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Proper Use of Masonry Joint

Reinforcement and Accessories

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Proper Use of Masonry Joint Reinforcement and Accessories

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Purpose and Learning Objectives

Purpose: Ensuring proper use of methods and materials allows masonry walls to perform well and enjoy a long life. Use

of masonry joint reinforcement and accessories is an essential part of this. This course provides a brief history of solid

masonry walls leading up to the modern cavity walls of today, including a discussion of the basic working knowledge of

masonry joint reinforcing, structural codes, and moisture control in cavity wall construction.

Learning Objectives:

At the end of this program, participants will be able to:

• describe the history of solid masonry walls and how they have shifted into today’s cavity walls to meet the evolving

needs of modern societies

• analyze the types of joint reinforcing including their design, function, correct application, and installation, as well as

their role in ensuring the safety and performance of masonry walls

• evaluate the types of adjustable ties and stone anchors available, including how to choose the proper type for a

specific project and proper installation techniques, and

• explain the types of flashing, mortar dropping collection devices, and weeps used in masonry walls and how these

devices deal with possible water intrusion to ensure the life of the masonry wall.






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Contents

A History of Masonry Walls

Developing the Masonry Structures Code

Joint Reinforcing for Single-Wythe Walls

Joint Reinforcing for Multi-Wythe Walls

Flashings, Mortar Dropping Collection

Devices, and Weeps

Click on title to view






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A History of Masonry Walls






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A Brief History of Masonry Walls

No one knows exactly when the first wall was built; perhaps cavemen and cavewomen felt they needed to protect

themselves from wind, rain, and various animals that might try to get into their caves. Stone or dry mud from a lakebed

would have been stacked to create some type of wall.

Although somewhat effective, these walls still required mud as a mortar to help support the stones or pieces of dry mud

from a lakebed as the wall grew in height.

As time went on, people found that the mud alone was not sufficient as the water evaporated from the mixture. The mud

would crack and fall out. In an effort to reinforce the mud/mortar, various grasses, weeds, and even horsehair were

added to the mix. This mix was also used as “chinking,” the reinforced material placed between the logs of a log cabin

that helps keep the wind, rain, and cold outside.






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Mesopotamia

6,000 years ago the Mesopotamians built the world’s first walled cities.

These walls used clay masonry units of special shapes and a running bond pattern. A running bond pattern is where the

next row of bricks is laid across the two ends of the bricks below. This pattern helped strengthen the wall from horizontal

wind loads and is still the most common pattern used today.

It should be noted that as the wall grew in height, the wall’s overall thickness also grew in an effort to carry the loads from

above.






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Pyramids of Giza

5,000 years ago the great pyramids were built

from large blocks of stone that were set using

white ground-up rock with water added as the

mortar.

This white rock was gypsum, which is still

utilized today as a fire-rated core for gypsum

board.






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Mud Brick

Eventually, builders decided that they needed a more uniform shape in creating their mud brick. So they created a wood

form in which they not only added the mud and local silt, but also helped reinforce the bricks by using weeds, grasses, or

even horsehair.

We still reinforce our masonry structures today with additives like chopped glass fiber, ceramic fiber, and wire welded

mesh in things like concrete slabs and sidewalks. These wood-formed and sun-baked masonry units are still done in some

areas around the world.






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Early Masonry Walls

The Monadnock Building in Chicago, Illinois

was completed in 1891. With its 17-story load-

bearing masonry walls, it was the tallest of

any commercial structure in the world. Walls

at the bottom of the structure were 6′ thick,

tapering to 18″ at the top of the building.

The architect used an interior frame of cast

and wrought iron to help the walls withstand

high wind loads. This was the first attempt at

wind bracing. This building is often referred to

as the “last masonry skyscraper.” Now all

high-rise buildings use structural steel backup

to help with lateral wind loads and minimize

weight.

Images: courtesy of The Chicago

Historical Society






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Wind-Driven Rain

One of the biggest problems with solid

masonry construction is how you might deal

with water migration through the material.

Wind and rain most often go hand in hand.

Wind can push the water through the

masonry and mortar used to set the units.

It should be noted that masonry does a

great job at absorbing and storing heat,

then slowly releasing that heat, keeping

heating, ventilating, and air conditioning

systems from working too hard.

Wind-driven rain caused a lot of problems

for early solid masonry walls.






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Early English Cavity Wall

In England in the late 1800s, solid masonry walls were still the norm.

