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How we built the shell and moved into an unfinished house in Uruguay

📅 updated 12 min
Straight answer: After pouring the strip foundation, we watered it for about ten days. BPS cost $900. We built 1.2-metre columns, an 18 cm C25 slab in two pours and cast concrete walls because they were cheaper than hollow brick. A septic system cost $1,200; the light-steel roof and sandwich panels cost about $6,000. Then we moved in unfinished.

After the strip foundation, construction did not simply race forward. There was watering, BPS, columns, the slab, walls, a septic system, heavy rain and finally the roof. This is how that stage went for us.

Watering the foundation and the first BPS bills

We watered the strip foundation for about ten days because the weather was very hot and the first days mattered. At the same time, the first BPS bills arrived: around $900 for a couple of weeks of work. The calculation was based on hours and not every day was full, but the number was still frightening.

Raising the house on 1.2-metre columns

While the foundation gained strength, we settled the column height. The building area sat below the road and had to be raised. We and the architect agreed on 1.20 metres, with an 18 cm slab above it.

The crew marked everything, installed reinforcement and made formwork for the corner columns. They had to mix and pour them by hand because holidays had pushed the concrete-plant queue out to a month. One column was poured every few days. Around the perimeter the plan also called for fourteen square columns of roughly 30 by 30 cm, plus a cross-shaped support in the centre.

For scale, an Artigas cement bag cost us about $5 and a cubic metre of stone about $30. Whether that is expensive depends on what you are comparing it with.

The columns took about a month and a half. We applied several waterproofing layers ourselves over a weekend: two 20-litre buckets at roughly $50 each. A mini excavator then filled and levelled the earth around the supports, so the structure stopped looking quite so massive.

Pouring the slab in two stages

We had enough formwork for only half of the slab and decided to reuse it rather than buy more. After several weeks of preparation, the mixer parked right beside the work, so we did not need a pump. The crew vibrated and levelled the concrete, then covered it with plastic. About four hours later it already felt like stone. We watered it daily, sometimes travelling by taxi when the builders could not go.

About ten days later, the crew prepared the second half while gradually recovering the formwork from below the first pour. The slab was strengthened with beams containing four 18 mm reinforcing bars in each strip. Rain cancelled the next scheduled mixer, but three days later the second half was poured.

Daily watering continued, and the roughly $30 return taxi rides added up. At the front, the 1.20-metre columns and 18 cm slab ended almost level with the filled ground; at the back the structure remained high. People suggested a basement or parking space below, but we were told the extra square metres would increase taxes. We filled around it and kept moving.

Casting the walls in concrete

After the completed C25 slab had rested for about ten days, the formwork came out. We decided against hollow brick because the builders said cast concrete would be cheaper. My parents agreed.

The team marked the walls, installed reinforcement and built formwork for the front. They mixed the concrete on site and lifted it with a winch to a mixer above. When the first wall emerged, neighbours came to look: poured concrete houses were unusual here, and people began calling ours a bunker.

Our money was disappearing while rent remained about $900 per month, so my parents wanted to move into our own place even without finishes. Rain interrupted work every few days. The walls kept rising, with wooden blocks holding the formwork at an even distance. Even the interior partitions were poured concrete.

The septic system and a battle with rainwater

Once more than half the walls were standing, we hired a Uruguayan crew for the septic system. A tractor dug the holes and lowered the concrete rings while I helped translate. They said a bottom was not used in our clay soil and that a pump-out truck, about $50 per visit, would probably be needed often. The three-hour job cost $1,200.

The next day a downpour flooded both chambers and shifted one ring. My parents bought a pump and emptied them. Rooms with finished walls became small swimming pools. We returned again and again to remove water; the septic chambers alone were pumped out about three times.

After almost two days of rain, water reached the foundation below the slab. At five in the morning we were outside digging drainage trenches with my parents. We worked in mud and rain for two days, stopping only to eat. We later realised that thousands of litres had entered through the open windows and doors and flowed toward the foundation.

The final walls, beam, gables and roof

The final wall and a large concrete roof beam took several more weeks. The gables were also concrete, about 60 cm high. That finished the concrete stage, followed by a few days for the last gable to gain strength.

The roof base used light-gauge steel profiles and took a week. In one day, with one helper, the builders covered it with roughly 3 cm metal-foam-metal sandwich panels. The panels cost about $6,000. Suddenly the house had a roof.

The shell was ready, but there was no toilet, no proper windows and no finished doors—only concrete and a roof. We decided to move in and finish it ourselves. Our first week there: /en/dom/zhizn-v-nedostroe/.

In short

Strip foundation → watering → 1.2 m columns → C25 slab in two pours → waterproofing → cast concrete walls → septic system and downpours → light-steel roof with ~$6,000 panels. BPS kept running and rent was $900, so we moved into the bare shell rather than pay for someone else's home forever.

Related

Finding builders and the foundation: /en/dom/poisk-stroiteley/. Paperwork: /en/dom/dokumenty-dlya-stroiki/. Buying the plot: /en/dom/uchastok/. Living unfinished: /en/dom/zhizn-v-nedostroe/.

FAQ

Why did we water the concrete?

The weather was hot, so watering during the first days mattered. We watered the strip foundation for about ten days and the slab every day, sometimes taking a taxi to the plot for roughly $30 return.

What concrete did we use for the slab?

We used C25 concrete. The 18 cm slab was poured in two stages because buying enough formwork for the whole area would have cost more. The Artigas mixer could park close enough that we did not need a pump.

Why did we cast concrete walls instead of using brick?

Our builders said poured concrete would be cheaper for this project, so my parents agreed. Even the interior partitions are concrete. Neighbours came to look and started calling the house a bunker.

How much did the septic system cost?

A Uruguayan crew dug the holes with a tractor and installed concrete rings in about three hours for $1,200. The next day's downpour flooded both chambers and shifted one ring.

Why did we skip a basement or large roof overhang?

We were told that extra covered area, including non-residential space, could increase the declared square metres and taxes. Even a roof overhang beyond roughly 15 cm could count, so we kept the design simple.

Something still unclear?

Ask about this article — I answer from our own experience. The good questions get added here as an answer.

Not legal advice, just our experience. Nothing is published without me.