Masonry

INTRODUCTION :

Masonry is defined as the construction of stone, brick or tile bonded with mortar .The selection of material for masonry work depends on following properties of the material :-

1. Strength
2. Durability
3. Porosity
4. Thermal insulation
5. Fire resistance
6. Dead weight
7. Economy

Masonry is generally defined as a walling material. Masonry walls are divided into two categories:

1. Load bearing walls
2. Non-load bearing walls

Masonry can also be broadly divided depending upon the type of material used, into following types:

1. Stone masonry
2. Brick masonry
3. Reinforced brick masonry
4. Composite masonry
5. Hollow concrete block masonry
6. Load bearing wall tile masonry

Most commonly used masonry types are stone masonry & brick masonry.

STONE MASONRY:

It is a process of masonry construction by using stone & mortar. Stone masonry is further classified in two types depending on arrangement of stones, shapes, finish etc.

1. Rubble masonry
2. Ashlar masonry
   
   1. Different categories of RUBBLE MASONRY:
      
      1. Uncoursed rubble masonry
      2. Random rubble masonry
      3. Coursed rubble masonry
      4. Dry rubble masonry

1. 1. Different types of ASHLAR MASONRY:
      
      1. Ashlar fine
      2. Ashlar rough tooled
      3. Ashlar rock, rustic or quarry faced
      4. Ashlar chamfered
      5. Ashlar facing

Following are the general points to be observed in stone masonry construction:

1. Stone used should be free from cracks, flaws, cavities, veins and patches of soft or loose material i.e. it should be hard ,tough and uniform in texture.
2. Stones should be laid upon their natural bed i.e. position occupied by the stone during its formation.
3. Proper bond should be maintained throughout the masonry work.
4. Through-Stones should be used for good bonding in facing and backing of wall.
5. Through-Stones should be laid in a staggered manner in the successive course.
6. As far as possible, all connected walls in a structure should be raised up uniformly & regularly.
7. Pockets & hollows left, should be filled with mortar and stone chips
8. The joints should not be too smooth & dressed hollow.
9. The vertical joints should be staggered.
10. The vertical surface should be truly vertical & checked by plumb bob.
11. Development of Tensile stresses in masonry should be avoided.
12. Pointing is necessary for exposed joints.
13. All joints shall be filled with mortar to a depth of 25mm.
14. RCC coping of 100 mm thickness, is necessary on the top of wall
15. The entire work should be cured for atleast 15 days.

BURNT BRICK MASONRY:

INTRODUCTION :

Brick masonry is defined as construction of bricks by bonding them together with mortar.

The strength of brickwork depends on quality of material used and process adopted for work. Burnt brick masonry is classified as first class and second-class according to the type of bricks used & method adopted for laying.

MATERIALS REQUIRED FOR BRICK MASONRY:

1. Bricks
2. River sand/Crushed sand/Stone Dust
3. Cement
4. Water

BASIC REQUIRMENTS BEFORE COMMENCEMENT OF BRICK WORK:

1. Site engineer to prepare & mark out different types of brick masonry on floor plan. i.e. thickness of wall and get it approved from higher authority.
2. Line out of every wall on the floor is most important part of the masonry work. Approval has to be obtained from higher authority for this work.
3. Lineout must be done before starting of brick masonry work. The Project-Incharge must check the same with working drawings, for wall thickness, openings and room dimensions, before commencement of

Masonry Work.

1. All the materials required i.e. bricks, sand, cement, water, door frames, m.s.windows, tools plants& required manpower; should be made available in advance.
2. All the changes or alterations or omissions should be confirmed in advance.

CHECKING OF LINE OUT WORK:

1. Check the face of the layer in plumb with respect to face of beam.
2. Confirm the top of 1st layer is in one level.
3. Check room dimensions with diagonals of the room.
4. Check overall out to out dimensions of the floor.
5. Get the line out work checked by Project Incharge & approval by higher authority.
6. All positions of windows, doors and openings should be finalized at the time of line out,

CONSTRUCTION OF BRICK MASONRY:

1. Cleaning of floor slab should be done before starting of work and after daily masonry work.
2. All materials and mortar mixing trays should be shifted to work place.
3. Bricks should be thoroughly soaked in water.
4. The bond to be used shall be decided beforehand for the masonry work. Some of the bonds are:
   
   1. ENGLISH BOND
   2. FLEMISH BOND
5. Making line out work and getting approval for the same.
6. Proportion of mortar may be kept as 1:6 for wall thickness more than 100 mm and as 1:4 for 100 mm thick walls.
7. The bricks should be laid on full bed of mortar. All the courses should be laid truly horizontal and all the vertical joints should be truly vertical, i.e. use of level tube and plumb bob is necessary.
8. Avoid use of brickbats except when it is absolutely necessary for specified bond
9. Thickness of joint should be 12 mm to 15 mm
10. Bricks must be laid ‘frogs pointing upwards’ and avoid laying of brick on edge.
11. The face of joints should be raked to a minimum depth of 10mm.
12. Required provision shall be made to collect the mortar falling down during construction to avoid wastage.
13. Brick work should be done simultaneously in uniform level and is to be raised not more than 1.2m everyday .
14. Check and confirm the lintel level to place the RCC lintel.
15. Fill the masonry and RCC junctions with rich mortar ( i.e. 1:2 proportion ) and insert 20mm metal in the joint.
16. Place RCC band 100mm thick on half brick thick wall at an interval of 1.2m. Place RCC band at all window and opening sills with minimum penetration of 150mm in walls.
17. All the finished masonry work must be cured at least for 7 days

FIXING OF WOODEN DOOR FRAME OR M.S WINDOW:

1. Check the size of section and design of frame as per specification.
2. Check the size of doorframe. Fix minimum 3 holdfast/column Patti on each side before fixing the frame.
3. Concreting for holdfast is necessary.
4. Apply coal tar to the hidden side and wood primer to exposed side of the frame.
5. Check if the temporary supports are provided at bottom, middle and top two corners.
6. Check inner dimensions of the frame at bottom middle and top.
7. All the frames should be at one level.
8. The frame should be in plumb and level.
9. An offset should be maintained between the outer faces of the frame and the brickwork; to accommodates the required thickness of plaster.
10. Temporary supports provided to the frames shall be maintained in place till the completion of masonry.
11. Cleaning of the frames & floor shall be done immediately after the day’s scheduled work.