However, the problems typically associated with this type of structure

were mildew and cold surfaces on the interior walls. In an effort to stop

moisture and thermal migration, a cavity was created between the two

wythes. Remember a wythe is a single unit of masonry. Special

elongated bricks were created to bond the two wythes together creating a

cavity. Their intent was to minimize the potential for a thermal break

between the two wythes and minimize the surface area where water

might push through to the interior wall.

This special bonding brick created a “masonry bond,” but this type of

bonding still created a moisture path and thermal bridge between the two

wythes. In an effort to address this problem, smaller wire ties were

created to tie the two wythes together. These metal ties had a much

smaller surface area reducing the thermal transfer. A bend, or “drip,” was

added to the wire tie so that if water tried to migrate across the wire tie

from the outside wall to the inner wythe, then it would drip down and be

“weeped” away through small holes at the base of the wall back outside.

This type of system was known as a “wire bond.”

Special bonding brick

used to bond two

wythes is called a

masonry bond.

Interior plaster finish

This masonry bond

created a moisture

path and a thermal

bridge. This masonry

bond soon became a

wire bond as metal

ties were developed.






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Brick Alternative

It has been found that these bends can reduce the strength of the tie

by as much as 50%. You will not find them in wire ties today. In the

late 1800s, a stronger alternative was created to replace the interior

brick wythe. In many instances, the exterior brick is considered a

curtain wall or brick veneer. The interior wythe is normally there to

carry the loads from above (wall, floor, roof, etc.). A single wythe of

brick was limited in its structural ability.

The first concrete masonry unit (CMU) was molded in 1882. Concrete

blocks create structures that are economical, energy efficient, and

fire-resistant, and involve minimal maintenance.

The first size was 7⅝″ wide x 7⅝″ high x 15⅝″ long; the same CMU

dimensions are used today. The standard mortar joints for a typical

CMU are ⅜″ thick. This brought the overall size of the CMU to 8″ x 8″

x 16″. A typical brick dimension is 3⅝″ wide x 2¼″ high x 7⅝″ long.

Therefore, three bricks high plus three mortar joints equal 8″, allowing

the brick to course out with the CMU.






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Concrete Exterior

Concrete blocks can be used as a finished exterior surface or as a structural backup wall for brick or stone veneers.

A CMU can also have a ceramic coating applied to the outside face. This is a good choice for some very dramatic effects

and it is easy to clean should graffiti become a problem.






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Today’s Block Backup Cavity Wall

All of this development has now led up to today’s block backup

cavity wall as you see in the image. Management of potential

water intrusion and loads, both vertical from material weight and

horizontal from wind loads, is now addressed in this modern

cavity wall.

After the slab or footing is poured, it is time to lay the CMU. The

structural engineer may have called for reinforcing steel bars or

rebar to be grouted into some of the CMU cells. Typically, one or

two pieces of rebar will be grouted solidly into the cell to help with

wind loading in the area. The rebar will normally be centered in

the cell so it can work equally with either positive or negative wind

loads. Rebar positioners are used about every 4′ vertically. As

you will see later in the course, some rebar positioners are better

than others.






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As the CMU is laid, masonry joint reinforcing is also laid every other course or 16″ on center vertically. Since 99% of the

projects specified call for ⅜″ mortar joints, it is important to remember that code dictates the masonry joint reinforcing no t

exceed half the thickness of the joint. Therefore, a ⅜″ mortar joint requires a 3/16″ maximum height for the masonry joint

reinforcing. This allows for better coverage of mortar around the masonry joint reinforcing. The masonry joint reinforcing

can be either 9 gauge (0.1483″) or 3/16″ diameter if more stringent loads are to be met.

Most CMU is 15⅝″ long with a center web. With a single ⅜″ mortared head joint, this brings the total length to 16″. If a

brick or stone veneer is to be used, then the tie will occur at 16″ on center at the center line or web of the CMU. This

brings the typical spacing for the ties to the exterior brick veneer to 16″ vertical and 16″ horizontal.

Code also states that any metal passing through the cavity of the wall shall be a minimum of 3/16″ in diameter. The cavity

is the distance from the back of the CMU to the back of the brick. Insulation and air space can take up some of this space,

but the cavity is still wythe to wythe.






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Masonry walls need movement joints to allow for either

expansion or contraction in the wall. As a rule, brick tends to

expand while CMU tends to contract. Since brick is exposed to

the elements, ⅜″ expansion joints made of closed cell

neoprene and allowing for a compression of 50% are normally

used. Sealant or caulking is used to cover and protect the

expansion joint from water and ultraviolet deterioration.

