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Masonry Details
Home Builder’s Guide to Coastal Construction
FEMA 499/June 2005
Technical Fact Sheet No. 16

Purpose: To highlight several important details for masonry construction in
coastal areas.

Key Issues
--Continuous, properly connected load paths are essential because of the higher
vertical and lateral loads on coastal structures.
--Building materials must be durable enough to withstand the coastal
environment.
--Masonry reinforcement requirements are more stringent in coastal areas.

Load Paths
A properly connected load path from roof to foundation is crucial in coastal
areas (see Fact Sheets Nos. 10 and 17). The following details show important
connections for a typical masonry home.

Durability – High winds and salt-laden air can damage masonry construction. The
entry of moisture into large cracks can lead to corrosion of the reinforcement
and subsequent cracking and spalling. Moisture resistance is highly dependent on
the materials and quality of construction.

Quality depends on:
--Proper storage of material – Keep stored materials covered and off the ground.
--Proper batching – Mortar and grout must be properly batched to yield the
required strength.
--Good workmanship – Head and bed joints must be well mortared and well tooled.
Concave joints and V-joints provide the best moisture protection (see detail
above). All block walls should be laid with full mortar coverage on horizontal
and vertical face shells. Block should be laid using a “double butter” technique
for spreading mortar head joints. This practice provides for mortar-to-mortar
contact as two blocks are laid together in the wall and prevents hairline
cracking in the head joint.
--Protection of work in progress – Keep work in progress protected from rain.
During inclement weather, the tops of unfinished walls should be covered at the
end of the workday. The cover should extend 2 feet down both sides of the
masonry and be securely held in place. Immediately after the completion of the
walls, the wall cap should be installed to prevent excessive amounts of water
from directly entering the masonry.

Reinforcement: Masonry must be reinforced according to the building plans.
Coastal homes will typically require more reinforcing than inland homes. The
following figure shows typical reinforcement requirements for a coastal home.

Gable Ends: Because of their exposure, gable ends are more prone to damage than
are hipped roofs unless the joint in conventional construction at the top of the
endwall and the bottom of the gable is laterally supported for both inward and
outward forces. The figure at right shows a construction method that uses
continuous masonry from the floor to the roof diaphragm with a raked cast-in-
place concrete bond beam or a cut masonry bond beam.