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Air Flow Pathways in a Leaky Exterior Wall

I found some interesting air leakage evidence while remodeling my bathroom

Posted on Jun 1 2016 by Allison A. Bailes III, PhD

This spring I spent a lot of hours in my bathroom. I was sick. Really. I was sick and tired of having an outdated bathroom that was falling apart. So when my wife hit the road one Monday in late April to drive across the country, I got out my wrecking bar. The lead photo shows what it looked like at the end of my first full day of demolition.

I opened up the plumbing wall first. Lots of fun stuff, there. But the real fun came when I opened up the exterior wall. The four termite-damaged studs were part of that fun, but something else was even better.

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Image Credits:

  1. Energy Vanguard

Tile a Barrier-Free Bathroom

How to create a roll-in shower

Master tile setter Tom Meehan combines a time-tested mortar base with a modern waterproofing membrane and a linear drain to create an easy-access shower.

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A Green Bath Retrofit: From Structure to Finish

Brattleboro, VT

Apr 1 2010 By Peter Yost | 2 comments

General Specs

Location: Brattleboro, VT
Living Space : 50 sqf
Cost (USD/sq. ft.): $70/sqf

This cost includes the floor framing and the new finish on the kitchen ceiling. Although it includes some labor costs, it does not include the author's labor.


  • Fluorescent ceiling and bath vanity fixtures
  • Water Efficiency

  • 1.6 gpf toilet
  • 1.6 gpm Delta H2O Kinetics showerhead
  • Cool water collection system (plastic pail is used to collect approximately 1 gallon of cool water before each shower; this water is used to rinse shower surround)
  • Indoor Air Quality

  • Cotton shower curtain/polyester shower liner
  • High-performance exhaust fan (on rheostat for 25–100 cfm output)
  • Green Materials and Resource Efficiency

  • Cast-iron tub reused
  • Original yellow birch flooring reused
  • Cut-off rigid insulation used as cavity insulation on exterior tub surround walls
  • Toilet salvaged from water-efficiency testing program
  • Beadboard wainscoting salvaged for bath or porch reuse
  • Making a 50-square-foot full bathroom work

    Our second-floor, 50-square-foot full bathroom provides the only bathing in this 100-year-old house, so we had to make it work. We wanted to make the room feel bigger and deal with what we were sure was structural damage around the toilet. Underneath several layers of failing linoleum, we found the original beautiful yellow birch flooring, but also floor framing so compromised that the toilet waste line was "structural."

    Peter Yost

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    Image Credits:

    1. Peter Yost
    2. GNA
    3. Steve Baczek

    Convert an Attic into a Luxury Bath

    Seattle, WA

    Jul 17 2009 By Kristian Kicinski | 1 comments

    General Specs

    Location: Seattle, WA


    Architect: VELOCIPEDE architects inc
    Builder: Jan Henderson and Joyce Hurford, Blue Marlin Construction


    • Added new space above existing footprint – avoided site disturbance

    General design and construction

    • Consolidated laundry and bathroom into more accessible space
    • Open plan, including curbless shower
    • Well-designed storage; efficient layout

    Building envelope

    • Damp-spray cellulose insulationThermal insulation made from recycled newspaper or other wastepaper; often treated with borates for fire and insect protection.
    • Wood windows made regionally in Bend, Ore.
    • Wet- and dry-blown cellulose insulation made of 100% recycled content (R-54 ceilings)
    • Cotton batt insulationInsulation, usually of fiberglass or mineral wool and often faced with paper, typically installed between studs in walls and between joists in ceiling cavities. Correct installation is crucial to performance. (100% recycled content)
    • Advanced framingHouse-framing techniques in which lumber use is optimized, saving material and improving the energy performance of the building envelope.


    • Radiant heat in walls and floor
    • New gas-fired boiler and water heater (Viessman); existing radiators remained at most rooms; PEXCross-linked polyethylene. Specialized type of polyethylene plastic that is strengthened by chemical bonds formed in addition to the usual bonds in the polymerization process. PEX is used primarily as tubing for hot- and cold-water distribution and radiant-floor heating. tubing in floor and walls of new construction


    • dual-flush toilet (1.6/0.8 gpfGallons per flush. Measurement of water use in toilets. Since 1992, toilets sold in the United States have been restricted to 1.6 gpf or less. The standard for high-efficiency toilets (HETs) is 1.28 gpf.)
    • EPA-compliant showerhead and faucets
    • drainwater heat recovery (Gravity Film eXchange)


    • Skylights and window bank supply natural lighting
    • Antique light fixtures


    • Energy- and water-efficient washer/dryer

    Interior finishes

    • Ceiling of sustainably harvested cedar
    • Recycled chalkboard-slate floor
    • 100% recycled glass wall tiles
    • Paper/resin composite countertop (Richlite, FSCNonprofit organization that promotes forestry practices that are sustainable from environmental and social standpoints; FSC certification on a wood product is an indicator that the wood came from a well-managed forest. certified/recycled paper)
    • Plant-based oil/wax wood finish (OS Hardwax)
    • Pacific madrone cabinets (lumber from storm-felled city trees)
    • Low-toxic paints and sealants

    Exterior finishes

    • Fiber-cement siding over rainscreenConstruction detail appropriate for all but the driest climates to prevent moisture entry and to extend the life of siding and sheathing materials; most commonly produced by installing thin strapping to hold the siding away from the sheathing by a quarter-inch to three-quarters of an inch.