For CMU, a control joint is installed allowing for the CMU to

contract. The block manufacturers will form blocks with a

groove already set in the end of the block to receive the control

joint.

Typically, this product is made from PVC (polyvinyl chloride) or

rubber. Rubber control joints tend to perform better than PVC.

Notice the black control joint depicted on the end of the wall.






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Ties come in many forms, hook and eye being the most

common. Eyes are welded to the masonry joint reinforcing and

protrude out just far enough for the eye to clear the insulation.

Remember, since this eye has entered the cavity, it must be a

minimum 3/16″ in diameter by code.

To complete the reinforcing of the brick veneer wall or wythe, a

double hook is inserted into the eyes and is laid over onto the

brick. This hook should lie a minimum of 1½″ onto the brick. The

hook should be held back from the outside surface of the brick

wall about 1″.

Code states that the outside mortar coverage of the tie should

be a minimum of ⅝″. So, if you hold the tie back about 1″ and

compress or “tool” the mortar joint, you should then be code

compliant. Remember the spacing is typically 16″ o.c. vertical

and 16″ o.c. horizontal. These ties are now able to transfer the

positive and negative wind loads to the stronger CMU.






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Today’s Block Backup Cavity Wall: Moisture Management

Up to this point, we’ve dealt with structural items. Now let’s take a look at moisture management.

You will notice that the image on the previous slides shows a stainless steel drip edge flashing on the outside wall just

below the level of the interior finished floor. Weeps are installed down to the surface of the drip edge a minimum 24″ o.c.,

allowing any water to drain from the cavity. Additional weeps are sometimes installed to increase drainage and increase

airflow in the cavity. Airflow can be improved by adding weeps at the upper portion of the wall, allowing the air to circulate.

There are many types of weeps as you will see later. The design of the weep should allow good air movement, and a

screening capability to stop insect intrusion into the cavity.

Although not shown clearly on the next image, weather barriers are usually applied to the face of the CMU. These can be

sprayed, brushed, or rolled onto the wall prior to installing the flashing (seen in gray on image). If a sheet good is used

then it would lap over the gray flashing, creating a shingled effect. Shedding and directing water to the cavity and out of

the masonry wall system is as important as the wall’s structural capability.






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The use of a collection device is now the preferred method. Notice the blue material in the cavity. This material is made of

polypropylene. The strands are randomly woven together creating a product that is 90–95% air. This product comes in

various thicknesses to accommodate varying cavity dimensions. The product can be rectangular in shape or a dovetail

shape as indicated. The product catches the mortar droppings while allowing water to still pass through to the weeps. The

dovetail shape works well by keeping mortar away from the under portion of the dovetail.

Flashing is often made in a peel and stick configuration. The flashing itself is a composite

of a release paper, some type of glue base such as butyl adhesive, rubberized asphalt,

etc. and an outer layer of stainless steel, copper, polyester scrim, and others. Since it is

important for the flashing to remain in place on the side of the wall, a small, flat bar is

mechanically installed at the top edge of the flashing. A bead of caulk is applied to the top

edge of this termination bar.

As the exterior masonry veneer wall is being installed, the mason is expected to keep the

cavity clear of any mortar droppings that might block the weeps. The normal way to do

this is to take the trowel and flatten the excess mortar to the back of the wall. In the past,

a wooden stick with strings attached to each end was dropped into the cavity with the

expectations of drawing the stick up and bringing any mortar droppings along with it. This

seldom worked well and is typically not done today.






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Review Question

How many years ago

was the first walled city

built?






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Answer

How many years ago

was the first walled city

built?

6000 years ago in

Mesopotamia.






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Developing the Masonry Structures Code






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Masonry Reinforcing

What forces act upon a masonry wall? What environmental

impacts should be taken into account—wind, seismic, rain,

etc.?

Many things go into designing masonry walls. When dealing

with wind, it’s important to remember that wind can create a

compressive load on the brick as it blows against the wall. As

the wind whips around and over the building, tension loads

can act upon the wall and actually pull the brick or stone off

the wall. How these wythes in a wall work with the ties

holding them together is all part of the masonry structures

code.






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Seismic Concerns

Other concerns can come from seismic

conditions. As the ground shakes and moves in

an earthquake, the masonry ties need to

transfer the loads between the two wythes

accordingly.

The ties still need to keep the wall from

deforming or bending to the point that the

mortar joint cracks and lets in too much water

from wind-driven rain. Additional wire or rods

are added in the exterior brick wythe to give

added strength. You will see examples of this

later in the presentation.






