage wall that rounds this corner to the right. Most of the new kitchen wiring passes through the thickened South wall, with no need of nail-stop plates. See plumbing drains and vents well-reimagined in the crawl space below. All plumbing resides over the crawl space; none over the inaccessible former back-porch slab. Walls of the new half-bath will be elements of kitchen cabinetry, bolted to uninterrupted tile floor.

At left see invention of a module of wiring and plumbing devices that will plug into a careful rectangular cut through the back of the cabinet base for the kitchen sink. At right see some of the safe wiring opportunity, behind 2x2s of an outside wall bump-out to 2x6. Want that hidden wiring is fully revealed by removing outer/ top insulation batts.

Angle-drilling of kitchen sink water and drain lines is aided by the thickened 2x6 wall above.

The high end of house drain and vent piping, for a time, was at the laundry in the garage and at  the added half-bath.

See a more-elevated high point of the drain plumbing where a 1 1/2" ABS drain P-trap was added to collect consensate of the high-efficiency gas furnace and of a heat pump water heater. The kitchen overhaul with attendant new plumbing, enabled other important home improvements.

While exposed, the built-out framing was a laboratory of insulation methods, sharing photos in conversation with Insulation Institute .  I started out with an exceptional exterior wall judged to be R_total = 5, U = 0.2 not counting added value of wall joists and to-be-added insulation batts. To a generally-applicable R3 value of airtight sheating inside and outside, add  R2 value of Celotex sheathing . Exterior air tightness is achieved both at well-set old-growth cedar siding, and at overlap of Celotex edges. Start with less than half the conductivity and heating cost of common, cheap, non air-tight construction, Rtotal = 2.5, U = 0.4.

Walls built this way are to be treasured and preserved. I'm not sure what should be done with more-ancient walls, hopelessly leaky, hollow, cobweb strewn, with structural defects and dangerous wiring, ruined of insulation value. I suspect though that salvageable homes are determinant not by age, but by investment at time of construction.

Where is the pride of any employee or contractor of the US Department Of Energy paid to support residential energy efficiency, when USDOE Home Energy Scores treat all exterior walls without some insulation stuffing, as of paper, R_total = 0.4, U = 2.5 ? This perhaps-deliberately fuels older-home demolition regardless of solid construction. This is applied for all insulation opportunities, exterior walls, ceilings and floors. It encourages false claim that very-huge energy savings can be achieved by a blow-and-go scammer foolishly just adding some partial insulation atop wiring, plumbing and structural messes, if the home is not demolished.

The subjects with Insulation Institute  have been layering of batts to kill framing thermal shorts, full batt containment to avoid air circulation, and lack of value where insulation does not fully fill available space.

I wait, and wait, for recall of misinformation in this NAIMA instructional video of year-2012 . I bought and here tested a bag of the yellow Certainteed R13 insulation placed by the championed installer. Please watch the video, and see that the installer takes great care to not press edges beyond joist faces. I just don't know how to do that, making a fluffy batt 3" thick look like it fills the cavity space, as it must. It seems that alone among insulation manufacturers, Rockwool (formerly Roxul) , makes batts specified for a framing depth, that reliably fill the space. Look closely at the beginning of the video to glimpse Rockwool as exemplary insulation.

In my 2x4 garage wall, here is a length of Certainteed unfaced insulation wrongly rated as R13 in a 2x4 wall. It has been placed here for more than a year, in incomplete communication with NAIMA, North American Insulation Manufacturers Association. At 2016 hearings for revisions to 2015 International Energy Conservation Code, NAIMA defended code-allowed underfill of framing, defeating my proposed requirement of full filling always, by overfill that accommodates small-batt tolerances














In fact, R13 batts NEVER fill 2x4 framing. Where gaps will exist all around a batt, then with low flow resistance for air. Air circulation, driven by energy convection and outside wind pressures, may reduce insulation value to zero. There is no reason this should be allowed.

At last rounding this corner with drywall, I apply last-minute grouting of a vent annulus, with my always-available flexible grout. See that Rockwool R15 insulation  thoroughly fills the space, accurately cutting to width from 23"x 93" batts. Do the math on cost of this Rockwool vs. the experimental Certainteed R13 with no value, for one 16" oc frame bay, batt area 14.5*92/144 = 9.3 sq ft. The Rockwool cost $649 per 1000 sf. The R13 cost $397 per 1000 sf. The one batt cost, 9.3 sq ft, is $6, vs. $3.70. Proper code must keep a silly person from pocketing the negligible difference in installed cost. A DIY home owner must never be tempted to do wrong in a cheaper choice, by believing a "For 2x4 Framing" label on a crummy R13 bag.

