ledger not for decks

[Mr. Inspector]

I could use some help in finding somewhere in the 2009 IRC for ledger connections for a sunroom/addition floor. Lot's of things about deck ledgers for decks in the IRC but I can't find where ledgers are even allowed for anything else.

 

[rogerpa]

R502.6.2 Joist framing. Joists framing into the side of a wood girder shall be supported by approved framing anchors or on ledger strips not less than nominal 2 inches by 2 inches (51 mm by 51 mm).

R502.10 Framing of openings. Openings in floor framing shall be framed with a header and trimmer joists. When the header joist span does not exceed 4 feet (1219 mm), the header joist may be a single member the same size as the floor joist. Single trimmer joists may be used to carry a single header joist that is located within 3 feet (914 mm) of the trimmer joist bearing. When the header joist span exceeds 4 feet (1219 mm), the trimmer joists and the header joist shall be doubled and of sufficient cross section to support the floor joists framing into the header. Approved hangers shall be used for the header joist to trimmer joist connections when the header joist span exceeds 6 feet (1829 mm). Tail joists over 12 feet (3658 mm) long shall be supported at the header by framing anchors or on ledger strips not less than 2 inches by 2 inches (51 mm by 51 mm).

TABLE R602.3(1) FASTENER SCHEDULE FOR STRUCTURAL MEMBERS

ITEM	DESCRIPTION OF BUILDING ELEMENTS	NUMBER AND TYPE OF FASTENERa, b, c	SPACING OF FASTENERS
1	Blocking between joists or rafters to top plate, toe nail	3-8d (21/2" × 0.113")	—
2	Ceiling joists to plate, toe nail	3-8d (21/2"× 0.113")	—
3	Ceiling joists not attached to parallel rafter, laps over partitions, face nail	3-10d	—
4	Collar tie rafter, face nail or 11/4" × 20 gage ridge strap	3-10d (3" × 0.128")	—
5	Rafter to plate, toe nail	2-16d (31/2" × 0.135")	—
6	Roof rafters to ridge, valley or hip rafters: toe nail face nail	4-16d (31/2" × 0.135") 3-16d (31/2" × 0.135")	— —
7	Built-up corner studs	10d (3" × 0.128")	24" o.c.
8	Built-up header, two pieces with 1/2" spacer	16d (31/2" × 0.135")	16" o.c. along each edge
9	Continued header, two pieces	16d (31/2" × 0.135")	16" o.c. along each edge
10	Continuous header to stud, toe nail	4-8d (21/2" × 0.113")	—
11	Double studs, face nail	10d (3" × 0.128")	24" o.c.
12	Double top plates, face nail	10d (3" × 0.128")	24" o.c.
13	Double top plates, minimum 24-inch offset of end joints, face nail in lapped area	8-16d (31/2"× 0.135")	—
14	Sole plate to joist or blocking, face nail	16d (31/2" × 0.135")	16" o.c.
15	Sole plate to joist or blocking at braced wall panels	3-16d (31/2" × 0.135")	16" o.c.
16	Stud to sole plate, toe nail	3-8d (21/2" × 0.113") or 2-16d 31/2" × 0.135")	— —
17	Top or sole plate to stud, end nail	2-16d (31/2" × 0.135")	—
18	Top plates, laps at corners and intersections, face nail	2-10d (3" × 0.128")	—
19	1" brace to each stud and plate, face nail	2-8d (21/2" × 0.113") 2 staples 13/4"	— —
20	1" × 6" sheathing to each bearing, face nail	2-8d (21/2" × 0.113") 2 staples 13/4"	— —
21	1" × 8" sheathing to each bearing, face nail	2-8d (21/2" × 0.113") 3 staples 13/4"	— —
22	Wider than 1" × 8" sheathing to each bearing, face nail	3-8d (21/2" × 0.113") 4 staples 13/4"	— —
23	Joist to sill or girder, toe nail	3-8d (21/2" × 0.113")	—
24	1" × 6" subfloor or less to each joist, face nail	2-8d (21/2" × 0.113") 2 staples 13/4"	— —
25	2" subfloor to joist or girder, blind and face nail	2-16d (31/2" × 0.135")	—
26	Rim joist to top plate, toe nail (roof applications also)	8d (21/2" × 0.113")	6" o.c.
27	2" planks (plank & beam - floor & roof)	2-16d (31/2" × 0.135")	at each bearing
28	Built-up girders and beams, 2-inch lumber layers	10d (3" × 0.128")	Nail each layer as follows: 32" o.c. at top and bottom and staggered. Two nails at ends and at each splice.
29	Ledger strip supporting joists or rafters	3-16d (31/2" × 0.135")	At each joist or rafter

[TD=colspan: 4] Roof [/TD]



[TD=colspan: 4] Wall [/TD]



[TD=colspan: 4] Floor [/TD]

 

[Mr. Inspector]

So for a sunroom/ addition they cannot use a ledger. they would have to use joist hangers or a ledger strip right on the rim board. They can't build the sunroom/addition on a deck that is suported by a ledger that is to code for a deck, they would have to rebuild the deck without the ledger board and attach the joists direcly to the rimboard?