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Code Requirements

To understand more about the design of masonry walls and their

code requirements, you might look to the information provided by a

number of associations. The Brick Industry Association (BIA) is a

great first search for technical information and details,

www.gobrick.com.

The International Masonry Institute is developing BIM-M (Building

Information Modeling for Masonry), a source for the industry to come

together and offer architects, designers, and contractors good

generic details for the masonry industry, www.imiweb.org.

The Masonry Society www.masonrysociety.org, American Concrete

Institute www.concrete.org, Structural Engineering Institute

www.asce.org/structural-engineering/structural-engineering-institute,

and Mason Contractors Association of America

www.masoncontractors.org are all excellent resources.




http://www.gobrick.com/

http://www.imiweb.org

http://www.masonrysociety.org/

http://www.concrete.org/

http://www.asce.org/structural-engineering/structural-engineering-institute

http://www.masoncontractors.org/



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Building Code Requirements and Specifications for Masonry

Structures

Through the work done by the various associations, a committee

was formed by three of them in 1989. This committee was made

up of representatives from the Masonry Society, the American

Concrete Institute, and the Structural Engineering Institute. This

group was known as the Masonry Standards Joint Committee

(MSJC).

The document they created is Building Code Requirements and

Specification for Masonry Structures (TMS 402-13/ACI 530-

13/ASCE 5-13). This document comprises code requirements,

specifications, and commentaries. (Since it was written by many

engineers, they broke it down into verbiage that us regular guys

can understand in the commentary section.) Going forward in this

presentation, you may see the codes referred to as “TMS 402” or

simply “code.” Sizing, material type, spacing, etc. is typically found

in this book.






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Joint Reinforcing for Single-Wythe Walls






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Truss Type Joint Reinforcing

Twenty years ago, truss type reinforcing was the norm when it

came to joint reinforcing. It comprises two elongated steel rods

and a welded diagonal rod, either 9 gauge or 3/16″ diameter.

The diagonals tended to get in the way of grout pours and

reinforcing bars that might be called for in the cells of the block.

In general, truss type reinforcing is too strong for cavity walls

but is still okay for single-wythe walls.

Masonry joint reinforcing and rebar is typically called out and

sized by the structural engineer.






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Ladder Type Joint Reinforcing

Ladder type reinforcing is now the preferred product for CMU

walls. It comprises two elongated rods and a cross rod (either 9

gauge or 3/16″ diameter) at 16″ on center.

The 16″ on center design positions cross rods on the center

web of the block to allow core clearance. This simplifies rebar

installation, allows unrestricted flow of grout or loose fill

insulation into CMU cells, and provides a stronger bond with

cross rods in the center web of the block.






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Ladder Corners and Tees

Truss or ladder corners and tees are available for all joint

reinforcement sizes. Typical lengths are 30″. Code dictates that

you should splice or overlap ends of reinforcement a minimum of

6″ with adjacent reinforcement.

In addition, the reinforcing should be kept back from the outside

face (weather side) about 1″ to allow for ⅝″ mortar coverage once

tooled.






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Functions of Joint Reinforcing

Joint reinforcing strengthens the mortar joint, which helps control shrinkage cracking. It bonds masonry wythes together in

composite and cavity walls. One-inch air space is required, but 2″ is recommended.

Joint reinforcing also allows loads to be transferred from the brick veneer to the stronger CMU or metal stud backup,

bonds intersecting walls, and increases the wall’s flexural strength.






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Wire Sizes and Finish Descriptions for Ladder and Truss Reinforcing

Wire Gauges Side Rods Cross RodsStandard 9 ga. 9 ga.

Heavy duty 3/16″ 9 ga.

Extra heavy duty 3/16″ 3/16″

Finish DescriptionMill galvanized Zinc coated (.10 oz/ft); used for interior masonry walls only.

Hot-dipped after fabrication 15x more zinc than mill galvanized (1.5 oz/sq ft), minimum required for exterior

walls.

Stainless steel Type 304 stainless is the best product for high humidity and caustic environments.






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Reinforcing Wire Deformations

ASTM A951—Standard Specification

for Steel Wire for Masonry Joint

Reinforcement.

Longitudinal wires shall be deformed.

One set of two deformations around

the wire shall occur at not less than

eight sets per inch. This helps with

the adhesion of mortar to the wire.






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Joint Reinforcing Installation

Lay reinforcing on the wall in advance of the mortar. Apply

mortar to bed joint. Since wire is round and not flat, mortar will

surround the reinforcing and no lifting is required.

