MNM Exam 2- Masonry Wall
Construction Questions and Answers
Are composite masonry walls loadbearing or non-loadbearing? - ANSWER-they can be
either!
Are masonry walls porous or non-porous? - ANSWER-every masonry wall is porous to
some degree
Can masonry span long horizontal differences (floor/roof)? - ANSWER-No- Masonry is
largely unable to span long horizontal differences (floors + roofs).
-Often combined with another horizontal system to create a hybrid structure system.
How are interior flashings installed? - ANSWER--Interior flashings are installed by
masons as they construct the wall.
How can efflorescence be avoided? - ANSWER--Choosing masonry units that do not
contain water-soluble salts
-Using clean ingredients in the mortar
-Minimizing water intrusion into the masonry construction
How can you insulate masonry walls? - ANSWER--on the outside face
-within the wall
-on the inside face
How can you prevent masonry from expanding/contracting too much? - ANSWER-Must
provide surface divider joints to avoid an excessive buildup of forces that could crack or
spall the masonry.
How does base flashing and counterflashing work together? - ANSWER--External
flashing at intersection of flat roof and wall parapet is usually constructed in two
overlapping parts:
-Base flashing - often formed by the roof membrane itself. It is normally turned up for a
height of at least 8 inches vertically.
-Counterflashing or Cap Flashing - embedded in the masonry wall above the base
flashing and extends downward, lapping over the base flashing
How does heavy timber construction and masonry construction work together? -
ANSWER-Hybrid System (Filigree + Solid)
-Uses heavy timbers rather than light joists, rafters, and studs.
-Uses thick timber decking rather than thin wood panel sheathing and subflooring.
-since heavy timber is slower to catch on fire/burn, larger floor areas and greater
building heights are permitted
, How does insulating on the inside face of masonry walls work? - ANSWER--Can be
insulated by attaching wood or metal furring strips to the inside of the wall.
-Furring strips may be of any desired depth to house the necessary thickness of fibrous
or foam insulation between the furring strips.
-Gypsum wallboard or other interior finish material is then fastened to the furring strips.
-Furring also creates spaces in which electrical wiring and plumbing can easily be
concealed. ▫
How does insulating on the outside face of masonry walls work? - ANSWER--Usually
accomplished by means of an exterior insulation and finish system (EIFS), which
consists of panels of plastic foam that are attached to the masonry and covered with a
thin, continuous layer of polymeric stucco reinforced with glass fiber mesh.
-Appearance is that of a stucco building.
-Masonry is completely concealed and can be of inexpensive materials and/or unrefined
workmanship.
-Thin coatings are not very resistant to damage, and can allow substantial moisture
leakage into the walls of the building.
How does insulating within the masonry walls work? - ANSWER--If cavity is wide
enough, masons can insert slabs of plastic foam insulation against the inside wythe of
masonry as the wall is built.
-Hollow cores of a concrete block wall can be filled with loose granular insulation or with
special molded-to-fit liners of foam plastic.
-Insulating the cores of concrete blocks does not retard passage of heat through the
webs of the blocks, however, and is most effective if coupled with a continuous,
unbroken layer of insulation in the cavity or on one face of the wall. ▫
How does the expansion/contraction of masonry compare to wood/plastic/aluminum? -
ANSWER-Expansion and shrinkage in masonry materials are small compared to the
moisture movement in wood or the thermal movement in plastics or aluminum.
How does water escape after it penetrates through the outer wythe? - ANSWER-it is
conducted down the cavity and out at the bottom of the wall by flashing and drained
through weep holes to the exterior of the building
How does wood joist construction and masonry construction work together? -
ANSWER-Hybrid System (Filigree + Solid)
-Floors and roofs are framed with light wood joists and rafters and supported at the
perimeter on masonry walls.
-Essentially balloon framing where outer walls of wood are replaced with masonry
bearing walls.
How far should a drip be placed in relationship with the outside face of the wall? -
ANSWER--the flashing should be carried at least ¾ inch beyond the face of the wall and
turned down at a 45-degree angle to create the drip
Construction Questions and Answers
Are composite masonry walls loadbearing or non-loadbearing? - ANSWER-they can be
either!
