Steel decks are an efficient way to create floors or ceilings – using long, ribbed steel panels (usually galvanized, to avoid any corrosion) that span between two beams. The panels are usually up to 6m long.
They often are used in a “hybrid” way, combined with a relatively concrete layer on top. The concrete then provides thermal mass and acoustic insulation – it’s just a clean, fast and efficient alternative for “normal” concrete floors.
Steel deck is a smart building system:
faster than normal concrete slabs, as no forms are necessary
lighter than normal concrete slabs
can immediately take some load and provide shelter
can be combined with other building systems
can use concrete for thermal mass or insulation
clean underside – some like to leave it exposed for modern interiors
Limitations of steel deck construction
although simple, may need specialized labor
needs other building systems for thermal mass, sound insulation, thermal insulation
Traditional steel frame construction uses thick and strong posts and beams (usually with I- or H-shapes) to create the structure of the building.
It is extremely strong for its weight and resists very well to traction. Thus it allows for spectacular cantilevered constructions. Building is very fast but requires cranes and (usually) welders.
However, steel by itself is very bad for insulation. So it must be combined with other materials like SIPS panels for the hull of the building.
Steel frame is often associated with large buildings, but has been used for residential buildings since the 50’s – starting with notorious mid-century modernists and the famous “case study houses”.
Some like the honesty of the material and like to keep it visible in the house, while others hide the posts and beams inside the walls and floors.
Steel frame is a smart building system:
extremely strong for its weight
allows for large overhangs and cantilevers
can be prefabricated
can be combined with almost any other building material for the hull
Limitations of Steel Frame
requires cranes and specialized labor
conducts heat/cold to the inside if not insulated
will contract/expand at different rates than other materials when the temperature changes, so precautions must be taken to avoid cracks (or make sure the steel frame is protected inside a well-insulated hull)
limited flexibility to make manual adaptations on-site
Instead of ink, 3D printers for construction deposit building materials, like wet concrete, bricks or even wooden pieces, using a print head or nozzle that can move in 3 dimensions.
The whole structure of a house can be printed in hours or days. Hardly any labour is involved, so the cost is limited to the materials cost – plus, of course, the costs for transporting and using the printer.
Many news articles mention only the cost of the raw materials, or even the “expected” cost of materials. These can be as low as 44-5000, but that’s a bit misleading. As long as most other parts of the house need to be built traditionally (foundation, windows, roofs, plumbing…) 3D printing will only reduce the cost of the structure.
3D printed building is smart
Very fast to build structure
Low labour cost
Limitations of 3d construction
So far, only builds the shell
Surfaces can be hard to finish, or insulate, requiring more labour and materials in the rest of the building
Steel is strong and resists extremely well to traction; that’s why you see it anywhere from the Golden Gate Bridge to the Eiffel Tower.
That’s why it’s often used to create the structure of a house – the “bones” that keep it standing; while other, more insulating, materials are used for the walls.
This can be done with either just a few, heavy beams and posts – then it’s called “steel frame”; or with a larger “grid” of much thinner profiles, who work together to create a network structure.
This is called light steel frame; it’s logic is comparable to the traditional wood framing used in the USA and Australia.
Although it resembles the profiles often used for drywall, a LSF profile is thicker and stronger and calculated to bear much larger loads.
These days, more and more light steel frames are pre-fabricated (often robotically!) in a factory. Frames can be produced for entire walls and floors, with openings for windows and doors already built in.
Finishing panels then are easily screwed on both sides of the panels – from fibre concrete to plasterboard – and the result is fast, cheap construction.
Light Steel Frame is Smart
easy to assemble,
light, so little foundation is necessary
can be pre-built in factories
little or no waste
works with any kind of finish
Limitations of LSF
like most “light” building systems, by default it has little sound proofing. This cán be compensated by adding insulation or double skins of plasterboard/fibreboard etc.
by default, has little thermal insulation or thermall mass, so insulation and mass must be added where necessary
Like a sandwich you’d eat, sandwich panels are made by putting a filling (usually insulation) between two “sandwich” panels, often some kind of metal.
Often one of the two sheets is ribbed or “corrugated” in a shape that makes the panels stiffer. Being light ánd stiff, they can easily cover large spaces which makes them quite popular as a roof system.
Because most of them contain insulation material inside the sandwich, they are also known as insulated sandwich panels.
Some – less strong and non-structural – panels are also used to build cooling rooms, labs, temporary offices or garages.
Although they may look deceivingly simple, insulated sandwich panels do several great jobs: they offer structure, protection, waterproofing and insulation in one single, light and easy to place material.
Sandwich panels are a smart building system
very light and stiff, makes them easy and fast to install
provide good thermal insulation
large range of colors, some of which reflect the sun and minimize heat transfer
all-in-one system; even an internal finish is sometimes not necessary
Limitations of sandwich panels
you must buy quality panels; if not, under extreme heat, the outer skin can come loose from the filling (“delaminate”)
due to the lack of mass, they have limited sound insulation
you can not just “drill through” them without precautions to maintain waterproofing
Traditionally, concrete was cast on-site, using rough molds or “forms” that can be used only a few times or (even just once). The concrete is then poured in or on the forms, using heavy concrete delivery trucks and pumps.
Yet in factory conditions, concrete panels can be cast with much more precision.