Position side rods allowing a minimum of ⅝″ coverage between

the reinforcement and the exterior face of mortar.

When using ladder type, always keep the cross rods in the web

of the CMU.

To meet requirements of TMS 402/ACI 530 code, the ends of

the ladder must overlap creating a splice of at least 6″. To

ensure bonding in the bed joint, the height and thickness of the

reinforcement shall not exceed half the thickness of the mortar

joint. Three-eighths of an inch mortar joint equals 3/16″

maximum reinforcement height.






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Review Question

What functions does joint

reinforcing play in single-

wythe walls?






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Answer

What functions does joint reinforcing

play in single-wythe walls?

1. Joint reinforcing strengthens the

mortar joint, which helps control

shrinkage cracking.

2. It bonds masonry wythes together in

composite and cavity walls.

3. It allows loads to be transferred

from the brick veneer to the stronger

CMU or metal stud backup, bonds

intersecting walls, and increases the

wall’s flexural strength.






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Joint Reinforcing for Multi-Wythe Walls






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Ladder Three-Wire, Four-Wire, and Fixed Tab

Ideally, the types of reinforcement shown (ladder three-

wire, four-wire, and fixed tab) work best when the brick

and the block course out evenly.

On jobsites it is typical for the CMU to be installed first,

since it is the load-bearing portion of the wall. It is the

part of the wall that carries the weight of the wall,

floors, and roof above. This allows for the project to

proceed more quickly. Later as the brick or stone

veneer is installed, the mason will typically bend the

reinforcing out of the way that is hanging out of the

block every 16″ on center vertically. The mason then

tries to bend the reinforcing back down to the top of the

brick or stone veneer. This simply doesn’t work. This is

where adjustable ties came into play and are now the

norm.






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Level Ladder Hook and Eye

As stated earlier, the level ladder hook

and eye is probably the most common

adjustable tie for CMU backup on the

market. Several things are required by

code for all masonry ties.

1. Any reinforcing steel used to tie the

veneer brick or stone back to the

stronger backup wall that crosses the

cavity shall be a minimum of 3/16″ in

diameter.

Hook design

allows for 1¼″

vertical

adjustment.

Double eyes welded level to ladder

at 16″ o.c., maintaining 3/16″ max

wire height in ⅜″ mortar joint.

Max 1/16″ tolerance where hook

intersects eye as per code.

Legs of hook

hold 16″ high

insulation in

place during

construction.






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Level Ladder Hook and Eye

2. Since the brick or stone veneer is typically laid sometime after the CMU, the tie will have an adjustment of at least 1¼″

vertically to accommodate potential uneven coursing between the two wythes. At the end of the 1¼″, the tie should

have a bend or loop to discourage disengagement.

3. Where the 3/16″ diameter tie interacts with the 3/16″ diameter loops or pintle coming from the stronger backup wall,

no more than a 1/16″ tolerance is allowed. This minimizes excessive movement as the wind changes from a push/pull

load.

4. The hook should lie at least 1½″ onto the brick from the cavity side and have at least ⅝″ mortar coverage from the

weather side.

5. As per the Brick Industry Association, each tie should be able to withstand a minimum 100 lb load in either tension or

compression.






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New Energy Codes = More Insulation

The new International Energy Conservation Code

(IECC) went into effect across the US in January

2015. This code requires better R-values than

previously required. Architects are specifying thicker

insulation to meet these requirements. Where total

space between the back of the brick to the face of

the block might have been 3½″–4½″, it is now being

extended to 6″ or better.

IECC: International Energy Conservation Code & ASHRAE 90.1-2013






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Reinforcing Size

It is important that the architect, dealer, or contractor

convey these four dimensions so the manufacturer

can supply the correct products for the job. The

manufacturer will know which products, sizes, and

material will work best and meet the codes.

The manufacturer needs four dimensions:

1. Block size (6″, 8″, etc.)

2. Insulation thickness

3. Air space

4. Brick size (4″, etc.)






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Need Something Stronger?

Tornados, hurricanes, and safe rooms might require

even more strength from the adjustable ties, keeping the

brick on the wall and not on your head.

Manufacturers are making various types of pintles that

began their life as hooks. The leg has been extended

and looped back on itself, making the pintle virtually

impossible to disengage.

Code requires ties to be 3/16″ wire and to be adjustable

a minimum of 1¼″ should the brick not course out

evenly.

They are installed at 16″ vertically and 16″ horizontally.