Are masonry walls porous or non-porous? - ANSWER-every masonry wall is porous to
some degree
Can masonry span long horizontal differences (floor/roof)? - ANSWER-No- Masonry is
largely unable to span long horizontal differences (floors + roofs).
-Often combined with another horizontal system to create a hybrid structure system.
How are interior flashings installed? - ANSWER--Interior flashings are installed by
masons as they construct the wall.
How can efflorescence be avoided? - ANSWER--Choosing masonry units that do not
contain water-soluble salts
-Using clean ingredients in the mortar
-Minimizing water intrusion into the masonry construction
How can you insulate masonry walls? - ANSWER--on the outside face
-within the wall
-on the inside face
How can you prevent masonry from expanding/contracting too much? - ANSWER-Must
provide surface divider joints to avoid an excessive buildup of forces that could crack or
spall the masonry.
How does base flashing and counterflashing work together? - ANSWER--External
flashing at intersection of flat roof and wall parapet is usually constructed in two
overlapping parts:
-Base flashing - often formed by the roof membrane itself. It is normally turned up for a
height of at least 8 inches vertically.
-Counterflashing or Cap Flashing - embedded in the masonry wall above the base
flashing and extends downward, lapping over the base flashing
How does heavy timber construction and masonry construction work together? -
ANSWER-Hybrid System (Filigree + Solid)
-Uses heavy timbers rather than light joists, rafters, and studs.
-Uses thick timber decking rather than thin wood panel sheathing and subflooring.
-since heavy timber is slower to catch on fire/burn, larger floor areas and greater
building heights are permitted
, How does insulating on the inside face of masonry walls work? - ANSWER--Can be
insulated by attaching wood or metal furring strips to the inside of the wall.
-Furring strips may be of any desired depth to house the necessary thickness of fibrous
or foam insulation between the furring strips.
-Gypsum wallboard or other interior finish material is then fastened to the furring strips.
-Furring also creates spaces in which electrical wiring and plumbing can easily be
concealed. ▫
How does insulating on the outside face of masonry walls work? - ANSWER--Usually
accomplished by means of an exterior insulation and finish system (EIFS), which
consists of panels of plastic foam that are attached to the masonry and covered with a
thin, continuous layer of polymeric stucco reinforced with glass fiber mesh.
-Appearance is that of a stucco building.
-Masonry is completely concealed and can be of inexpensive materials and/or unrefined
workmanship.
-Thin coatings are not very resistant to damage, and can allow substantial moisture
leakage into the walls of the building.
How does insulating within the masonry walls work? - ANSWER--If cavity is wide
enough, masons can insert slabs of plastic foam insulation against the inside wythe of
masonry as the wall is built.
-Hollow cores of a concrete block wall can be filled with loose granular insulation or with
special molded-to-fit liners of foam plastic.
-Insulating the cores of concrete blocks does not retard passage of heat through the
webs of the blocks, however, and is most effective if coupled with a continuous,
unbroken layer of insulation in the cavity or on one face of the wall. ▫
How does the expansion/contraction of masonry compare to wood/plastic/aluminum? -
ANSWER-Expansion and shrinkage in masonry materials are small compared to the
moisture movement in wood or the thermal movement in plastics or aluminum.
How does water escape after it penetrates through the outer wythe? - ANSWER-it is
conducted down the cavity and out at the bottom of the wall by flashing and drained
through weep holes to the exterior of the building
How does wood joist construction and masonry construction work together? -
ANSWER-Hybrid System (Filigree + Solid)
-Floors and roofs are framed with light wood joists and rafters and supported at the
perimeter on masonry walls.
-Essentially balloon framing where outer walls of wood are replaced with masonry
bearing walls.
How far should a drip be placed in relationship with the outside face of the wall? -
ANSWER--the flashing should be carried at least ¾ inch beyond the face of the wall and
turned down at a 45-degree angle to create the drip
