Your complete guide to culvert balloons


Despite Kenyans’ familiarity with side ditches and culvert, there is still a lot of ignorance regarding how these structures are made.  The article below is a guide on culvert balloons; their uses, structures made from them and a few precautions regarding them.

Before I begin, I knew some people (just as I did whilst I was ignorant) might ask,’ What is a culvert balloon?’

Well, I will define it in the simplest way possible.

Have you ever seen those huge cylindrical concrete tubes that are placed on the ground and serve as some sort of open drain? Those are culverts.

What is a culvert balloon?

A culvert balloon is therefore a cylindrical rubber bag that can expand and shrink when air filled, that is used in the construction of structures such as culverts. They have been in use for a very long time; making several structurally important structures.

What are these structures?

Well, we are all aware of the culvert as I believe they are the most common product of these bags (seeing how the bags were named after them). Culverts are tunnel bridges, largely found along roadsides that provide a route for water in case of heavy precipitation.

Often associated with culverts are side ditches, and these are also derived from culverts. The function of a side ditch is to direct flow of water, most likely to an outlet.

Culvert balloons are also used to make roof trusses, which are just a frame work of wood and/or concrete that are used to provide support for the roof. Here, culvert balloons are used when the design is cylindrical. Irrigation channels can also employ the rubber balloons when making concrete water tunnels.

How does it work?

Culvert balloons are made of rubber and therefore elastic. To be used, they have to be filled with compressed air after a releasing agent has been applied. As you have probably guessed, the releasing agent is applied to prevent the concrete from sticking to the bag permanently. The concrete mixture is then poured on the rubber bag and then let to dry.

After drying, the bag is removed, leaving behind a nice hollow cylinder, primarily though nowadays, prefabricated capsules have enabled a number of shapes, such hexagons, possible.

What are my considerations when buying one?

Look for the most durable rubber bag you can find. A good rubber-nylon compilation ought to last you a long time. Also, check on the price of the bag. Thankfully, a culvert balloon price in Kenya is quite fair as they have been in use for quite some time now.

Ensure that you purchase from a trusted supplier. You can look up popular and highly rated dealers and choose the one that sates you.

What are the precautions when using one?

Whenever using a culvert balloons, always have the engineers design in mind. These come to play when designing trusses and beams. Culvert balloons filled with compressed air and therefore care should be taken to prevent accidents as a result of sudden pressure release.

Seeing how they are rubber bags, extra care is to be taken when around sharp objects such as twisted steel bars and rods.


Culvert balloons are flexible rubber bags that are used in a large array of building activities such as construction of culverts, side ditches, trusses and irrigation canals. To be used, they are filled with compressed air and coated with realizing fluid to create a number of shapes, principally cylinders. One should look out for quality and price when buying and should take care when using one as they contain pressurized air and are made of rubber.

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