3/16″ dia. Tab

with Lock bar

3/16″ dia.

Locking Pintle






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Stronger Hooks

Stronger hooks are great for wider cavities,

thicker insulation, and higher wind loads. As

mentioned in the previous image, stronger ties

might be required in very high wind loads.

About one-third of the country now requires

schools and some public spaces provide a

safe room where all students and teachers

can gather in an emergency.

These rooms need to be able to withstand an

EF-3 tornado. If the contractor is already

accustomed to using hook and eye, why not

simply increase the tensile strength of the

steel, thus increasing the overall performance

of the tie by as much as 2½ times.

The hook maintains a 3/16″ diameter

allowing it to be used with the standard

level eye products. Remember that

whatever the material used to

manufacture the hook, the same

material should be used on the eyes.

Hooks fabricated from high tensile

strength spring wire are simple, yet over

2 times stronger than standard hooks.






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Cavity Walls With Steel Stud Backup

When it comes to the walls that back up masonry and stone

veneers, steel stud walls are more common than CMU. Most

of the components are the same as CMU backup with the

exceptions of the masonry joint reinforcement and the types of

ties.

Since there is no CMU, the masonry joint reinforcement will

not exist. The ties, as opposed to being hooked to the sides of

something welded to the side of the joint reinforcement, are

now attached through the insulation and/or sheathing back to

the metal stud.

You might also notice on this image that a butyl tape is used

all the way up the wall at the tie locations. This acts as a

gasket material around the screw at the tie.

• Strong

• Economical

• Energy efficient

• Low-maintenance

• Built to last






< >

Various Types of Adjustable Ties for Steel Stud Backup

Post Type w/ Triangle Plate w/ Hook Type lll w/ Triangle

Plate w/ Triangle Plate w/ Hook Type lll-X w/ Triangle

Since there are only two or three manufacturers of adjustable metal ties in the country, it is sometimes difficult to have a

generic term that describes the tie. The images you see show six typical adjustable ties from the masonry industry for

steel stud backup.






< >

Various Types of Adjustable Ties for Steel Stud Backup

As shown on the previous slide, the top left image is a “post type” tie that works for all types of backup walls, which we wi ll

discuss in more detail later.

The top center is a “plate with hook” that requires at least two fasteners. This plate should be installed on the face of the

gypsum or plywood sheathing and weather barrier if one exists. The prongs on the plate will extend to just beyond the

insulation so that the hook can be inserted. There are three holes in the plate and we would like to see one of the two

anchors in the center hole. The center hole is more in line with the hook when in tension and better distributes the load.

The top right is a “type III with triangle.” This tie offers a lot of vertical movement. It is acceptable to be placed over a ll

types of substrates, but not over insulation. Two fasteners are required.

The bottom left is a “plate with triangle tie” that would work at the ends of rigid insulation or possibly with sprayed-on

insulation.

The bottom center and bottom right are similar to the ties above them on the previous slide. The difference is that they

now include teeth or prongs designed to be driven through the sheathing and/or insulation. The teeth are expected to hit

the stud beyond. These products require the contractor to hit the center of the stud, which crushes the sheathing or

insulation in the process.






< >

Adjustable Anchor and Tie Requirements

Anchors that connect the veneer to the backing must provide out-of-plane support, resisting tension and compression, but

allowing shear. Anchors must be embedded at least 1½″ into the brick veneer with a minimum mortar coverage of ⅝″ on

the outside face of the wall.

Maximum clearance between connecting parts of the tie shall be 1/16″. Adjustable anchors shall be detailed to prevent

disengagement. Pintles (double hooks) shall have at least two 3/16″ legs and shall have an offset not exceeding 1¼″.

Horizontal and vertical spacing shall not exceed 16″ o.c. Wall ties shall be without drips. Minimum air space shall be 1″ per

code, but 2″ is recommended by all industry associations.

Maximum void between steel framing and inside face of veneer is 6 ⅝″ by code, without any engineering or tie

calculations.

Maximum span for a wire tie in the cavity is 2″ when the cavity exceeds 4 ⅝″.






< >

Plate with Hook and Type lll Anchoring Systems

Plate w/ Hook Type lll w/ Triangle

Two holes above legs helps with

installation when insulation used.

Hook allows 1¼″ up and down

movement.

Rubberized tape creates a seal

where screws penetrate.






