floor and roof connections to masonry walls

TEK 5-7A © 2001 National Concrete Masonry Association (replaces TEK 5-7 and TEK 17-5 )

NCMA TEKNational Concrete Masonry Associationan information series from the national authority on concrete masonry technology

FLOOR AND ROOF CONNECTIONS TOCONCRETE MASONRY WALLS

TEK 5-7A Details (2001)

Keywords: connections, floor systems, hollowcore,joists, ledger, loadbearing concrete masonry, pocket,roof systems, trusses

INTRODUCTION

Floor and roof systems for use with loadbearing struc-tural concrete masonry walls serve three primary functions:they transmit the vertical dead load and live load to the bearingwalls; they function as diaphragms, transmitting lateral windand seismic loading through the walls to the foundation; andthey act to support the walls from out-of-plane loads. Inaddition to these structural functions, floors and roofs shouldprovide a satisfactory barrier to the transmission of sound,fire, and heat. The many types of floor and roof systems in usetoday are designed to satisfy all of these requirements in aneconomical manner.

CONNECTIONS

The transfer of loads between diaphragms and wallsrequires the proper design and detailing of the connectionlinking these elements. Connections critical to the integrityof a structure. The connections detailed herein addressminimal requirements. Additional requirements may benecessary in some locals, particularly where earthquake andhigh wind forces are to be resisted. The four primary types ofconnections, each having specific advantages, include:· Direct Bearing Connection – The direct bearing connec-tion is often the simplest type of connection. This connec-tion is used at the top of concrete masonry walls or when achange in wall thickness provides a ledge with sufficientbearing area as shown in Figure 1.· Pocket Connection – A pocket connection consists offraming the floor or roof system into a void in the masonrywall. This detail is used when masonry continues above(either as part of the wall or as a parapet) the connectionlocation and eccentricity is to be minimized. Care must betaken to insure that the use of a pocket does not interfere withthe continuity of the vertical reinforcement in the wall.· Hanger Connection – When it is desired to maintain thecontinuity of the wall for structural, aesthetic, or construc-tion reasons, a wall hanger can be used to suspend the roof or

floor system. Hangers are generally anchored to a wallthrough a joint and into a bond beam. However, hangersapproved for direct attachment to the surface of a masonrywall are also available.· Ledger Connection – As with hangers, ledger connec-tions minimize the impact on the continuity of a masonrywall. A ledger connection reduces the necessary pre-plan-ning and does not unduly impact the mason’s work as opposedto a pocket connection; thereby reducing the number of fieldmodifications.

Note: Most of the connections herein depict flashing forwater penetration resistance which should be used in all exteriorwalls. Normally flashing is not provided in interior walls.

FLOOR AND ROOFING SYSTEMS

Several materials are common to roof and floor con-struction. Wood, concrete, and steel are among the mostfrequently used framing materials in these applications.

Wood SystemsWood framed floors and roofs are common in residen-

tial and low-rise construction. It is imperative when con-structing a wood-framed system that it not be in directcontact with the concrete masonry. Wood in contact withmasonry materials may absorb moisture present in the con-crete masonry causing the wood to rot. To prevent theresulting unwanted decay, the lumber used should be pres-sure-treated, naturally decay resistant, or have a moisturebarrier placed between the wood and the concrete masonry.

Steel SystemsSteel-framed roofs using steel bar joints are very com-

mon in commercial structures because they are capable ofspanning long distances. Steel bar joists typically use pock-eted or ledger connections to concrete masonry walls. Pro-prietary systems that use concrete masonry units as a fillerbetween the steel joists are also available.

Concrete SystemsConcrete slabs can take many forms, including pre-

stressed, precast, and cast-in-place construction. Dependingupon the size and number of stories associated with a given

Provided by:Cinder & Concrete Block Corporation

Wood joist

Anchorage as required

Toenail or tie as required

Reinforced bond beam

Sill (pressure treated

Concrete masonry wall

or provide moisture barrier)

Blocking or band joistSuperstructure

Reinforced

staggered anchorDouble (shown) or

Ledger

Joist hanger

bolt as required

Sheathing

Wood joist

Solid or filledunit to supportflashing

bond beam

Grout stop

at 32 in. (814 mm)

Cavity fill or other

1 in. (25 mm) partiallyopen "L" shaped headjoints for weeps

Drip edge

mortar collection device

2 in. (51 mm) deep


Bond beam

Wood Truss

Notch/pocket

Provide gap or moisturebarrier as required

Reinforcement

at 32 in. (814 mm)

Drip edge

joints for weeps

partially open1 in. (25 mm)

"L" shaped head

collection device

Cavity fill orother mortar

inside of faceshellStop flashing at

o.c.

Reinforced

Joist hanger; fasten as required by

Wood joist

Sheathing

bond beam

hanger manufacturer

Cavity fill or other mortar


collection device

Drip edge

4 in. (102 mm) unit (solid or filled) tosupport flashing


Void/pocket

unit to support flashing

Concrete masonry bond beam

Fire-cut end of joist(as required)

provide moisture barrierPressure treated or

Reinforcement

Sheathing

Solid or filled masonry

Grout stop

1 in. (25 mm)

"L" shaped headpartially open

joints for weeps

Drip edge

at 32 in. (814 mm)o.c.

other mortarCavity fill or

collection device

Stop flashing at inside of faceshell

Wood joistFigure 1—Direct Bearing Wood Floor Joist (ref. 2)

Figure 2—Direct Bearing Wood Floor Joist

Figure 3—Wood Floor Joist Hanger (ref. 2)

Figure 4—Wood Floor Truss Hanger (ref. 2)

