Constructional design and cost estimates

or: questions architects can’t really answer, but why you should totally hire one.

When you’re thinking about starting a building project of any kind, two standard questions are: “Will it stand up?” and “Can I afford this?” Unfortunately, for an architect, these questions can be difficult to answer. In our projects, we can give rough estimates, but we rely on professionals to help us with detailed projections.

A cost estimate

A while ago I was asked by someone what it would cost to build a new set of stairs. The information that I had to go on was that it concerned an existing attic ladder that was to be replaced by proper stairs. The hole for the current ladder would need to be plugged and new stairs would have to be added elsewhere. The floor was made of concrete and the floor height was about 2.6m (8.5ft). The new stairs had to be made of wood, with one corner.

My first reaction was along the lines of: it depends on the kind of stairs you want to build. But I asked a professional building cost estimator and he replied in about an hour with the following information:

Demolishing stairs and sealing the hole: €500
Painting the ceiling: €200
Making the new hole: €2000
New pinewood stairs: €1200
New hardwood stairs: €2500
Placing the stairs: €800
Painting: €500

Of course, these are also rough estimates, but much more detailed than what I would be able to offer on my own.

If you have a question about costs, the best thing to do is to get in touch with a cost estimator for larger projects, or just ask a contractor for a quote directly.

A construction estimate

Another time, someone else asked me about a hobby of theirs. They had recently bought an apartment, which was built in 1988, and they wanted to know if they could store some material. It was about 600kg that would occupy about 1.4m². The floor in question was the ground floor, below which was a parking garage and above which were three more floors. The load bearing walls were 150mm reinforced concrete.

For me, this was not enough information to go on. I asked someone I know from university, who’s in the construction design business. She said:

If I had to estimate, the total weight of the floor, including safety factors, is already about 25.86kN/m² and about 5.80kN/m² would be added to that. That’s an increase of over 25% and I’m pretty sure they didn’t reinforce the floor to take those kinds of loads.

So to be safe, I advised this person not to try it out. If you really want to know something about the construction of a building that you live in, the best thing to do is most likely to go to your local city archives and get the drawings for your building. Especially for newer buildings, there should be plenty of information to use. Getting a construction estimate for a simple job, like an addition, can be as cheap as a few hundred euros or dollars.

How can architects help with these kinds of questions?

Even though these are not the kinds of questions that architects normally deal with, we can often make informed guesstimates that would tell you something is or is not possible. But more importantly than that, these kinds of questions are often part of a larger project. For instance, the stairs could be part of a house renovation. In such a situation, it is never a bad idea to hire an architect. We regularly take care that technical details involving construction are taken into account, and we are able to work towards a budget.

So if you are considering a building project and don’t want to deal with cost estimates or constructional design yourself, definitely consider hiring an architect!

cover photo: Samuel Zeller

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