 

[Francis Vineyard]

I can't find where the code prohibits enclosing decks.

Francis

 

[cboboggs]

I don't think you would have to rebuild anything, you would just have to make sure the existing construction could support the increased loads.

 

[Sifu]

Would there necessarily be increased loads? Would the condition be potentially better since presumably the existing floor will not be subject to wet conditions any more? Aren't the uniform loads for a deck the same as would be for a sunroom? (40/10)

 

[rogerpa]

You said; "not for decks". Now you have a deck???

for ledger connections for a sunroom/addition floor

How is the existing deck supported at the house? Toe-nailed? Is it code compliant now? Lateral load connection?

R502.2.2.1 Deck ledger connection to band joist. For decks supporting a total design load of 50 pounds per square foot (2394 Pa) [40 pounds per square foot (1915 Pa) live load plus 10 pounds per square foot (479 Pa) dead load], the connection between a deck ledger of pressure-preservative-treated Southern Pine, incised pressure-preservative-treated Hem-Fir or approved decay-resistant species, and a 2-inch (51 mm) nominal lumber band joist bearing on a sill plate or wall plate shall be constructed with 1/2-inch (12.7 m) lag screws or bolts with washers in accordance with Table R502.2.2.1. Lag screws, bolts and washers shall be hot-dipped galvanized or stainless steel.

I doubt the sunroom would exceed 50 pounds per square foot design load.

 

[Mr. Inspector]

ledger not for decks

We have a 40psf ground snow load plus the dead load for the peaked roof plus the weight of the walls and windows coming down on the 2 sides of the deck. The end deck joists that are supported by the ledger would have to be beefed up to support the walls. Wouldn't this increase the load on the ledger?

 

[Mr. Inspector]

Yes the ledger is done by code for a deck.

I can't find where the code prohibits enclosing decks.Where does the code prohibit a car on a deck?

It's not a deck anymore. It's a floor. Would you let them support an interior floor with a ledger?

R502.6.2 Joist framing. Joists framing into the side of a wood girder shall be supported by approved framing anchors or on ledger strips not less than nominal 2 inches by 2 inches (51 mm by 51 mm).

It says "leger strip" not a ledger.

Where does the code say you can support floor joists and girders that are supporting walls and a roof woth a ledger?

 

[Yankee]

Yes the ledger is done by code for a deck.

I can't find where the code prohibits enclosing decks.Where does the code prohibit a car on a deck?

It's not a deck anymore. It's a floor. Would you let them support an interior floor with a ledger?

R502.6.2 Joist framing. Joists framing into the side of a wood girder shall be supported by approved framing anchors or on ledger strips not less than nominal 2 inches by 2 inches (51 mm by 51 mm).

It says "leger strip" not a ledger.

Where does the code say you can support floor joists and girders that are supporting walls and a roof woth a ledger?

Framing can ether bear a min of 1.5" on something or it can be hung with hangers. Figure out what the loads will be and the service conditions and go from there. Don't let the code sections intermingle and confuse you.

 

[Mr. Inspector]

But ledgers don't bear on anything or hung with hangers.

 

[Yankee]

So for a sunroom/ addition they cannot use a ledger. they would have to use joist hangers or a ledger strip right on the rim board. They can't build the sunroom/addition on a deck that is suported by a ledger that is to code for a deck, they would have to rebuild without the ledger board and attach the joists direcly to the rimboard?

I don't see where is disallowed to hang the joists from a ledger board, or bear the joist on a ledger board.

 

[Yankee]

Would there necessarily be increased loads? Would the condition be potentially better since presumably the existing floor will not be subject to wet conditions any more? Aren't the uniform loads for a deck the same as would be for a sunroom? (40/10)

The supporting system needs to accommodate the roof and its loads in addition to the floor loads. So if it is an existing deck, the girder/posts ma be inadequate.

 

[Francis Vineyard]

Rick there are many terms that are not defined in the code such as ledger board and others that have the dual duty as beams and headers. What we may do is analyze or pull from other applications for guidance; for example floor attached to masonry walls in R606.

In effect what happens is the band board will work as a girder and with the ledger board as a built-up beam. Could attach the ledger strip or hangers directly to the band board but would be more work to achieve the same result as adding a ledger board.