Rounding the corner from built-out 2x6, to an ordinary 2x4 garage wall, report upon a layering trial to the right of that plumbing vent bay now filled with shaped R15. Where I have added a bath fan and overhead light junction box, 14/2 romex leads between a new 2G switch box and the attic, sandwich the wires between Rockwool AFB batts. See that R15 Rockwool is uniformly a bit thicker than 3 1/2". Two layers of AFB batts are 4" thick except as pressed in at edges, but better too thick for the space, than too thin.

I think insulation installers wrongly do not expect to find a family of batts that in layers, add up to fill the space, giving promised R-value.  AFB batts about R8 are not sold as suited for layering with object sandwiching.  2x6 walls may be filled with R23 Rockwool batts, or when necessary, with layered AFB:  R8 and R15.  2x4 walls may be filled just-barely, with R15 Rockwool batts, or when necessary, and perhaps better always, with two layers of AFB. Layering of manufactured consistent batts to deal with odd cavities, is not just good practice. Rockwool batts do not part, and hacked cuts make a big mess of a job, with puzzle pieces that challenge patience and result in deficient R-value. 

In new 2x6 walls, begin with AFB batts. there is certain ability to stuff an inch of effective insulation behind a crossbar that allows outlet placement distant from a 2x6 joist.

Here again see my trusty commercial bread-cutting knife, used for all cutting of batts. Cutting in and around friable Rockwool batts is easier and more precise than in stranded fiberglass batts. Where we admire honest, uniform thickness and easy shaping of Rockwool batts, also celebrate discarding of ill-conceived kraft facing as a leaky, crummy "vapor barrier." 

We need combinations of mineral wool batts that may sandwich wiring, as parting is just too awful.  One R15 batt and one AFB batt, or one R23 batt. nicely fill a 2x6 space. Doubled AFB batts as sandwiching in a 2x4 wall have excessive overfill. One needs many screws to pull in the drywall with compression.

Overfill is not the goal. Overfill is demanded only where batts have unreliable thickness, to get complete fill always.

With full demolition of drywall at the garage 2x4 wall, see dripped flexible grout from wall header sealing in the attic long ago. Plaster the gap now.

Seal the wall header fully.

For good reason and as demonstration of good example, buy a new coil of Resource Conservation Technology BG32 EPDM gasket.

The BG32 gasket consumed here will cost me less than $6. With flexible grout sealing of existing drywall, it will block a leakage path to the attic that is poorly accessible, and was not sealed before.

At the somewhat conditioned garage wall, insulate with R15 and layered-R8 Rockwool.

Finish GP Densarmor drywall pieced-in, using flexible grout and Structolite plaster, over joints well stitched with screws and backing lumber. Set joint paper tape in 24" lengths, at ceiling and wall corners only.












Date: 2/23/2018. Ideal condition for wall observation with an infrared camera. And, I don't own one. A camera investment of about $10,000 can have no economic return to me. I leave no voids, always maximizing insulation value. I believe there was nothing more to do, to  improve comfort and reduce operating costs at these exterior walls. I have at least the R23 before-framing-allowance achievable in 2x6 framing, with tight mineral wool batts. The modified 2x4 wall is yet-better insulated. And, ask now, by how much, and how much some defensible difference, matters. Least-rigorous math has 1/Reff = 0.25/5.2 + 0.75/23, Reff = 12.4 for simple 2x6 walls with 25% framing factor, R23 batts. Use Insulation Math for this home, Annual cost of heat = $2.4*Area*U. U = 1/(R + 3),   Wall area 250 sq ft, Annual cost of heat = $39. If I could somehow have R23 framing, the annual cost of heat would be $23. I'm being glib about window and door much larger heat losses accepted as imperative. Have I done something wrong to accept $16 per year unavoidable heat loss for walls in this room?

I will not be shamed by extremes in this current blog post of Insulation Institute: 
3/21/2019, Mineral Wool: A Solution to Thermal Bridging 
See what they might have me do as exemplary use of mineral wool batts:

 I see wasteful failure to fill 2x6 framing space. I see exterior insulation that can't be part of sensible and strong construction. I see failure to be realistic about thicknesses and labeling of on-offer batts, 2" R8, 3.5" R15, 5.5" R22, 7" R30. There are no 3" batts. There is no acknowledgement that mineral wool batts can't be parted to go around wires or pipes. Then offer layering, for example:. 2" + 3.5" = 5.5", ~R22.