The concrete can be mixed just-in-time; under perfect conditions, and in smooth molds with vibrator tables so no air bubbles are trapped inside the concrete.
As a result, panels that are cast in factories are smoother, stronger and more precise. They are called “pre”-cast because they are made befóre they are going to the build site.
Transporting pre-cast concrete panels and putting them in place requires heavy transport and cranes. But bear in mind that otherwise the same amount of concrete (plus molds) had to be transported as well.
The factory conditions allow for the concrete panels to be slightly thinner than they would be if produced on site. And insulation material can be sandwiched inside the panels as well, so the panels offer
Pre-cast concrete panels are smart:
smooth, quality concrete, cast to precise measures
can be esthetically nice enough to leave unfinished
can include insulation in one go
quick to install, a house goes up in one or two weeks
The limitations of pre-cast concrete panels?
heavy so may require more foundations
limits to dimensions because of transport and mold limitations
the insulation is usually sandwiched inside; where ideally it should be on the outside
the concrete panel exposed to the sun acts as a heat storage
you’ll need to drill to hang up anything on the walls
installations (electricity, plumbing) usually have to be added inside an additional inner wall layer (like plasterboard on studs)
Traditionally, concrete was poured into wooden forms, handmade on-site, which are discarded a few weeks later, when the concrete has cured. Others use metal forms, that can be used a couple of times.
ICF forms are made of an insulating material, like EPS, that will remain a part of the construction once the concrete has set. This way, one saves on labour ánd
They usually look like very large and light Lego bricks. This makes them extremely easy to stack on top of each other, and an option for self builders.
Most ICF forms have plastic connectors between their two outer walls. These connectors make it easy to put steel reinforcement (rebar) where needed.
They also make it possible to attach finishes by simply screwing them into the plastic connectors.
ICF insulated concrete forms are smart because:
they’re very light to work with, and easy to install
they do not have to be dismounted or discarded
they provide thermal insulation in one go
they result in extremely strong walls, thanks to the concrete core
great thermal and acoustical comfort
monolithic system without cold bridges
The limitations of ICF
the concrete core still makes this a heavy system, requiring sturdy foundations
the concrete core makes it very difficult to modify walls later
most walls are relatively thick, which may cost you internal space
it takes a little planning to hang heavy objects like kitchen cabinets
while easy to finish with “dry” materials (like plasterboard, fibre board etc.) that are screwed on the ICF’s connectors, it’s a bit more difficult to finish with “wet” materials like rendering and plastering
the builder better have a little experience with ICF, because once the concrete is poured, corrections are very difficult. If the ICF isn’t straight or gets displaced while pouring, walls may end up crooked
ICF is interesting for self builders and will give great comfort.
You may want to consider to internal walls in other, thinner systems
Consider lighter systems like SIPs to avoid foundation costs, especially on sloping land or weak soils
Normal concrete is like an artificial rock: the “cement” in concrete glues together different sizes of particles – from sand to pebbles – in a chemical reaction. It’s very good under compression, but weak when put under tension (that’s why it’s reinforced with steel rebar).
But it’s also very heavy – at 2.5 tonnes per cubic meter! That makes concrete construction so heavy that heavy foundations become necessary. (And if the foundation itself is made from concrete, the problem just feeds itself!)
Aerated Concrete is made adding a chemical like magnesium that creates millions of tiny bubbles inside the concrete. As a result, it is many times lighter ánd it is quite insulating. And it’s also known as cellular concrete, or in Europe, by the brand name Ytong who pioneered it.
The curing can be increased by a process that combines heating and humidity (“autoclave”) – hence the term “AAC” for aerated autoclaved concrete.
Unfortunately, the air bubbles inside make AAC relatively brittle – and often lots of material gets damaged in transport and during building.
Some qualities can still be structural – i.e. they can hold up a house without the need for a separate steel or concrete structure – but check this carefully and use an engineer to make sure that the AAC walls do not get any point loads that may just be too much for them!
Aerated concrete is available as blocks and panels.
AAC blocks are lighter, larger and easier to install than normal bricks or concrete blocks.
AAC panels often have rebar reinforcements to compensate for their brittleness, which makes them viable products for floors and ceilings.
The smoothness of many AAC blocks makes applying “wet” finishes like plastering relatively difficult – you’ll need very experienced craftsmen to avoid cracks in the plastering.
Is AAC a smart building solution?
it’s light and easy to work with
it thermally insulates better than concrete or brick
What are the limitations of AAC?
brittle, causing above average of material loss
harder to finish with “wet” finishes like plastering
Do you know the Eskimo’s “Igloos”? Geodetic domes are part of a “ball” shaped surface.
The ball shape is the most “efficient” shape in nature: it contains maximum inside space for a minimum outside surface.
Of course, ball-shaped homes are not easy to build (or furnish). But they cán be built with a limited number of different parts, usually forming triangles, pentagons or hexagons. While hundreds of parts may be necessary, you often need only 5 or 6 different parts!
Another advantage is that geodetic domes can take a lot of pressure (wind, snow) with a relatively light structure. Pressures from one side are transferred out over the dozens of ribs, and of course the round shape helps the wind flow around it rather than hit it frontally.
Are geodetic domes smart?
creates shelter with a minimum of structure
can be made with transparent skins
can be made with a limited number of different parts
What are limitations of geodetic domes?
not easy to furnish, low ceiling height on the sides