Deck is defined as a floor system and doesn't necessary have to be open to the exterior.

The new AWC DCA can be used as a reference where it prescribes attachments of beams but not girders to the ledger. Similarly where "ledgers" are nailed to wall studs to support stair landing the method is not specifically in the code and yet inspectors will require joist hangers for joist attached to this board!

FWIW we have residential garages with wood decks or floors constructed in accordance with the live load table.

Yankee was able to post twice by the time I could edit with my slow internet connection so there's some redundancy.

Francis

 

[Mr. Inspector]

Don't have my IRC with me but I know it says deck girders cannot be supported by a ledger. With this sunroom/addition they will have a girder with walls on it attached to the ledger. It seems to me that if you can't have a girder for a deck supported by a ledger you shouldn't have a girder that is supporting a floor, walls, and a roof to be supported by a ledger.

 

[Francis Vineyard]

Correct; ledgers cannot prescriptively support girders, however most likely existing deck rimjoist that will support the wall/ceiling/roof becomes a beam not a girder.

http://www.thebuildingcodeforum.com/forum/residential-building-codes/10812-irc-beam-girder.html?highlight=beam+girder

Francis

 

[Yankee]

Correct; ledgers cannot prescriptively support girders, however most likely existing deck rimjoist that will support the wall/ceiling/roof becomes a beam not a girder.http://www.thebuildingcodeforum.com/forum/residential-building-codes/10812-irc-beam-girder.html?highlight=beam+girder

Francis

I would agree

 

[Mr. Inspector]

Ok, so where is the table for beam spans if is not a girder?

 

[DRP]

The girder and header table is a table of uniformly loaded beam spans.

But, the ledger attachment specs are for a uniformly loaded ledger. I agree with you that it would be inappropriate to attach a beam, girder, header... a concentrated point load, somewhere along the length of a ledger that was designed for distributed loads. The connection of the ledger to the supporting structure in that immediate area may, or may not, be up to the task. IMO the beam supporting the wall and roof needs to have its' loads quantified and the connection of the beam to the supporting structure would then be designed according to the referenced AF&PA's NDS. I've been wondering id the bams supporting the wall could not be inserted through the rim to rest on the mudsill. The remaining ledger would then carry the joists, if perpendicular to the house, as the intended uniformly distributed load. WCDD also has uniformly loaded beam safe load tables but I think the first hill to climb is the one you were first focusing on, connection.

 

[Francis Vineyard]

Assuming a gable roof extending from the structure the beam supports the dead load of the wall (20 psf); the roof/ceiling load is split between the posts and wall of the structure. Another design to address is wind bracing with approved brackets or connectors in accordance with R602.10.9 (2009 IRC).

Shed roofs are similar.

Francis

 

[Mr. Inspector]

Thanks. it is a gable roof but even if it wasn't it still would be supporting part of the roof. I am going to tell them it must be attached to the rimboard with a hanger or dig in a pier against the foundation.

By the way can't find the word beam anywhere in the IRC. And the only place I can find "ledger" is for decks, so I can't see using ledgers for anything else.

 

[Francis Vineyard]

Does it matter? See Definition: Height, Story; ceiling height in basement; Drilling and Notching; floor framing fastening; floor sheathing table; etc..

Francis

 

[steveray]

The problem with 1/2" lags is they need to be embedded 4x the diameter...1-1/2" rim doesn't cut it.....or at least that is what the NDS or WFCM used to say

You said; "not for decks". Now you have a deck???How is the existing deck supported at the house? Toe-nailed? Is it code compliant now? Lateral load connection?

R502.2.2.1 Deck ledger connection to band joist. For decks supporting a total design load of 50 pounds per square foot (2394 Pa) [40 pounds per square foot (1915 Pa) live load plus 10 pounds per square foot (479 Pa) dead load], the connection between a deck ledger of pressure-preservative-treated Southern Pine, incised pressure-preservative-treated Hem-Fir or approved decay-resistant species, and a 2-inch (51 mm) nominal lumber band joist bearing on a sill plate or wall plate shall be constructed with 1/2-inch (12.7 m) lag screws or bolts with washers in accordance with Table R502.2.2.1. Lag screws, bolts and washers shall be hot-dipped galvanized or stainless steel.

I doubt the sunroom would exceed 50 pounds per square foot design load.

 

[peach]

We have a 40psf ground snow load plus the dead load for the peaked roof plus the weight of the walls and windows coming down on the 2 sides of the deck. The end deck joists that are supported by the ledger would have to be beefed up to support the walls. Wouldn't this increase the load on the ledger?

unless it's a flat roof, the roof snow load will be less than the ground snow load.