How to build cement flooring under a container

The container comes complete with its own marine plywood floor-board and you might consider sticking a vinyl sheet over this to improve the aesthetic and safety considerations. For staging the containers, apart from just the pillars, a smooth cement flooring is essential because:

• Prevents the growth of weeds under the container which would have to be cleaned out occasionally.
• Prevents a rodent menace where they make burrows in the ground and might even burrow through the container plyboard especially if food is stored inside. A friend of mine who owns a container cafe had to undertake a very expensive foundation repair because of this.
• A smooth layer gives the entire structure a more permanent and sleek aesthetic appeal.
• In the event that the containers need to be moved or sold, you can easily convert this into a traditional brick and mortar structure by just building the walls and roof.

Although this post aims to breakdown associated costs for labour and materials, you may decide to use contract mode of payment. For more information on the work terms, you may refer to this post.

Materials

The materials required for the floor soling are boulders, jelly, cement and sand.

• About 1/3rd of the MSand went towards constructing an entrance slab over a drain channel. So, effectively only 2/3rd of the MSand cost ie 10k can be factored towards soling for the floor space under the container. Reduce above total cost by Rs 5k which gives Rs 28k.
• There may be some amount of jelly and boulders left over, but this can be factored as contingency.
• Total floor space covered by above materials is (8*20)*2 sft for 2 containers, which is 320 sft.

Total material cost per sft works out to Rs 28k divided by 320 sft which is Rs 88 per sft. So materials for soling of 1 container floor space is 160 sft multiplied by Rs 88 = Rs 14k. Keep in mind that with quantities lesser than the above mentioned lorry loads, expect logistics to cause an increase in cost of materials.

The same Mazda lorry used in this post was also used here. A point to note for the stone material is that, the smaller the size of each piece, the more expensive it gets. The big boulders which came in the same lorry was Rs 5.5k, the jelly-6 inch was Rs 8k and the smaller jelly-1 inch stones were Rs 9k.

Thickness of the soling plays a part in the quantity of materials. Just ensure the jelly adequately covers the floor space. A beading of boulders for the outline of the floor ensures a hard side wall which will prevent chunks of the soling breaking away.

Labour

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 work on ‘labour and materials’ terms. The contractors fee is also included in this amount. Labour shifts are tricky to reverse engineer because of multiple works at the same time and varying work capacities.

If the above labour cost is factored as a per square foot (sft) rate, then it comes up to Rs 10k divided by 320 sft which is Rs 32/sft. So for 1 container costs may come up to Rs 5k.

Total cost of material and labour per square foot of area for soling work comes up to Rs 88 + Rs 32 = Rs 120 sft

Conclusion

Soling cost for a unit area has been reverse engineered to an amount of Rs 120 per square foot. So total soling cost per container works out to Rs 19.2k. Different areas might have slightly varying costs, but for labour component, an appropriate per shift rate can be substituted and for materials the current rate for the quantity may be substituted.

While planning for your own builds, apart from the information provided here, it may be useful to factor for contingencies and essential extras. For example, depending on the intended use of the shipping container, you may want to construct an additional bathroom, gate, entrance soling slab etc. I will try to mention approximate costs for these in future posts.