Some useful guidelines for constructing parapet wall

Parapet wall stands for a protection wall that can resist the collapsing from terrace to ground. Different types of parapet walls are found which range from brick wall masonry parapet wall, wooden handrail, iron grill etc.

Size of parapet wall:

1. Thickness of parapet wall should be minimum 9''. (full brick parapet wall)
2. Half brick parapet wall is not recommended for use.
3. Height of the parapet should be minimum 3'0''.

Once the centering and shuttering from roof slab bottom is detached, some deflection may happen at mid span of roof slab (positive bending moment). Similar thing will happen at support like negative bending moment.

With a view to prevent negative bending moment at support, huge amount of loads are required as downwards. In case of constructing the parapet wall as half brick wall, the roof can’t be prevented from uplifting. If the parapet wall is constructed as minimum 9'' thickness and minimum 3'0'' height, the roof slab can be prevented from uplifting. Therefore, different types of cracks at bottom of ceiling will be captured. To get rid of uplifting of roof, the centering & shuttering should be eliminated once the entire full brick parapet wall is constructed.

If the first floor is extended in future, the existing parapet wall should not be dismantled in case the wall is constructed as 9'' thick.

Assume, the parapet wall is constructed as half brick wall, now it is required to demolish the current parapet wall up to roof and make it as 9'', therefore, extra money will be incurred up to sill level of first floor.

While erecting half brick parapet wall, brick pillars should be arranged at regular interval ( 5 to 6 feet). Inner surface of parapet wall does not include flat surface since lots of offset will be created. Therefore, some problems will arise in waterline and sanitary plumping works.

Water from pump and discharge from water tank will be influenced with various offset produced with half brick parapet wall.

No tie exists for half brick parapet wall. As a result, wind pressure may provide some effects. Sliding of parapet wall may also happen.

If the column height is terminated for the height of the parapet wall (3 feet), it is required to dismantle for overlapping in future first floor construction. Adjacent Brick parapet wall will also be affected. If the height of parapet wall remains 3 feet, the column height should be increased for extra height for future overlapping. Then the column and parapet wall will be protected from over damaged.

Conclusion:
It is recommended to construct full brick parapet wall for minimum height of 3 feet devoid of half brick parapet wall.
There should be some provision for column for future overlapping.



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Published By
Rajib Dey
www.constructioncost.co
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About the Efflorescence on Brick masonry, its causes and treatment techniques

About Efflorescence on Brisk Masonry: It is often a white or a brown green or yellow powdery material which can be observed mainly in the winter season and it is produced from the mix of soluble salts and water.

The salt would drop on brick masonry and palpable itself as efflorescence when the water disappears and the color of the efflorescence is based on type of created salt. This efflorescence might vanish in summer but remains for the whole year.

Cause of Efflorescence on Brisk Masonry: There is a unique condition of occurring efflorescence and all the conditions should be met otherwise the brick masonry would suffer. There are three main three conditions offering the best conditions for efflorescence formation on brick masonry wall which are discussed here:
• The wall should be contained with soluble salts and that could be presented in masonry brick, mortar, adjacent soil and backing material.
• Water has to present in the brick masonry wall with the contact with soluble salt for the surface where water can be evaporated and left the salt.
• This wall will acquires pore structure for permitting the migration of soluble salt for dissolving it.
• And last of all, all the above conditions should be present for creation of efflorescence.

Factors affect the Efflorescence on Brisk Masonry:
• Temperature: An effect of high temperature falls on the efflorescence as it disappears water prior to reach the brick masonry surface.
• Water: Efflorescence is also frequent in water as water takes some time to reach the surface of the brick masonry.
• Wind
• Humidity

Sources of materials cause Efflorescence on Brisk Masonry:
• Soluble salt: There are a few sources for instance brick masonry, block masonry, mortar constituents like cement, sand, lime and admixture, grout components including cement, sand, aggregates and admixtures, contacting soil and ground water. The salts may be produced as the reactions between various constituents of brisk masonry walls and all soluble salts has the capability of producing efflorescence, like carbonates silicate, sulfate and chloride.
​• Moisture: The main source of it is the rain water especially which are wind driven and penetrate considerable water quality into the well.

Detrimental effects of Efflorescence on Brisk Masonry building: It generally damages the artistic value and the maintenance of the building. But it does not affect too much in the inner side of the building.

Control over Efflorescence on Brisk Masonry: The three conditions that are responsible for this should be controlled and proper action should be taken and as they are removal so can be washed to keep the bricks safe. But the thing is only removal and cleaning is not enough so it is required to seal the wall to avoid the problem permanently.

For more information follow theconstructor.org



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Published By
Rajib Dey
www.constructioncost.co
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