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Bathroom design layout specifications: this article discusses current best design practices for residential bathrooms, including typical bathroom layouts, measurements & clearances for mirrors, showers, tubs.
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Bath Design Best Practices
We discuss anti-scald for bathrooms, bathroom flooring, ventilation, and lighting as well as bathroom safety glass needs.
This article series discusses current best design practices for kitchens and bathrooms, including layout, clearances, work space, and accessible kitchen and bathroom layout, clearances, turning space, grab bars, controls, etc. We include advice on choosing and installing kitchen countertops, cabinets, and kitchen or bathroom flooring, sinks, and other plumbing fixtures and fixture controls such as faucets. A list of kitchen and bath product manufactures and sources is included.
As described and detailed in Chapter 6 of Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) :
Bathroom Design Basics
A well-designed bathroom is comfortable to use, safe,
durable, and easy to clean. Space planning revolves around
the main fixtures and their required clearances. Proper
clearances are critical to avoid problems such as banged
elbows at a sink placed too close to a wall or difficult
access to the tub faucet.
Bathroom safety concerns should be paramount in design decisions
and material choices. For example, choose only
nonskid flooring types and select tub and shower controls
with foolproof antiscald protection (MIXING / ANTI-SCALD VALVES).
Avoid designs with
sunken tubs or tub surrounds with steps, both of which are
hazards.
Also remember that following code is not a guarantee
of safety. For example, while it is legal to place bathroom
lighting circuits downstream from the GFCI outlet,
it is unwise since anything that trips the GFCI will also
plunge the bathroom into darkness.
The following recommendations are based on guidelines
first published by the National Kitchen and Bath
Association in 1992. While accessible design principles
are provided separately below, NKBA now incorporates
these principles into their recommendations for all
projects.
Lavatories: Sink Clearances, Heights, Measurements
Clearances. Locate each sink so its centerline is at
least 15 inches from a wall and 30 inches from the
centerline of a second sink. The minimum walkway
shown in front of the sink may not allow full
accessibility (see Figure 6-16).
Height. While the standard vanity or sink height is
30 to 32 inches, 34 inches is a better compromise
between shorter and taller users. If a bath has more
than one vanity, set one at 30 to 34 inches and the
other at 34 to 42 inches high.
[Click any image or table to see an enlarged version with additional detail, commentary & source citation.]
Mirror Height Specifications for Bathrooms
The bottom edge of a mirror over a
vanity should be no more than 40 inches above the floor,
or 48 inches if the mirror is tilted forward.
Shower Dimensions, Clearances & Measurements for Bathrooms
Clearances: Allow a minimum 21-inch walkway
(30 inches preferred) from the front of the shower
stall to a wall or fixture. These clearances may not
allow full accessibility.
Size: Provide a minimum clear floor space inside
the shower stall of 34x34 inches, preferably
36x36 inches or larger.
For optimal accessible-bathroom comfort and
safety, increase the size to 36x42 inches to
48 inches, which allows space for the user to step
out of the stream of water to adjust the temperature
(Figure 6-17).
Neoangle Showers: Neoangle showers are popular space
savers, but the showering area is reduced in size
due to the cut-off corner. The size of the corner
cut varies from one model to another, with
some cutting significantly into the shower
space. For comfort, neoangles should be at least
42x42 inches.
Showerhead Location: Locate the showerhead supply pipe
72 to 78 inches above the finished shower floor. The
installed showerhead will be 4 to 6 inches lower. If a
handheld showerhead is used, it should be no higher
than 48 inches at its lowest position.
Seating in Shower Stalls: Shower stalls should include a bench or
seat that is 17 to 19 inches high and a minimum of
15 inches deep. The seat should not encroach on the
minimum 34x34-inch floor space.
Doors for Showers: Shower doors must open into the bathroom,
not into the shower stall.
Controls for Showers: Locate controls 38 to 48 inches off the floor
and offset toward the room so they are accessible from
both inside and outside the fixture.