Figure 5—Wood Floor Joist With Pocket

Figure 6—Wood Ledger and Hanger

Figure 7—Wood Floor Truss Pocket (ref. 2)

Blocking or band joist

Sill (pressure treated or

Anchorage as required


Wood joist


Provide gap or moisturebarrier as required

provide moisture barrier)

of faceshellStop flashing at inside

Sheathing

as required

Drip edge

open "L" shaped head1 in. (25 mm) partially

joints for weeps

Cavity fill or other mortarcollection device

(solid or filled) to4 in. (102 mm) unit

support flashing

Toe nail or tie at 32 in. (814 mm)


Wood truss

Bearing truss hanger;fasten as required by hangermanufacturerConcrete

4 in. (102 mm) unit (solid orfilled) to support flashing

other mortarCavity fill or

collection device

"L" shaped head

1 in. (25 mm)partially open

joints for weeps

Drip edge

at 32 in. (814 mm)


o.c.

masonry wall

Bond beam

Anchor bolt or


Sill (pressure treated or

specialty anchoras required

provide moisture barrier)

code or useToenail per

rated connector

o

o

o

+

++

+

Reinforced bond beamConcrete masonry wall

as requiredUplift connectorMoisture barrier

Anchor bolts spaced as required


angleSteel


to steel Decking attached

required forangle as

shear transferdiaphragm

bolted to wallSteel ledger angle

Isolation joint


Steel bar joist welded orbolted to ledger angle

at 32 in. (814 mm)


Drip edge

Wood Nailer with anchor bolts

Sloping sheet metal copingcap with cont. cleat. each side

Attachment strip

Grout cores solid at anchor bolts

Counter flashing

Stop flashing at inside offaceshell (see TEK 19-2A)

CantParapet flashing

SealantRoofing membrane

Steel bar joist weldedor bolted to bearingplate

Sealant

at 32 in. (814 mm)

Standard unit withinside faceshell and


1 in. (25 mm) partiallyopen "L" shaped head

part of web removed

joints for weeps

Drip edge

collection device

plate with anchoraround joist steelSolid unit notched


Masonry wall

Grout stop

Parapet flashing

Attachment strip

Counter flashing

CantSealant

cap with cont. cleat. each sideSloping sheet metal coping

Wood Nailer with anchor bolts

SealantRoofing membrane

or bolted to bearingSteel bar joist welded

plate

joints for weepsReinforced bond beam

Drip edge

at 32 in. (814 mm) o.c.


open "L" shaped head1 in. (25 mm) partiallycollection device

Wall ties (typ.)

Insulation

Reinforced lintel

Steel shelf angle

Sealant at top offlashing unless self

tuck into mortar jointadhearing flashing or

(114 mm) max. cavity2 in. (51 mm) min. to 4 / in. 1

2

Figure 8—Wood Roof Truss with Top Plate (ref. 2)

Figure 9—Wood Roof Truss with EmbeddedStrap Anchor (ref. 2)

Figure 10—Steel Joist Direct Bearing on Cavity Wall

Figure 11—Steel Joist with Pocket (ref. 3, 4, 5)

Figure 12—Steel Joist with Ledger Angle

Figure 13—Steel Joist at Sidewall

NATIONAL CONCRETE MASONRY ASSOCIATION To order a complete TEK Manual or TEK Index,2302 Horse Pen Road, Herndon, Virginia 20171-3499 contact NCMA Publications (703) 713-1900www.ncma.org

project, one concrete framing system may have unique ben-efits over another. For example, hollow core prestressedslabs can be erected quickly, without the need for formworkor shoring. Where sufficient space is available at the job site,precast slabs can be formed in stacks on-site, starting with theroof slab and using the top surface of the lower slab as theform for the next slab. Once cured, the precast slabs are liftedto their final location. The use of cast-in-place concretefloors and roofs, because of the time needed for forming,pouring, finishing, and curing, requires a building plan whichis large enough to permit the masonry work to progress in onepart of the structure while the floor in another area is com-pleted.

Precast hollow core slab

Hooked shear bar grouted in slab keyway

of faceshell (see TEK 19-2A)Stop flashing at inside

or filled) to support flashing4 in. (25 mm) unit (solid

Topping if requiredat 32 in. (814 mm)



Drip edge

collection device

Bearing stripHooked bar in wall at shear

Reinforcedbond beam

bar (not required if verticalreinforcement at this location)

Grout stop

o.c.

Precast hollow core slab

Reinforcement with hookson both ends grouted

of faceshell (see TEK 19-2A)Stop flashing at inside

or filled) to support flashing4 in. (25 mm) unit (solid

Topping if requiredat 32 in. (814 mm) o.c.



Drip edge

collection device

Hooked bar in wall at shear

Reinforcedbond beam

bar (not required if verticalreinforcement at this location)

Grout stop

Grouted cells at location ofshear bar

into broken core

Figure 14—Concrete Hollowcore at Bearing (ref. 3) Figure 15—Hollowcore at Sidewall (ref. 3)

REFERENCES1. Architectural and Engineering Concrete Masonry De-tails for Building Construction, TR-95. National ConcreteMasonry Association, 1973.2. Concrete Masonry Homes: Recommended Practices.U.S Department of Housing and Urban Development, Officeof Policy Development and Research, 1999.3. Design for Dry Single-Wythe Concrete Masonry Walls,TEK 19-2A. National Concrete Masonry Association, 1998.4. Flashing Details for Concrete Masonry Walls, TEK19-5A. National Concrete Masonry Association, 2000.5. Generic Wall Design for Single-Wythe LoadbearingWalls. Masonry Institute of Michigan, 2000.

Provided by:Cinder & Concrete Block Corporation

Barbara Resimont

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floor and roof connections to masonry walls

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