Heritage Building
Products supply Besser
Masonry(concrete) blocks. Besser Concrete masonry is
manufactured in accordance with the Provisions of Australian
Standard AS 2733-1984 “Concrete Masonry Units”. It is recommended
that design, drawing practice and construction be carried out in
accordance with AS 3700 – Masonry Code.
Modular Planning
The dimensions of masonry units are based on
the 100mm module. The actual size of units given are, in all
cases, 10mm smaller than their nominal sizes to allow for joint
thickness. For example, a block having an actual length of 390mm
will be classified as having a nominal length of 400mm. Estimating
data, including tables of wall length and wall height, are
available from Heritage Building Products.
Block Laying
Dry units are essential. Blocks should never
be wetted prior to application of mortar. Blocks should be kept
dry when stored on site before use. Whenever work is stopped, the
tops of walls should be covered to prevent moisture entering the
cores of the blocks. Blocks should be laid with the thickest shell
uppermost. Care should be taken not to allow mortar to drop into
cores if core is to be grouted.
Jointing
The mortar squeezed from the joints should be struck off flush
with the wall as each block is laid. When the mortar has stiffened
and is firm to the touch, it should be firmly compacted with a
jointing tool. This compactness is important since mortar, when
hardening, has a tendency to shrink slightly.
Control
Joints When required, the joints
should be located:
Wall Ties
Wall ties for cavity walls should be provided in accordance with
AS 3700.
Bond Beams
A bond beam is a continuous beam around the
exterior of a building for the purpose of providing lateral
stability to the walls, and to minimise the possibility of
shrinkage cracking at openings. Bond beam blocks should be filled
with concrete or grout as specified and suitable reinforcing
steel. Reinforcement should be not less than 12mm deformed bars.
Flashing
In cavity walls, flashing shall be placed at an
angle across the cavity to discharge moisture towards weep holes.
Turn up ends to prevent moisture draining into cavities. Flashing
and capping should be provided to the tops of all parapets.
Cleaning Care should be taken during construction of
masonry walls to prevent excess mortar being smeared over the
faces of the blocks. Finished walls should be cleaned down after
the mortar has hardened by rubbing with a piece of block or
carborundum stone, wire brushing where necessary. Acid must not be
used for cleaning concrete masonry walls.
