Cheap foundation pillars for a shipping container

I decided to go with a solid concrete foundation for staging the shipping containers which was to become a shop. Getting in to the project, I had no idea about how much of tangible ‘brick and mortar’ construction could be built for a certain amount of money. There were too many variables to get a proper picture. Through the details below, I hope to give you a general intuition for understanding the costs involved in construction.

Terms of work

• Most kinds of labour, here in Coorg, operate on either a ‘contract’ rate or ‘labour and materials’ where you can pay directly for the materials and the fixed labour wages for each day of work.

• Although the second option suggests more controllable costs, unless you know the number of days and shifts of work required, you might end up spending a lot more money on unproductive work days. Rain might also prove to be costly in this case.

• In the first option, the contractor will give you a round figure. You can accept this but it is useful to set a guarantee of quality and quantity of work with him. The risk of this option is that you may have paid more than that work deserves as per market standards.

What I chose and why

Initially I decided on the first option where the contractor gave me a fixed cost which included materials and labour. A contractor who has knowledge about how many shifts of labour work is required for the job, will benefit from potentially getting more work done, sooner, consequently making more money. This was also good for me as a construction novice and I did not have to worry about unproductive work. Also, since the cost was fixed, it helped in budget planning.

Here I will try to reverse engineer the costs of labour and materials so that it can help in future decisions, and give you the confidence to choose the second option which can save you a lot of money! Refer to this post on foundation for a shipping container, to get a better picture about the usage of materials and layout.

Materials required

The materials for constructing concrete pillars are cement, sand, jelly, boulders, and steel rods. There was also a bathroom being built at the same time and it was a little difficult to point out exactly how much resource went only to the pillars. However I have given outer limit calculations the quantities and cost should fall inside this.

Reverse engineering the materials cost for 1 pillar

• From the above, 10% of cement can be assumed to have gone towards the bathroom. Significant quantity, maybe 30% of the steel rods has gone towards making a RCC (concrete) slab of 8ft*8ft*0.5ft for the bathroom roof.

• For the jelly, which was used for the pillars and also RCC (concrete) slab, we can make some assumptions. The volume/dimension of each pillar is 5ft*1ft*1ft and there are 12 pillars for a total volume of 60 cft(cubic feet). The RCC slab has a volume of 32 cft. So only about 2/3rd of the jelly was used for the pillars.

• The lorry load of sand was also sufficient for the masonry of the bathroom foundation and walls.

The main reduction from the total cost is the steel rods so let us deduct 30% ~4k from the above total and factor the surplus of other materials like jelly, sand and boulders as contingency. This gives us a cost of Rs 44k for 12 pillars. Therefore the cost of materials per pillar of height 5ft (2ft above ground and 3ft below) is Rs 3.7k.

After the pillars have been setup, the boulders are filled only on the inside area of the foundation under the container profile.

The lorry is quite heavy when loaded and caused the pavers (ground tiles) to break and sink at certain places. So consider the unload spot for your material, especially in rainy season. The truck, a Swaraj Mazda, with a full load of sand weighs about 12 tonnes and with jelly/boulders, is about 14 tonnes.

Labour shifts

There was another construction being built by the same contractor close to my spot, so the workers did not necessarily spend the whole day with this work. So the separate shifts for masons and other workers may not be too accurate. However, the cost below is mentioned by factoring for masons and other workers at a fixed rate of Rs 1000 per shift, which is how the contractor charged for additional work on ‘labour and materials’ terms. In this way, the contractor’s fee was charged as a proportion of the number of workers.

The quality of work aspects like precise measurements and water level between the pillars, is crucial for the shipping containers, since 4 pillars are the only supporting structures. An empty container weighs 2.5 tonnes.

Number of work shifts required

In the below table, the number of shifts for each type of work and associated cost is mentioned. The worker shifts are mainly by 2 types of workers, the masons who are about Rs 800-1000 per day and the others who are Rs 600-800 per day. 1 shift is considered as 1 person working at the spot for 1 day.

Since I had initially agreed to a contract rate, I ended up paying more than required which I could only retrospectively analyse. Given below is how much you could expect to pay for the labour, on ‘labour and materials’ terms to setup only the pillars.

The pillars at the ‘L’ junction where the 2 containers meet are 2ft wide to accommodate both and so the above labour cost is for casting 10 pillars. So for each pillar it works out to approximately Rs 2300.

Important

In my case I have constructed 6 pillars for each container, but practically you only need to construct 4 for each container. Materials and labour cost per pillar is Rs 3.7k plus Rs 2.3k which comes up to Rs 6k per pillar. So for a single container with 4 pillars, you would need to budget Rs 24,000 for constructing concrete pillars. Ensure to add a contingency of about 10%-15% to be on the safer side.

Remember, this is the cost for the most basic but strong foundation of just the pillars and not the smooth cement floor under the container. The details for the smooth ‘soling’ layer will be mentioned in another post.

Check the video below describing different steps in setting up the pillars: