Masonry

Question 1

what does CMU stand for

Answer 1

Concrete Masonry Unit

Question 2

what is the weight of a CMU

Answer 2

35-45 lbs

Question 3

what are the nominal and actual dimensions of a CMU

Answer 3

nominal dimensions: 8” x 8” x 16”

actual dimensions: 7 5/8 “ x 7 5/8 “ x 15 5/8 “”

Question 4

what is the weight of cinder blocks

Answer 4

25-35 lbs

Question 5

what are some desirable properties of mortar

Answer 5

• plasticity
• water retentivity
• strength and durability

Question 6

which cement already contains masonry lime

Answer 6

masonry cement contains masonry lime

portland cement you have to add it

Question 7

what are the types of mortar

Answer 7

• type m
• type s
• type n
• type o

Question 8

when hand mixing mortar what material do you place first

Answer 8

place the sand first then mix all dry materials before adding water

Question 9

what is the mixing time for mortar when using a machine

Answer 9

3-5 min

first place most of the water then half of the sand, then cement and rest of the sand

Question 10

what are the two types of sand

Answer 10

manufactured and natural

Question 11

true or false

calcium chloride should not be used for steel re-inforced masonry

Answer 11

true

Question 12

what is calcium chloride

Answer 12

can be used as an accelerator

Question 13

what two mortar materials should not be stored in a dry place

Answer 13

lime and sand

they should be covered to prevent moisture loss

Question 14

what are the parts of a masonry wall

Answer 14

• corners/end
• field
• control/expansion joints
• wall intersections
• rough openings

Question 15

when laying the corners how many courses high should they be

Answer 15

4 to 5 courses high

step each course back one half block

Question 16

when “checking the rack” what angle should the block courses be

Answer 16

45 degrees

Question 17

when laying the closure block, how much gap should be left

Answer 17

16 1/2 “ gap

Question 18

when placing anchor bolts, how far apart should they be

Answer 18

12” from the corners, the no more than 4’ apart after that

Question 19

what is the rule of thumb when placing control/expansion joints in masonry walls

Answer 19

no more than 25’ between joints, not more than 1/2” mortar

Question 20

what is modular coordination

Answer 20

when the design of a building, it’s components, and the building material units all conformto a dimensional standard based on our modular system

Question 21

what is modular measure

Answer 21

the system of dimensional standards for buildings and building components that permit field assembly without cutting

Question 22

what does planning save

Answer 22

• considerable labor
• time
• materials

Question 23

what are lintels

Answer 23

lintels are used to support masonry block over modular openings such as doors and windows in walls

Question 24

what are sills

Answer 24

sills are used to create a finished look for the bottom of openings in walls. they are usaually precast and installed following wall construction

Question 25

when do you tool/strike mortar joints

Answer 25

when they become “fingerprint” hard

Question 26

which joints do you strike first

Answer 26

vertical then horizontal