    An attic conversion brings daily tasks closer together without expanding this home's footprint.

    Leslie and Heather, the owners of a 100-year-old 1 1⁄2-story house in Seattle’s Capitol Hill district, were tired of hiking downstairs in the middle of the night from their attic bedroom to the first-floor bathroom. To make matters even more inconvenient, the laundry room was still farther below in the basement. Leslie and Heather wanted to simplify their lives and their floor plan by putting all three spaces on one level.

    Lessons Learned

    Communication, creative thinking, and compromises pay off
    No matter how thorough you are, there's always a good chance of miscommunication. Our specs called for FSCNonprofit organization that promotes forestry practices that are sustainable from environmental and social standpoints; FSC certification on a wood product is an indicator that the wood came from a well-managed forest.-certified lumber, but the framer purchased ordinary lumber with "Certified" in the lumber grading stamp. We failed to explain what FSCForest Stewardship Council. An independent, nonprofit organization that promotes responsible forest management through the use of a third-party certification process. FSC certification includes a chain-of-custody requirement that tracks sustainability of wood products from growth to end use. meant—to us it's a common acronym, but to the builder it was an unknown term. We did manage to get FSC-certified cedar beadboard for the finished ceiling.

    Working in existing spaces often demands creative solutions. The geometry of the house's existing roof fixed the ridge, and we could only raise the north slope so much. By placing TJI rafters at 32 in. o.c. and bearing directly on wall studs, we eliminated window headers, lowered our eave plate height, and provided enough ceiling height.

    The existing subfloor was at the same level throughout the second floor, so we installed a subtle ramp in the passage from bedroom to bathroom to gain the 1 1/2-in. height necessary for the mortar bed that encases the PEXCross-linked polyethylene. Specialized type of polyethylene plastic that is strengthened by chemical bonds formed in addition to the usual bonds in the polymerization process. PEX is used primarily as tubing for hot- and cold-water distribution and radiant-floor heating. and supports the slate.

    Further resources

    To see a panoramic view of this bathroom, visit

    — Kristian Kicinski is an architect in Seattle, WA (additional information provided by George Ostrow, president, VELOCIPEDE architects inc)

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    Image Credits:

    1. Charles Bickford/Fine Homebuilding
    2. VELOCIPEDE architects inc
    3. Paul Perreault

    Deep Energy Makeover: One Step At A Time

    Brattleboro, VT

    Apr 27 2009 By Peter Yost | 0 comments

    General Specs and Team

    Location: Brattleboro, VT
    Bedrooms: 3
    Bathrooms: 1.5
    Living Space : 1800 sqf

    Construction cost: approximately $85,000; roughly 75% of labor was free (homeowner and family)

    Construction/wiring: Peter Yost, Christian Yost, Israel Yost, Nathan Yost (sort of a New England version of Brothers Strong)
    Plumbing and heating: Temple Plumbing and Heating, Dummerston, Vt.
    Architect: Steve Baczek, RA


    Walls (first floor): concrete block; uninsulated
    Walls (second floor): wood frame; uninsulated
    Windows: single-pane double-hung wood
    Roof: unvented slope (steeper pitch of gambrelThis is a gable roof with two pitches, the bottom pitch being steeper than the top. The term gambrel is also used to describe the hing leg of a horse, with a angle at the joint that looks like a gambrel roof, or much more likely, the other way around.), vented attic (lower-pitch gambrel); old, loose-fill fiberglass in very poor condition (approx. R-5)
    Basement: Uninsulated cast-concrete, broken concrete floor (one section of bare dirt); vented front-porch crawl space with bare dirt; single-pane awning, divided-lightTrue divided light sash have small panes of glass separated by muntins. Because large pieces of glass used to be difficult (or expensive) to make, older houses have windows with two, four, or six small lights per sash. These multiple-light sash are also called "divided-light sash" or sometimes "divided-light windows." windows
    Garage: detached

