Deck Construction FAQ Guide
1. Joist hangers must be attached with approved nails - deck screws not permitted
2. Footings must be 3xs the Dia. of the post with 12in of concrete below the post
3. Decks over 5 ft. high must have 6x6 posts or larger
4. Stairs - Open risers are permitted, provided that the opening between treads does not permit the
passage of a 4-inch diameter (I02 mm) sphere
5. R311.7.7 Handrails. Handrails shall be provided on at least one side of each continuous run of
treads or flight with four or more risers Type I. Handrails with a circular cross section shall have
an outside diameter of at least 1 ¼ inches (32 mm) and not greater than 2 inches (51 mm). Type
II. Handrails with a perimeter greater than 6 ¼ inches (160 mm) shall have a graspable finger
recess area on both sides of the profile.
6. R312.2 Height. Required guards at open-sided walking surfaces, including stairs, porches,
balconies or landings, shall be not less than 36 inches (914 mm) high measured vertically above
the adjacent walking surface, adjacent fixed seating or the line connecting the leading edges of
the treads.
7. R312.3 Opening limitations. Required guards shall not have openings from the walking surface to
the required guard height which allow passage of a sphere 4 inches (I02 mm) in diameter.
8. R502.2.2.1.1. Placement of lag screws or bolts in deck ledgers. The lag screws or bolts shall
be placed 2 inches (51 mm) in from the bottom or top of the deck ledgers and between 2 and 5
inches (51 and 127 mm) in from the ends. The lag screws or bolts shall be staggered from the top
to the bottom along the horizontal run of the deck ledger
9. R5.02.2.2.3 Deck lateral load connection. The lateral load connection required by Section
R502.2.2 shall be permitted to be in accordance with Figure R502.2.2.3. Hold-down tension
devices shall be installed in not less than two locations per deck, and each device shall have an
allowable stress design capacity of not less than 1500 pounds (6672 N).
·
10. Deck beams must be connected to the post with ½ in. diameter through bolts, post must be
notched so beam is supported by 1 ½ inches of wood - 2 bolts per post min.
DECK DESIGN
Design is calculated at 60 lbs. per square foot
FOOTINGS
Minimum 36" deep and 12" wide
SUPPORT POSTS
4 X 4 Allowed to a deck height of 4' above grade
6 x 6 required for decks above 4'
LEDGER BOARDS
Shall be attached directly to the house and thru bolted a
minimum 16" O.C. with ½” bolts
JOIST SPANS
All spans are based on the use of pressure treated lumber and
16" on center spacing
Maximum Spans
2 X 6 7' 8"
2 X 8 10' 2"
2 X 10 13' 0"
2 X 12 15' 9"
All joists must be supported by hangers both ends, unless support
by walls or beams.
GUARDRAILS
Required on all decks 30" or more above grade
Horizontal balusters must be a minimum of 36" above the deck surface
Vertical balusters are required & shall be placed allowing a maximum 4" space
HANDRAILS
Required on all stairs of 3 risers or more
Handrail height may be 30" minimum and 38" maximum
Guardrails (balusters) are required on stairs of decks over 30" above grade
POST SPACING
Joist Span
Beam Size
(2) 2x6
without 2' cantilever
(2) 2 X 8
without 2' cantilever
(2) 2 X 10
without 2' cantilever
(2) 2 X 12
without 2' cantilever
(3) 2 X 12
without 2' cantilever
6'
12'
14'
8'
10'
Based on maximum 2' cantilever
16'
5' 0"
4'3"
3'8"
3' 3"
n/a
n/a
6' I 0"
5' 11"
5' 3"
4' 5"
3' 9"
3' 4"
6'7"
5'7"
4' 10"
4' 3"
3' 10"
3' 5"
9' 0"
7' 9"
7' 0"
5' 10"
5' 0"
4' 4"
8' 5"
7'2"
6'3"
5' 6"
4' 11"
4' 5"
11' 6"
9' 11"
8' 11"
7’ 5”
6’ 5"
5' 7"
10' 3"
8' 9"
7' 7"
6' 8"
6’ 0"
5' 4"
14' 0"
12' 1"
10’ 10"
9' 1"
7' 9"
6' 10"
12' 10"
11' 10"
10'0"
8' 10"
8' 1"
17' 11"
14' 10"
1 11' 0"
1
13' 3"
12' 1"
11' 2"
10' 3"
4” maximum
opening for open
risers
9” Min.
Act 13 2004
3/8” Max Deviation between Steps
9” Run – 8 ¼” Rise
Open Risers – 4” Max
Stair Geometry
Handrails and Guards
Handrails