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|Guide to Re-pointing Masonry|
All masonry after time and erosion will tend to break down and start
to cause damage to the mortar pointed joints. Elements such as
freezing and thawing in cold weather will also cause the mortar joints
to deteriorate. Expansion and contraction from extreme thermal changes
can exceed the capabilities of the mortar and cause the joints to
Mortar provides a number of essential qualities to masonry: the
strength that holds the brick, stone, or block together; a cushion
between individual masonry units; and a water-resistant barrier that
prevents moisture and other damaging agents from entering the
Extreme stress on a structure can also cause mortar to crack and
eventually fall out this exposes the building to dampness through the
walls. At this stage a course of action is required either to repair
or replace any deteriorated mortar between the courses of masonry.
You may be required to carry out a total examination looking out for
any signs of deterioration: cracks in the mortar, loose or missing
mortar, weak or crumbly mortar, gaps between the mortar and the
masonry, loose bricks, water leakage on the interior of the wall, or
damp spots on the surface of the masonry. These are all warning signs
that if ignored can result in further degeneration of the mortar
joints, and the overall fabric of a structure will be damaged.
Rake out all the old pointing with a thin cold chisel. This method is
best used where care must be taken to prevent damaging surrounding
brick-work, the use of hand tools will cause the least amount of
damage to adjacent areas. Hand-held chisels can be chosen to match the
width of the joint and ensure that the impact is directed against the
mortar and not the masonry. Many sizes and types of chisels are
The cold chisel is placed into the joint and struck with a hammer to
disintegrate the mortar. A second tool, a joint rake, may then used to
clean out the resulting cavity. This method allows precise depths of
mortar to be removed. It is the slow method, but will result in the
least amount of damaged brickwork.
Re-pointing the Mortar Joint
Once the mortar has been mixed, the joint should be filled as follows.
A suitable length of joint should be chosen to repair at one time. The
joints should not be overly filled with mortar. Overfilling will leave
an appearance of an extra-wide joint that will look uneven due to the
geometry of the masonry.
Shaping the Mortar Joint
Shaping the correct mortar joint should only be done when the mortar
has just set or tested thumb-print hard. The shaping will play an
important part in the overall look of the masonry re-pointing work. To
keep the look of the building uniform, all re-pointed mortar should be
shaped in the same manner as the original work. Using the original
shaping techniques will make the mortar joint appear similar to
surrounding joints that may not have required re-pointing?
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