1. Subject: Maintenance and rehabilitation of
structures
(3360605)
Topic :Repair of stone masonry
Prepared by :Nishant Parekh
2. Stone masonry
The construction of stones bonded together with
mortar is termed as stone masonry where the
stones are available in a abundance in nature, on
cutting and dressing to the proper shape, they
provide an economical material for the
construction of various building components such
as walls, columns, footings, arches, lintels, beams
etc.
3. Classification of stone masonry
• Broadly there are two types of stone masonry, namely:
1. Rubble Masonry
2. Ashlar Masonry
3. Rubble masonry:
• This consists of blocks of stones either undressed or roughly dressed and
laid in suitable mortar, having wider joints which are not of uniform
thickness.
A. Uncoursed random rubble masonry
B. Random rubble masonry
C. Coursed rubble masonry
D. Dry Rubble masonry
4. Types of Stone Masonry
• Based on the arrangement of the stone in the
construction and degree of refinement in the
surface finish, the stone masonry can be
classified broadly in the following two
categories
• 1. Rubble masonry
• 2. Ashlar masonry
5. Repair Cracks in Stone Masonry
• Repairing the mortar joints and cracks in stone masonry is
referred to as re-pointing, or tuck-pointing. An unrepaired joint
or crack in brick or stone foundations can lead to more severe
problems down the line. As the foundation settles, the rest of
the house settles with the changes in the foundation, which can
manifest in plaster cracks, or doors and windows being
difficult to open or close properly. Once you properly repair
cracks in stone masonry, you can slow the effects of this
settling.
6. Stonework repair
• Where stone repairs are specified, an assessment will be made on site as to
the most appropriate method using the joint experience and expertise of the
stone mason and architect. This should be undertaken as soon as close
inspection (through erection of a scaffold or use of a cherry-picker) is
possible.
• Stone should only be replaced or repaired where identified by the architect
and any further stonework thought to require replacement and not shown
on the drawings, should be marked up with chalk to allow for further
inspection. The contractor must check with the architect if the drawings /
instructions are not clear.
7. Methods of repair stone masonry
• Clean the crack with a wire brush. Remove any larger loose particles with a
chisel and hammer as needed. Don safety glasses and a dust mask. Blow
out the debris with the blower attachment of an air compressor hose to
eliminate any fine particles from the crack.
• Use a pointed trowel to thoroughly fill the cleaned crack with vinyl
concrete patcher stained to match the colour of the stone masonry. Fill the
crack to the surface of the masonry, and scrape away any excess with the
trowel.
• Allow the patch to dry for 24 hours, then sand the filler with medium-grit
sandpaper to blend the patch to match the surrounding stone.
8. Re-Laying Stones
• This involves removing damaged masonry surfaces and
installing new ones that will match with the surrounding
materials. This kind of work is often performed on: driveways,
sidewalks or paths, patios, porches, pool decks,
siding, chimneys, garden paths, and etc.
9. Capping Stone Features
• This is a technique often used on the top of masonry walls to prevent
damages further on down the road. They can help with minimizing
maintenance while actually extending the life of the wall itself. This is
often used on retaining walls and other types of standing decorative
surfaces.
10. Remove the Stone
• To return a popped stone to its original position, drive wedges
between stable stones to take the weight off the popped stone.
Work the popped stone out of the wall carefully, without
dislodging the other stones. Drive the wedges into the wall
slightly further.
11. Chip Out Mortar
• Carefully chip out the damaged mortar with a thin cold chisel
and a small sledgehammer. Clean the joint until you reach
solid mortar.
12. Mix New Mortar
• Mix new mortar to a consistency for use with a mortar bag and
fill the bag. Mist the joint with water from a spray bottle and
squeeze mortar into the joints.
13. Pack Each Joint
• Pack each joint tightly with a pointing trowel, adding more
mortar if necessary. Tool the joints to match the original and
remove excess mortar with a stiff brush.
14. Insert Stone
• Mist the cavity and spread mortar on the bottom of the cavity
and the top and sides of the replacement stone. Insert the stone
and push it into place using the pointing trowel. Pack mortar
against all sides of the stone. When the mortar has set, tool it
to match the original.