< >

Post Type Anchoring System

As mentioned earlier, we are now going to discuss a post type

anchoring system. This type of tie is really growing in

popularity. It is installed in any type of substrate. In CMU and

concrete, a pilot hole is drilled to 3/16″. Then a ¼″ masonry

screw with a special head is driven into the wall. It can go

through insulation or sheathing. Since there is a rubber

washer already attached to the specialized screw head, no

butyl tape is required.

This type of post anchor creates only one hole instead of two.

The screw comes in two types of finish. The thermoset

polyester finish is used for concrete, CMU, and wood. An anti-

corrosion finish with a cutting tip is available for steel studs. A

self-drilling tip means no pilot holes. All screws come in

various lengths to accommodate varying insulation

thicknesses. A special chuck is available to fit in any drill for

easy installation.

A masonry

screw allows

positive contact

with wood and

concrete.

A screw with

anti-corrosion

finish

accommodates

sheathing and

various

thicknesses of

insulation.

A specially designed chuck allows the

post type anchor’s slotted head to

easily slip in with a straight and snug

fit.






< >

Post with Triangle Anchoring System

As seen in the image, a 3/16″ diameter triangle is attached

when it is time to lay the exterior masonry. Notice the design

of the triangle allows for 1¼″ vertical movement and only a

maximum 1/16″ back and forth movement where the triangle

connects to the screw as per code.

All three of the tie manufacturers produce a similar product.

These ties work with all substrates and keep it simple for the

architect and masonry contractor.Only one hole

penetrates the

wall instead of

two.






< >

Post with Triangle Anchoring System

Note that ties in masonry walls are considered by three sources to add no appreciable thermal conductance.

1. When the new International Energy Conservation Code (IECC) was adopted 1/1/2015, it stated, “the code does not

require a reduction in R-value calculation for masonry ties, fasteners, or anchors.”

2. The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) in their report, “Thermal

Performance of Building Envelope Details for Mid- and High-Rise Buildings” (5085243.01 MH 1365-RP July 6, 2011)

states that brick ties are an example of a clear field anomaly and “are considered not practical to account for on an

individual basis for whole building calculations.”

3. In August 2015, Architectural Testing, Inc. constructed two 8′ x 8′ brick veneer walls, one with ties and one with no ties

to gauge the thermal conductance of the ties. The walls were ½″ drywall, 16 gauge 2 x 6 metal studs, 16″ on center,

5/8″ gypsum sheathing, 2″ rigid insulation board, 1″ nominal air space, masonry ties at 16″ on center both vertically and

horizontal, 4″ nominal common red brick. In conclusion, “The wall assemblies, as tested, performed identically in terms

of U-Factor and R-Value” and “fasteners do not create any significant thermal bridging effects on this wall system.”






< >

Rebar Positioners

When rebar is grouted into cells of CMU, it

is important to locate the reinforcing where

the structural engineer intended. Usually it

is in the center of the cell since the wind

loading can put the wall in either tension or

compression.

Since these rebar positioners are laid in wet

mortar, movement is typical from the weight

of the rebar. They should be placed about

every 4′ vertically.






< >

Recessed Rebar Positioner

A better solution for holding the rebar in place

is a recessed rebar positioner. This type of

rebar positioner is rigidly held in place by the

CMU and is not dependent on the wet mortar,

ensuring that you keep the rebar where the

structural engineer wants it. All rebar

positioners are available for both single and

double reinforcing bars plus the splice.

Installs 1¼″ deep instead of on top

of the block.

Does not interfere with ladder wire

reinforcement.

Design prevents any movement

during installation.

Code requires that rebar be kept in

center of block cell.






< >

Stone Anchors

Stone is another type of veneer that still needs to be anchored

back to the substrate. Typically, when laying irregularly

shaped stone, a pencil rod system might be used. This allows

triangles to move vertically up the rod and be laid randomly in

the mortar joints as the stone shape might require.

Tabs are welded to the truss or ladder type joint reinforcing

and a 3/16″, ¼″, or ⅜″ diameter “pencil rod” is slid through the

tab vertically. Next a 3/16″ diameter lock bar triangle or

dovetail triangle is slid onto the pencil rod. Components are

either hot-dipped galvanized or stainless steel.






< >

Stone Anchors

When the stone veneer is cut even with square edges, a

slot or hole is cut or drilled into the edge of the stone.

The manufacturer will usually determine how many

anchors they might need per stone piece. These

anchors are normally ⅛″–½″ thick stainless steel. In

situations where holes are drilled into the edge of the

stone, anchors with a dowel might be provided.

