WORK METHODOLOGY / PROCEDURE OF SOLID BLOCK / BRICK MASONRY & PLASTER WORK
TOOL AND TACKLES
GENERAL
Ø Blocks / Bricks shall be stacked on level ground.
Ø Blocks / Bricks will be preferably placed in 200mm height
( not width wise ) and the stacks should not be more than 8 to 10 in numbers in
height.
Ø For DPC course a layer of 100 mm thick PCC
(1:2:4 hand mix, only 10mm aggregate mixed) will be provided on first layer of
AAC block.
Ø Grade of blocks shall be finalized before
procuring and it shall be approved from client.
Ø RCC bend (Patli beam) will be provided at a height of 1 mt to 1.2 mt from top of DPC
level or as per drawing and specification.
Ø Reinforcement
for RCC bend : 2 nos of 10dia. horizontal
bar and link bar at 200 mm spacing and drill shall be done upto 50 mm deep in
RCC column or wall for horizontal bars.
Ø Ready mix mortar or any approved material
shall be used for filling the gap between RCC beam bottom and Block wall top.
Ø 10 to 20mm size of aggregate shall be provided
for metal packing at 50mm spacing at RCC beam beam.
MASONRY WITH SOLID BLOCKS / BRICKS
Ø Only approved ready made plaster shall be used for
jointing of Solid Blocks / Bricks.
Ø Block jointing mortar shall be approved from client
before using.
Or ordinary Cement mortar of ratio 1 : 4 shall be used (1
part Cement : 1 part Sand)
Ø Mix of jointing mortar shall be a homogeneous, lump free
mixture and ensure no dry mortar shall left unmixed at the bottom.
Ø Place the first line of blocks on concrete slab using
ready mix plaster mortar or cement mortar having 1 : 4 ratio (i.e.- 1 part
Cement : 4 part Sand).
Ø Ready mix mortar / ordinary Cement mortar shall be used
as a leveling course of 15 to 20mm thick.
Ø The blocks shall be placed in the direction of height
while doing the masonry work & The blocks shall be placed in the direction
of width.
Ø Pre-wetting of blocks / bricks is essential and post
application curing is required to the mortar joints for 7 days.
Ø Care should be taken to make sure that mortar applied on
the block uniformly.
Ø Racking shall be done at joints of blocks / bricks for
proper bonding of plaster
Ø At the junction between RCC and block / Brick masonry, GI
/ PVC chicken mesh shall be used to avoid cracks in the corners and
junctions.
Ø The height of Patli beam or distance of Mullions will be
provided at as per drawing and specification or as per advice of Client or
consultant.
Ø The work of concealed plumbing or the electrical wiring
fittings, etc. will be done in proper workman like manner using proper tools to
avoid damage to the blocks / Bricks and to avoid cracks in masonry work.
Ø The surface is now ready for plaster, at this stage pre
wetting to the Blocks / Bricks is essential before application of plaster.
Ø Plaster can be started after 7 days of constructing the
wall.
Ø Mullion is recommended at both the side of door frame for
better holding of door frame.
FIXTURES IN
AAC BLOCKS:
For fixing various fixtures, like door and
window frames, wash basins, electrical fittings, etc., to block / brick walls,
wire nails should not be used as they have low holding power. Use of aluminum
cut nails gives satisfactory results. It is recommended that they be skew
driven to obtain a dovetail effect.
a)
Door and window frames are attached in the surrounding masonry with 7”
aluminum or galvanized iron cut nails hammered directly into blocks / bricks. 14 gauge screws may be used,
and they should penetrate at least 75mm into the blocks / bricks and should
preferably be driven into rawl plugs. All screws shall be inserted into the
blocks and not along the joints.
b)
Wash Basin shall be fixed to the wall by using 3” x 14 gauge screws in
rawl plugs. Where wash basins are mounted on brackets, use of 4” x 14 gauge
screws in rawl plugs will give sufficient strength and rigidity.
c)
Light fuse boxes and switch boxes should be fixed using 3” x 10 gauge
screws in rawl plugs. Heavier fittings should preferably be mounted on the
floor or fixed with through bolts. Wall brackets, light switches, should be
fixed using 8-10 gauge screws, not less than 3” long in rawl plugs. Where
conduit runs are made on surface the supporting saddles may be fixed with 2” x
10 gauge screws directly into AAC blocks or where the conduit is likely to be
subjected to loads during the erection, by 8/10 gauge screws in rawl plugs.
d)
Wherever possible handrails should be fixed using 4” x 14 gauge screws
in rawl plugs.
Ø
Before taking up plastering work it shall be confirmed whether concealed
electrical and plumbing lines are completed and tested.
Ø
The surface to be plastered shall be chipped off any projection, brushed
off for dirt and efflorescence and hacked off (for RCC only).
Ø
All substrate defects shall be patched up before plastering.
Ø
The surface shall be well soaked and touch dry before starting plaster
work to avoid absorption of water present in the mortar by the dry masonry.
Ø
Any admixture to be used in the mortar to be decided and approved in
advance and used as per manufacturers recommendation.
Ø
Quality of Ready Plaster shall be approved in advance if ready mix
plaster is used.
Ø
Mix one bag 40kg ready mix plaster with approximately 7 to 9 liters of
water is recommended or as per manufacturer guideline.
Ø
Mix thoroughly for 3 to 10 mins until the desired homogeneous mix is
achieved.
Ø
For conventional plaster cement sand ratio of 1 : 4 (1 part Cement : 4
Part Sand) is recommended.
a. Machine Mixing b. Manual Mixing
Ø
Ensure the mix is free from lumps before use.
Ø
The mortar shall be prepared on watertight platform and consumed with in
90 minutes after adding water.
Ø
Number of layers, thickness of each layer and type of final surface
finish shall be decided as per requirement of drawing/specification.
Ø
In case of two coat plaster, top surface of first coat shall be kept 12
mm in thickness with zigzag lines (but leveled) for proper bond with top coat
of 8 mm in thickness.
Ø
Succeeding coats shall not be applied before 24hrs of first coat
plaster. Lines, levels and corners are to be properly maintained before
starting of second coat of plaster.
Ø
When the work is suspended at the end of the day, the plaster shall be
left cut clean to line both horizontally and vertically.
Ø
When plastering is resumed the edge of the old work shall be scraped,
cleaned and wetted with water before plaster is resumed.
Ø
Intermittent curing for Block / Brick Masonry to be done for a period of
7days.
Ø
Curing for Plastering to be done for a period of 7 days.
Reference Documents
|
Sr.No |
Document No |
Title |
|
1 |
IS:2185 |
Block Specification |
|
2 |
IS:6041 |
|
|
3 |
IS 1542 |
|
|
4 |
IS 8112 |
|
|
5 |
IS 1489 |
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