Ask HN: Why does it take a year to construct an apartment building? | Hacker News Reader

Ask HN: Why does it take a year to construct an apartment building?

11 pointsqprofyeh17 comments

Of course in Asia there are extreme cases where buildings are constructed in a day or a week. But on average, with modern quality and safety in mind, it takes up to a few years to complete the construction of a 10 story apartment building. Why is that?

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There are some objectively needed times (i.e. maturing of concrete, mortar, paint, etc.) and some (a lot of) times deriving from the general organization of the builder (and of the building industry as a whole).

People (workers) when available are not easily organized as "on demand", in a construction site there are phases when you may want to have 100 people on site for - say - 1 month, but the month before you only need 30 and the month after you only need 30, what happens is that the 1 month time becomes 3 months+, because you top at a constant 30 people for more months.

In some cases you can use sub-contractors for increasing production, but it is not like they are at home doing nothing waiting for your call, they are actually "booked" (often over-booked) months in advance, so you have to sychronize the site with their schedule, then it takes time to do all the contracts/paperwork according to norms, have them approved, etc..

Then there is weather, whether it is too rainy, too cold, too hot or too windy for this or that part of the work usually you have several days a year of no activity possible, and the way the project schedule is conforming to seasons may make a large difference, particularly for periods shorter than 18-24 months.

Given that we've been constructing building structures over thousands of years, how long before a few multinational conglomerates take over and vertically integrate entire pipelines for better efficiency, like Microsoft and Google did for internet business software? Surely those companies have overworked engineers and others doing nothing at the same time, yet still thrive?

Building (houses) is not an industry, it is essentially artisan work, some (few) of the inefficiencies could (and are) already reduced in large size projects, but such projects are rare, normally each house is different from the one built before and from the one that will be built later.

Even on relatively large projects (let's say 4 buildings with 50 apartments) you will have scale savings on costs but not great overall savings in time (time passing), that is a constant, parallelizing of course helps, so if you can build just one of them in 18-24 months, you can as well build four of them in the same 18-24 months employing a little less than 4 time the hours and equipment, so at the end you can say that it took 6 months to build one of the blocks on average, but it actually took 24 months from the beginning to the end.

It's interesting that the more advanced an economy is (and thus presumably the more access it has to machines and technologies that should speed up construction) the slower it actually constructs buildings and infrastructure.

There are a wide number of factors involved and their relative contribution is difficult to determine. Of course for starters people in advanced economies expect more of their buildings - they are built to higher standards and have more complex features which take more labor to produce. Verification that these higher standards are being met is likewise a more involved process. Advanced economies also have much less tolerance for risk - they sacrifice speed for safety both for the workers building the structures and for the end users. Additionally, workers in advanced economies tend to be less willing to go into manual labor fields and operating more advanced equipment requires more skill, requiring those who do go into the field to specialize, and thus while technology may make workers more productive this is offset by having fewer workers on any given project. Then, advanced economies tend to already be built up - you're either building in an already bustling area where extra measures must be taken to prevent disruption, or you're building in an area that was passed over for previous construction, likely for good reason. And finally, advanced economies tend to have more small stakeholders who have more influence - citizens have the means and motivation to raise objections to proposed projects and it's difficult to grease palms to bypass oversight.

Prefabrication can help - work can be parallelized, maintaining standards is less onerous, and it causes on site construction to be less disrupting. Unfortunately the larger the structure the harder this approach is - you need more capital investment for the production facilities, there are fewer customers you can sell to, and the engineering of structures which can both adequately serve their intended purpose and be transported economically becomes more challenging.

More fundamentally, everyone wants things to be better, faster, and cheaper, but you can at most pick two, and it is very difficult to get people to agree to making things worse or more expensive.

Having worked in a couple of those so called advanced economies, I would say the following are the main reasons:

1) subcontractor scheduling. A plumber needs to wait for the tiler to finish and the tiler needs to wait for the dryliner to finish. Multiple companies with multiple sites and multiple builders have to organise between themselves for this to happen. There are almost always delays

2) Poor management. Construction, is still often a boys club,where connections may matter more than skills, which leads to absolute planks running some sites.

3) short-termism amongst builders. Very few take their work super seriously, try to ensure it's done well, etc. More often than not, it's 'crew it, I ain't gonna live here' logic.

