1. GUIDELINES FOR
CONSTRUCTION OF
MASONRY WITH
SIPOREX BLOCKS
271246 Puppala Vamsee
271247 Helen Anitha R
271248 SRINAATH R
271249 Priya Rajeev
271250 Vikhyat Ramachandran
271251 Chinmai G Rao
271253 Nirman Rathi
271254 Riv Mahesh

2. SIPOREX UNREINFORCED BLOCKS
Available in the following dimensions
Oven dry density
-450 Kg/Cum
Thk X Height X Length
075 x 240 x 650 mm
100 x 240 x 650 mm
Oven dry density
-600 Kg/Cum
Thk X Height X Length
125 x 240 x 650 mm
150 x 240 x 650 mm
200 x 240 x 650 mm

3. GENERAL
1. Details of sizes of blocks for walling, partitions & cladding are given in the price list.
2. Blocks should be stacked in dry, well ventilated areas on a level ground.
Block should be placed on edges (in the direction of 240 mm height)
not on flat (in the direction of the thickness). Different stacks should be
maintained for different sizes of blocks.
3. Siporex blocks should not be used below ground level or in plinth.
4. Damp-proof course should be provided before starting superstructure masonry.
5. Generally, load bearing structures using 20 cm (8”) Siporex blocks can be
constructed up to two storeys, i.e. G + 1 Buildings. Over G+2, will be a “Framed”
structure.
However, it is necessary to design load bearing / partition wall as per relevant IS
specifications.
6. Siporex blocks and slabs are highly suitable for extension or addition of floors to
existing old or new buildings because of their lightweight characteristics

4. MASONRY WITH SIPOREX BLOCKS
1. Cement mortar 1 : 6 using Portland cement should be used.
2. Blocks shall be placed in the direction of 240 mm height in the masonry.
3. It is not necessary to soak the Siporex blocks before their use in masonry. Their
surface should be wetted sparingly and afterwards water should be sprinkled for
curing of masonry joints.
4. For breaking of joints in the masonry, specifications for brick masonry work shall
be adopted for guidance.
5. At door and window openings, 2 nos. 6 mm dia bars should be provided at the top
of the openings to avoid cracks on plaster. The bars should be provided in the
course immediately above the lintel and bar should be extended 0.6 m on both
sides.
6. Inter-locking should not be done at junctions of load bearing and non-load bearing
partition walls. Connections between these walls can be achieved by:
a) Nailing galvanized strips across every third joint with 12 mm galvanized or
aluminum nails, or
b) By providing 6 mm dia bars 200 mm long at the Junction.

5. Siporex blocks are wetted before being
laid in construction of walls.
Top: A wall built using siporex blocks
Bottom: Stacking blocks, on site

6. MASONRY WITH SIPOREX BLOCKS
7. Inter-locking at junction of 2 load bearing walls should be done as in brick masonry.
At the junction between conventional and Siporex block masonry, chicken mesh
should be provided in the plaster to avoid cracking at the corners and junctions.
8. Bond beams, 200 x 100 mm (8" x 4") should be provided throughout the load bearing
walls below the Siporex slabs for floors and roofs, e.g. if there are three rooms with
continuous wall, bond beam should be continuous with 12 mm dia bars. 2 Nos. and 6
mm dia bar stirrups of 175 mm (7") centre to centre shall be provided as
reinforcement.
9. For Unsupported Siporex: Walling height ≤ height 18 times the thk of wall and
……………………… horizontally ≤ 24 times thk of wall for load bearing walls.
For partition or non load bearing walls unsupported length and height should be:
≤ 30 times the thickness of walls.
In cases where the length of wall exceeds these limits, Siporex pillars can be
constructed. If height exceeds the prescribed limit, bond beams at a suitable height
in the wall should be provided (IS-6041 and IS 1905) .
10. The work of concealed plumbing & concealed electrical wiring fittings, etc., should
be decided in advance. Work of chasing should be done in Siporex blocks with
proper tools to avoid damage to blocks & to prevent cracks in plaster.