These types of anchors, either slot or dowel, are usually

rigidly attached back to the substrate. Fasteners used to

attach the anchors to the substrate will vary. They can

be attached with expansion bolts when tied back to

masonry.






< >

Review Question

Match the images on the

right with the correct label

on the left.

Ladder three-wire

Four-wire

Fixed tab






< >

Answer

Match the images on the

right with the correct label

on the left.

Ladder three-wire

Four-wire

Fixed tab






< >

Flashings, Mortar Dropping Collection Devices, and Weeps






< >

Basic Types of Flashing

As you have seen with some of the

developments of masonry walls, other

than improving the structural capabilities,

dealing with the possible water intrusion

into and through the wall is just as

important. Just as shingles on the roof

are designed to shed water off and away,

the same applies to flashing in a masonry

wall.

Flashing details associated with masonry

walls can be found through the Brick

Industry Association and the International

Masonry Institute. In this presentation we

will deal with some of the basic types and

where they might be used.

Flashing termination

bar caulked along

top edge.

Drip edge flashing made from 304 stainless steel.

Flashing comes in a

wide variety of materials.

Trowel applied mastics,

polyethylene and

rubberized asphalt

composites, peel & stick,

copper fabrics, etc.






< >

Types of Flashing

PVC: Non-reinforced polyvinyl chloride sheet:

Use in milder climates because it can become rigid and brittle under severe freeze-thaw conditions.

Use on concealed foundation walls, under slab, and as thru-wall flashing.

Polyethylene/Rubberized Asphalt:

Can be used in all climates, is peel and stick. Sticks to concrete, steel, wood, and gypsum.

Use for thru-wall, foundation sill, base, parapet head and sill.

Polyester Scrim/Thermoplastic:

Many companies use a thermoplastic product, a ketone ethylene ester (KEE). Used with a polyester scrim and butyl

adhesive, it works very well.

For use in all climates, is peel and stick. Resists oil and most chemicals, will not drool, no UV degradation, and is

considered the best non-metallic peel and stick.






< >

Types of Flashing

Copper Fabric: Copper sheet laminated between blended asphalt and glass fabric:

3, 5, and 7 oz copper. Excellent for thru-wall and surface applications with no drool.

Copper/Rubberized Asphalt:

3 oz copper sheet with polyester film on one side and rubberized asphalt on the other. It is highly adhesive. Rubberized

asphalt has a greater longevity compared to standard asphalt.

Please remember the test password FLASHING. You will be required to enter it in order to proceed with the online test.






< >

Mortar Droppings Collection Device and Weeps (MDCD)

The basic idea is to allow any water that might get through the exterior veneer to be stopped by the flashing, fall, or run

down the cavity and be weeped out of the cavity through weeps at 24″ on center horizontally. In general, the MDCD

should be in the bottom of the cavity to catch any mortar that might fall into the cavity while the exterior brick wall is laid.

The MDCD keeps the weeps clear. Weeps can come in many types. When selecting weeps, consider the following.

1. Weeps should allow water to exit the cavity.

2. Weeps should stop insects from entering the cavity from outside.

3. Recently there has been a push by the design community to add more weeps in an effort to increase the airflow or

convection of air in the cavity. Weeps or Vents should be spaced 24″ horizontally to meet code requirements. Adding

weeps under windows and at the tops of walls is also a good idea.

4. Select weeps that offer more airflow by their design.

5. Selecting weeps that more closely match the mortar color is usually a good idea for aesthetic reasons.






< >

Mortar Droppings Collection Device (MDCD)

This MDCD is made of a polymer core composed of high-density polyethylene strands woven into a thick mesh. The

product is 90–95% air. Thickness varies based on the cavity width. Keeping the MDCD slightly narrower than the cavity

helps prevent any possible bridging of mortar across the cavity. A better design is the dovetail shape. The dovetail creates

an overhang preventing mortar from building below.






< >

Clear Round Weepholes

They are available with

a filter and a wick. This

type of weep circulates

little air, or none with a

wick.

Install a minimum 24″ on center as per code.






< >

Clear Rectangular Vent

They are available with

a filter and a wick.

Install 24″ on center as per code.






< >

Cavity Net Weep

Made similarly to the MDCD material shown in blue, this weep

solves many issues:

1. Fits firmly in brick head joint

2. Is 90–95% air (great airflow)

3. Stops insects from entering cavity

4. Is available in various colors from many manufacturers






< >

Cell Vent

The cell vent is an ultraviolet resistant

polypropylene co-polymer that allows

for good airflow and stops insects. It is

available in many colors.






< >

Conclusion

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