4) external factors: building in cities add lots of pressure on material delivery times, some major job planning, allowed noise hours and etc. In short, nobody likes a building site next door.

5) Reinventing wheel. Apart from high end, first time ever, engineering projects, majority of building are copy paste kind of thing. Principles are well known, however somehow almost each building ends up with a ton of idiotic little problems that compound very quickly.

I used to work in construction some years ago.

My wife constructed buildings in Asia, lol.

The fast ones you see on TikTok were like IBS (Industrialized Building System). The building was prefabricated, the groundwork was done, and the video starts recording as they transport and connect the parts.

Generally it would take about 2 years.

Piling and building the foundation is the bulk of the schedule. This is much harder in dense urban areas where it has to be done carefully.

Then you have all the other pieces - design, manpower, parts, machinery, bureaucracy, tests, redoing failed tests. Then your services like machinery, electronics, plumbing, facades, cleaning up, QA and defect fixing.

High safety projects often go faster because it's accidents that really mess up the schedule. A single death can end up causing months of delays or a hefty "fine".

If you already have a generic design or simple, non clever brutalist design, it goes much, much faster and cheaper.

That does sound like traversing a minefield.

> If you already have a generic design or simple, non clever brutalist design, it goes much, much faster and cheaper.

Any reason why governments don't force this strategy right now to solve the housing shortage. I believe they did, post-World War II?

In the US, at least, the government has been slow to acknowledge the root of the housing crisis. While simpler designs do build faster, the main impediment is municipal-level zoning controls that prevent the construction of denser housing. These codes often insist on non-brutalism, insomuch as they mandate certain materials, setbacks from the lot line, and other aesthetic intangibles, but their main purpose is to appease residents (voters) who generally wish to impede more people from moving to whee they currently live.

They do it for low cost housing here, and certain buildings like clinics. I was surprised the first time I went to a gov clinic in another town; the layout and size were exactly the same. Turns out they were all built from the same template.

You mean once the paper work is all done? You need to do excavation, pouring concrete, waiting for concrete to settle down, repeat for each floor. You need materials, workforce, etc. In my country (EU based) there is a large shortage of construction workers and there are no big companies that can take on such projects with all of their own workforce. A lot of work is outsourced or contracted. And if you have one part of the work depending on another then you just need to wait. Like for iron grids to come across the ocean.

Thanks for sharing, you seem to know the industry and the process quite well.

From a web technologist point of view, these problems are mainly related to people, politics and planning. Those things go wrong in software project as well. Of course these problems are actually the hardest problems in collaboration over time and dealing with complexity.

However software is a relatively young industry. Humankind have been constructing buildings thousands over years. Certainly, requirements and thus complexity has increased a thousandfold as well, but surely there should be enough literature on the Do's and Don'ts by now. Also the When's and How's. So why does it feel like we're still constructing housing like in the early 1900's?

I'm not directly involved in building and construction but I have friends that are.

I think that shortage of labor and supply chain issues are the biggest reasons. The demand has increased by larger scale than the number of people able to do the job.

As mentioned in another comment, red tape, regulations and general bureaucracy take a long time in addition to the construction process.

For the latter part, 3D printing might become an interesting option, see e.g. this example: https://www.gira.com/uk/en/inspirations/references/3d-house-...

That (3D-printing houses) is a non-solution or a solution to another problem.

When building a house, the actual structure (walls/beams/decks) is very, very fast to build, and if shorter times are needed, pre-fabrication is an already tested and working solution.

What takes time is before:

- site preparation

- excavations

- cableworls, pipes, etc.

- foundations

and after the naked structure is built:

- internal walls

- electric/hydrulic/etc. plants

- floors, pavement

- bathrooms and their fittings

- decoration/painting

- insulation/roof/waterproofing

- tests (if needed), etc.

Because it's a linear process, you can't do many things at the same time as you can with a car, for example.

True, but it is somewhat more complicated than that, the process in general is linear but you want to keep your workers occupied and not waiting for something, especially the specialist- drywalls can be built, the electrician can start working and plumbers connect things as soon as the first floor is up, but they need to bring equipment and workers to the site so they are usually called a little late to be more efficient and work continuously.

But generally speaking a building project gantt chart is relatively flat.

Also (most) car factories have a roof so aren't affected by the weather.

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