7. INTERNAL AND EXTERNAL PLASTER
a) Siporex walls should generally be plastered on both sides in two coats.
Internal walls in industrial buildings may be left unplastered if so desired
and joints should be properly finished.
b) Block walls should be wetted sparingly before plaster.
c) Method of plaster is similar to that of plaster on brick1 concrete walls.
d) Internal plaster should be carried out in 2 coats with cement mortar 1 : 3
(One part of Portland cement and 3 parts of screened and washed sand).
First coat may be of 4 to 6 mm thick and the second coat (finishing coat)
e) External plaster should be carried out in 2 coats with cement mortar 1 : 3
(One part of Portland . cement and 3 parts of screened and washed sand.)
First coat may be of 8 to 10 mm thickness and the second coat (finishing
coat) may be about 10 mm thick.
f)Plastered surfaces should be watered for at least one week.

8. PAINTING
a) INTERNAL PAINTING
• For plastered walls the method employed is the same as for other plastered walls.
• For unplastered walls in industrial buildings, berating paints such as acrylic
emulsion can be applied. They provide a more impermeable surface and are often
washable.
b) EXTERNAL PAINTING
• For exterior painting of plastered walls, where whitewash is the most common
method. Longer life and better weather protection is obtained with a cement
paint. Better moisture protection is obtained with all cement paints by application
with a stiff brush raher than by spraying

9. FIXTURES IN SIPOREX
a) DOOR AND WINDOW FRAMES:
Door and window frames are attached in the surrounding masonry with 7" aluminum or
galvanized iron cut nails hammered directly into the Siporex blocks. The nails should be spaced
at a maximum 40 cm and the first nail should not be farther than 20 cm from a corner. 14
gauge screws may be used. They should penetrate at least 50 mm into the Siporex blocks and
should preferable be driven into raw plugs. ALL NAILS AND SCREWS SHALL BE INSERTED INTO
THE BLOCKS AND NOT ALONG JOINTS.
b) WASH BASINS:
Pedestal type wash basins are fixed to the wall using 3" x 14 gauge screws in raw1 plugs. Where
wash basins are mounted on brackets, use of 4" x 14 gauge screws in raw1 plugs will give
sufficient strength and rigidity.
c) CUPBOARDS:
For most purposes, 3" x 14 gauge screws in raw1 plugs should prove satisfactory. For heavily
loaded cupboards, timber connector should be used between cupboards and Siporex walls, in
addition to screws in raw1 plugs.

10. FIXTURES IN SIPOREX
d) ELECTRICAL FITTINGS:
-Light fuse boxes and switch boxes should be fixed using 3" x 10 gauge
screws in raw1 plugs.
-Heavier fittings should preferably be mounted on the floor or fixed with
through bolts.
-Wall brackets, light switches, should be fixed using 8 to 10 gauge screws,
not less than 3" long in raw1 plugs.
-Where conduit runs are made on surface the supporting saddles may be
fixed with 2" x 10 gauge screws directly into Siporex or where the conduit is
likely to be subjected to loads during erection, by 811 0 gauge screws in
raw1 plugs.
e) HANDRAILS:
Wherever possible these should be through-bolts. Failing this, use 4" x 14
gauge screws in raw plugs.
f) HOT AND COLD WATER PIPES:
The supporting brackets or holderbats should be fixed to walls using 2"x 10
gauge screws in raw1 plugs.

11. PRECAUTIONS
AGAINST CRACKING IN BLOCKWORK
1. Limit the cracking to the joints, so that it can be repaired easily. Hence, mortars
weaker than the blocks are always recommended.
2. Where uneven settlement of foundations is feared, proper bonding and the use of
reinforcement in horizontal joints will tend to reduce risks of cracking by
distributing stresses throughout the wall.
3. In block walls abutting against columns and beams of load bearing frame,
differential movements can be caused by settlement, variable loading conditions
and changes in temperature and humidity.
4. For blockwork partitions, care should be taken to limit deflection of floors or
partitions should be strengthened by use of bond beams or reinforcement in the
lower courses.
5. Use resilient material stoppers between door shutter and wall at one or two points
or use door closer to avoid cracking in walls by impact of slamming of doors, etc.,
particularly in these rigid partitions.
6. Alleviate temperature & shrinkage stresses in the wall by incorporating control
joints at appropriate intervals and locations.