Ch. 37 - Masonry

Question 1

What do construction joints in masonry do?

Answer 1

Isolate the masonry from the through wall elements such as doors and windows.

Question 2

Control joints in masonry accommodate _______ and ______.

Answer 2

Thermal expansion and contraction.

Question 3

The slope of coping on top of a brick wall is called…

Answer 3

wash

Question 4

What is efflorescence?

Answer 4

A white, crystalline deposit from water-soluble salts on the surface of brick. It is caused when water seeps into the masonry and then evaporates leaving behind salts.

Question 5

What is the equivalent block thickness of an 8” thick concrete block that is 60% solids?

Answer 5

Actual thickness is 7 5/8” (7.625)

(7.625)(.60) = 4.58

Question 6

Major Expansion joints are placed every ________ to ________ feet in large buildings?

Answer 6

100’ to 150’

Question 7

Expansion and control joints are placed where in brick masonry walls?

Answer 7

Every 20’ and wherever a wall changes direction height of thickness

Question 8

Horizontal expansion joints should be placed where?

Answer 8

below shelf angles that support the intermediate sections of brick below beams and slabs of brick

Question 9

With Single wythe walls what is the maximum ratio of unsupported height or length to thickness cannot exceed?

Answer 9

20: 1 in solid masonry walls
18: 1 in hollow masonry

Question 10

What is the spacing of horizontal reinforcement in both CMU and brick masonry walls?

Answer 10

16” on center

Question 11

what are the 8 types of tooling in masonry construction?

Answer 11

concave, vee, flush, trowel struck, extruded, beaded, raked, weather struck

Question 12

What is the slope of the coping called?

Answer 12

The wash

Question 13

What is the typical spacing for weep holes?

Answer 13

24” on center

Question 14

What type of cement would be best when tuck pointing a masonry wall?

Answer 14

High lime cement

Question 15

What is mortar made of?

Answer 15

Portland Cement, hydrated lime, and an inert aggregate (sand)

Question 16

What type of mortar would be best in an exterior load bearing application?

Answer 16

Type M and S

Question 17

After what amount of time should masonry that was mixed be discarded?

Answer 17

2.5 Hours after it was mixed, because at this point the masonry has begun the chemical process

Question 18

What are the three grades of building brick?

Answer 18

SW (Oregon and Eastern coast of US)
MW (Midwest most of Washington)
NW (Southern US, New Mexico Oklahoma Texas)

Question 19

What are the three grades of facing brick

Answer 19

FBX- Best
FBS- Middle
FBA- Lowest

Question 20

What are the average thickness for mortar joints?

Answer 20

1/4”-1/2”

Question 21

How long after masonry is placed should the wall be struck?

Answer 21

1-2 hours

Question 22

What are the 4 types of masonry joints that are good in exterior applications?

Answer 22

Weathered Joint
Concave Joint
Vee Joint
Flush Joint

Question 23

What is the ideal temperature range for laying brick?

Answer 23

40 degrees - 90 degrees

Question 24

T/F Brick should be wetted before setting to minimize water absorption.

Answer 24

True

Question 25

Why is aluminum not used in flashing applications?

Answer 25

Because the chemical reaction that occurs between mortar and aluminum can disintegrate.

Question 26

What is the minimum clear airspace for a masonry wall?

Answer 26

2” while sometimes less with a rainscreen