Living Small in a Big Way- Tiny Homes
Wenatchee Home Inspections
Tiny home seems to be more and more appealing to many looking for a comfortable space on a small footprint and a smaller budget. The problem is the codes have to now deal with these smaller than normal spaces. Enter the 2018 IRC and Appendix Q. Now, most areas have not yet adopted the 2018 code and it may be a while for many. For Washington, the anticipated effective date for the 2018 codes is July 1, 2020.
Tiny home design from www.tumbleweedhouses.com
Here is a couple of section from the code to give you a feel and what can be expected.
From the 2018 IRC Appendix Q-
About this appendix:
Appendix Q relaxes various requirements in the body of the code as they apply to houses that are 400 square feet in area or less. Attention is specifically paid to features such as compact stairs, including stair handrails and headroom, ladders, reduced ceiling heights in lofts and guard and emergency escape and rescue opening requirements at lofts.
Below are some of the big sections-
2018 IRC SECTION AQ101
This appendix shall be applicable to tiny houses used as single dwelling units. Tiny houses shall comply with this code except as otherwise stated in this appendix.
Ceiling height is the big one typical building code requires 7 feet height with some exceptions. But in the tiny home, this overall height has been reduced.
AQ103.1 Minimum ceiling height.
Habitable space and hallways in tiny bouses shall have a ceiling height of not less than 6 feet 8 inches (2032 mm). Bathrooms, toilet rooms and kitchens shall have a ceiling height of not less than 6 feet 4 inches (1930 mm). Obstructions including, but not limited to, beams, girders, ducts and lighting, shall not extend below these minimum ceiling heights.
Exception: Ceiling heights in lofts are permitted to be less than 6 feet 8 inches (2032 mm).
Next big concern is the loft, which is where most are going to sleep in these homes-
SECTION AQ104 LOFTS
AQ104.1 Minimum loft area and dimensions.
Lofts used as a sleeping or living space shall meet the minimum area and dimension requirements of Sections AQ104.1.1 through AQ104.1.3.
AQ104.1.1 Minimum area.
Lofts shall have a floor area of not less than 35 square feet (3.25 m2).
AQ104.1.2 Minimum dimensions.
Lofts shall be not less than 5 feet (1524 mm) in any horizontal dimension.
AQ104.1.3 Height effect on loft area.
Portions of a loft with a sloped ceiling measuring less than 3 feet (914 mm) from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required area for the loft.
Exception: Under gable roofs with a minimum slope of 6 units vertical in 12 units horizontal (50-percent slope), portions of a loft with a sloped ceiling measuring less than 16 inches (406 mm) from the finished
And getting up to the loft-
AQ104.2 Loft access.
The access to and primary egress from lofts shall be of any type described in Sections AQ104.2.1 through AQ104.2.4.
Stairways accessing lofts shall comply with this code or with Sections AQ188.8.131.52 through AQ184.108.40.206.
Stairways accessing a loft shall not be less than 17 inches (432 mm) in clear width at or above the handrail. The width below the handrail shall be not less than 20 inches (508 mm).
The headroom in stairways accessing a loft shall be not less than 6 feet 2 inches (1880 mm), as measured vertically, from a sloped line connecting the tread or landing platform nosings in the middle of their width.
AQ220.127.116.11 Treads and risers.
Risers for stairs accessing a loft shall be not less than 7 inches (178 mm) and not more than 12 inches (305 mm) in height. Tread depth and riser height shall be calculated in accordance with one of the following formulas:
1. The tread depth shall be 20 inches (508 mm) minus four-thirds of the riser height.
2. The riser height shall be 15 inches (381 mm) minus three-fourths of the tread depth.
Here is a great article by Glenn Mathewson discussing the changes in the code in regards to tiny homes.
As we will see tiny home will challenge zoning laws and many municipalities are trying to come to grips with these new little kids on the block. This new appendix will at least give you some guidance on these homes.
"True life is lived when tiny changes occur."
If you find any errors or have additional information that would expand on any code, building standards or manufacturer requirements please let me know.
NCW Home Inspections, LLC is a Licensed Washington State Home Inspection service located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Oroville, Cle Elum, East Wenatchee, Quincy and many more…
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