Bathtub Clearances & Measurements
Clearances. Allow a minimum 21-inch walkway
(30 inches preferred) from the open side of the tub to
a wall or fixture. These clearances may not allow full
accessibility.
Steps to a tub. Do not build steps leading to
a bathtub or raised tub platform. These create a
serious hazard. It is much safer for users to sit on
the lip of the tub or platform and swing their legs in.
Sunken tubs are also a hazard. Safety rails should be
installed to help users get in and out of any tub
configuration.
Controls. Offset controls toward the outside of the
tub so they are accessible from both inside and outside
the fixture.
Bathtub controls should be no more than
33 inches high.
If a handheld showerhead is used,
it should be no higher than 48 inches at its lowest
position (Figure 6-18).
Antiscald Protection Advice for Bathrooms
Protect all tubs and showers
with a pressure-balancing valve or thermostatically
controlled valve to limit water temperatures at a faucet or
showerhead to 120°F or less. Recommend that homeowners
set water heaters to no more than 120°F as an added
precaution.
Details about anti-scald protection and devices are found
Toilets and Bidet Layout & Clearances for Bathrooms
Clearances. Fifteen inches is the allowable
minimum from the centerline of toilets and bidets
to a fixture or wall, while 17 to 18 inches will create
a more comfortable space (Figure 6-19).
Sixteen
inches is the minimum for full accessibility as long
as there is sufficient transfer space in front or on
the side
for sizing
details and other bath ventilation information).
Electrical Receptacles for Bathrooms - GFCI Needed
All bathroom receptacles must be GFCI
protected. All light fixtures above a tub or shower
must be rated for damp locations (tub) or wet locations
(shower). Switches must not be reachable from within
a tub or shower. Many bathrooms are wired so that all
the lights go out if a GFCI is tripped.
Although this is
allowed by code, it is neither safe nor convenient for the
homeowners.
Where possible,
provide natural lighting as well from a window or skylight
area equal to at least 10% of the floor area.
Glass Safety Requirements in Bathrooms
All glass used in a tub or shower enclosure
or other glass applications within 18 inches of the
floor should be safety glazing, such as laminated glass,
tempered glass, or an approved plastic.
Typical Bathroom Layouts
Bathrooms are divided into three main centers of activity:
lavatory/grooming, toilet/bidet, and bathing/showering.
In smaller bathrooms, these all share one common space,
while in more spacious rooms, the grooming area or
toilet area may be separated to allow greater flexibility
and privacy for multiple users.
Larger spaces also allow
for greater storage, such as a linen closet, within the
bathroom space. Typical bathroom layouts with minimum
dimensions for comfortable use are shown in Figure 6-20.
Marley Engineered Products
www.marleymeh.com
Ceiling-mount bath fans and general kitchen and room
exhaust fans
Panasonic
www.panasonic.ca/English/ventilationfans
Low-sone, Energy-Star-compliant ceiling-mount, inline,
and wall bath fans.
- - This article includes excerpts or adaptations from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) , by Steven Bliss, courtesy of Wiley & Sons. Adapted with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) .
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Reader Comments, Questions & Answers About The Article Above
Below you will find questions and answers previously posted on this page at its page bottom reader comment box.
(Sept 11, 2012) John Broadfoot said: What is the specification of glass used in bathroom mirrors
Reply:
Some local codes for public buildings, schools, etc. may require safety glass, or an application of a safety film on mirrors, particularly large or full length units.
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In addition to any citations in the article above, a full list is available on request.
Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
"Are Functional Handrails Within Our Grasp" Jake Pauls, Building Standards, January-February 1991
Access Ramp building codes:
UBC 1003.3.4.3
BOCA 1016.3
ADA 4.8.2
IBC 1010.2
Access Ramp Standards:
ADA (Americans with Disabilities Act), Public Law 101-336. 7/26/90 is very often cited by other sources for good design of stairs and ramps etc. even where disabled individuals are not the design target.