    Foundation: basement, 3-1/2-in. open-cell spray foam in stud wall (R-12); crawl space, unvented 1-1/2-in. polyisocyanurate insulation board on perimeter walls sealed with approximately 1-in.-thick spray foam, double 6-mil poly sealed to perimeter walls (R-10)
    Walls (first floor): 3-in. high-density, closed-cell spray foam on exterior (R-20+)
    Walls (second floor): 2x4 studs; 3-1/2-in. fiberglass batt and 1-in. XPSExtruded polystyrene. Highly insulating, water-resistant rigid foam insulation that is widely used above and below grade, such as on exterior walls and underneath concrete floor slabs. In North America, XPS is made with ozone-depleting HCFC-142b. XPS has higher density and R-value and lower vapor permeability than EPS rigid insulation. insulation board (R-17+)
    Windows: ;ow-e, double-glazed, wood-framed (U=.33, SHGCSolar heat gain coefficient. The fraction of solar gain admitted through a window, expressed as a number between 0 and 1.=.32)

    Roof: sloped ceiling, R-19 fiberglass batts with interior 1-in. XPS (total R-24); flat ceiling, interior 1-in. XPS, criss-crossed triple-layer batt insulationInsulation, usually of fiberglass or mineral wool and often faced with paper, typically installed between studs in walls and between joists in ceiling cavities. Correct installation is crucial to performance. , one fiberglass, two cotton batt (total R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. : 44+); cathedral ceiling in kitchen addition, R-38 polyisocyanurate 5.5-inch SIPs
    Garage: detached (no change)


    Pre-remodel K-factor (number of heating degree days covered by one gallon of fuel oil): 7.5
    Post-remodel K-factor: 15.85
    Pre-remodel blower door: > 4,000 cfm @ 50 Pascals
    Post-remodel blower door: 1,240 cfm @ 50 Pascals (still working on air-sealing issues)
    Annual energy use: 77 MMBtus/yr (pre-remodel not known)

    • 88% AFUE fuel-oil boiler
    • Superinsulated stainless-steel jacketed indirect-tank water heater
    • Under-counter LED kitchen lighting
    • CFL or hard-wired throughout home (except three cluster fixtures in living/dining room and kitchen
    • Energy Star ceiling fan in master bedroom
    • No central air conditioning

    Water Efficiency

    • Energy Star dishwasher
    • Front-loading clothes washer
    • Low-flow toilet: 1.0 gpf pressure-assist
    • Hands-free electronic kitchen faucet

    Indoor Air Quality

    • High-efficiency spot exhaust fans in kitchen and baths
    • High-efficiency 24/7 whole-house exhaust
    • Carbon monoxide detector in basement next to boiler

    Green Materials and Resource Efficiency

    • Non-paper-faced gypsum board on all walls
    • Driveway redone with free-draining, locally quarried bluestone
    • All structural wood removed from home during renovation salvaged
    • 2x3s (basement) and 2x2s (reclad system first floor) ripped from ReNew salvaged lumber
    • All interior trim reused
    • Bedroom and kitchen shelving made from salvaged school furniture

    An eight-year remodel of a 100-year old house produces a healthy home that will last another century.

    When my wife Chris and I bought this nearly 100-year-old home in 2000, we knew we had our work cut out for us: virtually no insulation; original single-pane windows; a failing main bathroom; just four circuits of knob-and-tube wiring; no laundry hook-up; and a dysfunctional 12x12 kitchen with three windows and four doorways.

    Lessons Learned

    We feel pretty fortunate. The problems with the original house kept it on the market for a long time and meant a really good purchase price for us. And the money we put into performance upgrades brought the cost pretty close to market value of any old house in our area.

    We confronted many challenges and learned quite a few lessons along the way. The replacement sashes didn't work well with our out-of-square jambs, so more than a few windows are still leaky where they don't make continuous contact along the sill. The SIPs kitchen floor is just as high performance as the roof, but in the middle of winter, walking from the uninsulated floor with basement below versus walking on the SIPs floor is quite a shock; more insulation is needed to offset the floor being on piers over outside air.

    Perhaps the biggest disappointment is in the air-tightness of the home. Despite careful planning of the overlaps of insulation and air-sealing systems, there is still a lot of untraced air leakage. Continuous pathways in the ungrouted block walls and tricky details at the four gambrel valleys are the likely culprits - more-targeted blower door testing should give us a better idea. As with most old homes, this will always be a work in progress.

    Peter Yost is director of residential services for BuildingGreen, LLC

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    Image Credits:

    1. Daniel Morrison
    2. Peter Yost
    3. Steve Baczek

    A Skylight Cheers Up an Attic Bath

    Posted on Dec 22 by Christina Glennon


    Of all the rooms in the house, this attic bath used to have the worst layout.

    Dark and cramped, it measured less than 5 ft. wide and 11 ft. long, and had a bathtub squeezed between floor-to-ceiling sidewalls.

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    Breathing Fresh Air Into Bathroom Ventilation

    Posted on Dec 18 by Christina Glennon


    Powerful, quiet exhaust fans and their smart switches have made it easy to avoid mold, mildew, and stale air in the bath

    This overview of bathroom ventilation explains how to size and select a fan that's quiet and efficient.

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