ANSI A117.4 Accessible and Usable buildings and Facilities (earlier version was incorporated into the ADA)
ASTM F 1637, Standard Practice for Safe Walking Surfaces, (Similar to the above standards)
ASHRAE resource on dew point and wall condensation - see the ASHRAE Fundamentals Handbook, available in many libraries.
2005 ASHRAE Handbook : Fundamentals: Inch-Pound Edition (2005 ASHRAE HANDBOOK : Fundamentals : I-P Edition) (Hardcover), Thomas H. Kuehn (Contributor), R. J. Couvillion (Contributor), John W. Coleman (Contributor), Narasipur Suryanarayana (Contributor), Zahid Ayub (Contributor), Robert Parsons (Author), ISBN-10: 1931862702 or ISBN-13: 978-1931862707
2004 ASHRAE Handbook : Heating, Ventilating, and Air-Conditioning: Systems and Equipment : Inch-Pound Edition (2004 ASHRAE Handbook : HVAC Systems and Equipment : I-P Edition) (Hardcover) by American Society of Heating, ISBN-10: 1931862478 or ISBN-13: 978-1931862479 "2004 ASHRAE Handbook - HVAC Systems and Equipment The 2004 ASHRAE HandbookHVAC Systems and Equipment discusses various common systems and the equipment (components or assemblies) that comprise them, and describes features and differences. This information helps system designers and operators in selecting and using equipment. Major sections include Air-Conditioning and Heating Systems (chapters on system analysis and selection, air distribution, in-room terminal systems, centralized and decentralized systems, heat pumps, panel heating and cooling, cogeneration and engine-driven systems, heat recovery, steam and hydronic systems, district systems, small forced-air systems, infrared radiant heating, and water heating); Air-Handling Equipment (chapters on duct construction, air distribution, fans, coils, evaporative air-coolers, humidifiers, mechanical and desiccant dehumidification, air cleaners, industrial gas cleaning and air pollution control); Heating Equipment (chapters on automatic fuel-burning equipment, boilers, furnaces, in-space heaters, chimneys and flue vent systems, unit heaters, makeup air units, radiators, and solar equipment); General Components (chapters on compressors, condensers, cooling towers, liquid coolers, liquid-chilling systems, centrifugal pumps, motors and drives, pipes and fittings, valves, heat exchangers, and energy recovery equipment); and Unitary Equipment (chapters on air conditioners and heat pumps, room air conditioners and packaged terminal equipment, and a new chapter on mechanical dehumidifiers and heat pipes)."
1996 Ashrae Handbook Heating, Ventilating, and Air-Conditioning Systems and Equipment: Inch-Pound Edition (Hardcover), ISBN-10: 1883413346 or ISBN-13: 978-1883413347 , "The 1996 HVAC Systems and Equipment Handbook is the result of ASHRAE's continuing effort to update, expand and reorganize the Handbook Series. Over a third of the book has been revised and augmented with new chapters on hydronic heating and cooling systems design; fans; unit ventilator; unit heaters; and makeup air units. Extensive changes have been added to chapters on panel heating and cooling; cogeneration systems and engine and turbine drives; applied heat pump and heat recovery systems; humidifiers; desiccant dehumidification and pressure drying equipment, air-heating coils; chimney, gas vent, fireplace systems; cooling towers; centrifugal pumps; and air-to-air energy recovery. Separate I-P and SI editions."
Principles of Heating, Ventilating, And Air Conditioning: A textbook with Design Data Based on 2005 AShrae Handbook - Fundamentals (Hardcover), Harry J., Jr. Sauer (Author), Ronald H. Howell, ISBN-10: 1931862923 or ISBN-13: 978-1931862929
In addition to citations & references found in this article, see the research citations given at the end of the related articles found at our suggested
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Carson Dunlop Associates provides extensive home inspection education and report writing material. In gratitude we provide links to tsome Carson Dunlop Associates products and services.