Architecture can’t exist on a page it must
be built and transforming our drawings and tiny cardboard models into physical reality
means choosing materials to represent abstract ideas. Now, I find this part of the design process
so interesting because I really view it as a form of storytelling. By simply varying a building’s materials
we can create something entirely different. Now, although this is part four of the course,
I’ve actually been thinking about the architectural material palette for our case study project
since the first time I visited the site. Now, I always pull together potential materials
I want to use during the early design phases because, for me, they help determine the building’s
form and they shape the narrative and experience I want the design to convey. Material decisions - for me – tend to arise
from the design concept, strengthening and supporting it and the process requires making
many choices, about form, about scale, about color and texture, about construction, water-tightness
and durability, about installation and finishing, and of course cost. Understanding the properties and uses of building
materials is as much the duty of an architect as understanding good proportions or physics. So, let’s get into the five categories architects
consider when selecting materials for our architecture. Every material will have characteristics present
in each category, but will also have a more dominant place in one or another. In this way, the categories overlap and it’s
ultimately up to the designer – the architect – to decide how to prioritize the criteria
that matter most to the design. With each one I’ll present the principle
then describe how our material selections were informed by it. The first, and most obvious are a material’s
physical characteristics. This includes its weight, porosity, density,
strength, acoustical properties, its resistance to weathering, its structural properties and
this extends to how it will be supported or fastened and how it impacts the physical performance
of a building. Then there’s the ever-important physical
appearance or aesthetics of a material: color, texture, shape, how it patinas, is it glossy,
or matte or smooth? And finally, the physical characteristics
include maintenance concerns as well; is it easy or difficult to keep a material clean
or in working order for example? Now, many architects quite naturally begin
with the physical characteristics of a material. What are the aesthetic goals of the project? For our project, I’ll start by referring
back to the concept now we’ve been designing an encampment by the sea that sits at the
edge of a forest and closely follows the topography. So, I’ve drawn from the building’s wooded
context to begin choosing the material palette. To tie the architecture to the surrounding
site and to defer to the landscape - the forest and the water - it was important to me that
the building recede as much as possible. I wanted the building to be discovered almost
like a shadow in the woods. Now, as architects we have only a few physical
elements to accomplish this: there’s the walls, which also include doors and windows,
there’s columns or exposed structure, there are roof surfaces either flat or pitched,
and then there’s horizontal surfaces – things like steps, decks and walkways. For the walls, I chose an exterior siding
of dark stained cedar shingles because dark colors tend to recede. I initially preferred an even darker Shou-Sugi
ban siding, but the cost and the hue were limiting factors for my client. So, we agreed on a dark matte green stain
selected among many different hues as a balance between the bark and foliage of the conifer
forest. Shingles are nice because they create a natural
texture and shadow to the wall surface. So, you can already hopefully see how I’ve
prioritized the appearance characteristics of the material as being more important than
the other physical concerns. Now, that’s not to say I don’t care about
porosity or density, but they’re secondary or maybe even tertiary. Wood will wet and dry quickly if I build it
in such a way that there’s a ventilated rain-screen behind it. Cedar is naturally rot resistant and factory
finishing the shingles provides a long finish warranty period so we’re also ticking the
maintenance checkbox here too. If – as we’ll get to soon – cost were
the most important I’d probably choose materials which wouldn’t require any finish. That approach, however, might not blend in
to the forest as well. Along with the siding, the walls are comprised
of windows and doors too. For these we’re using an aluminum clad window. Using metal clad windows limits maintenance
over the long term, especially here on the coast. We could’ve chosen all wood windows and
painted or stained them, but our priority here was to minimize maintenance on a particularly
expensive to maintain building system. We chose black from among their standard color
options for the frames because it adds punch to the openings, kind of like eye-liner and
glass in exterior walls is perceived as black during the day so it contributes to this receding
effect we were after. It also means that during the day the entire
wall surface will be viewed as one unit, rather than calling attention to the window and door
frames. Hardware for these is all stainless steel
so a light gray color mainly chosen for its resistance to corrosion. Trim at the roof, soffit and around the openings
was designed to be as low profile as possible and all are stained to match the shingles. All concrete was left unfinished and exposed
as we’re insulating to the interior face. Now, this is a concept called truth in material. For further reading about this idea be sure
to check out the Arts and Crafts movement of the late 19th and early 20th century as
well as the modern movement, both were exploring and developing the truth to material concept:
using a material for its inherent physical properties and exposing it for its natural
beauty rather than concealing it. Concrete has superior compressive strength
but rather poor tensile strength so a truth in material approach would use concrete in
locations of a structure subject to high compressive loads. This is why you see it used often in foundations. Steel, by contrast, is excellent in tension
making it ideal for long beams which deflect under load and tensile forces. Combining the two, we have reinforced concrete
– concrete with embedded steel rebar - which marries the best properties of both materials
into one. Now, there are certainly many more approaches
to selecting materials, but this one in particular resonates with me personally as the most honest
and forthright strategy. The site retaining walls were poured in place
concrete with a board-formed finish. Here again, we’re recalling the forest environment,
using the horizontal lines to reference the siding, to reach out into the landscape and
the wood grain is an abstract nod to the trees of the forest. I also like that the board forming reveals
the process of making - how concrete transforms from a plastic material when poured to a weather-resistant
solid mass when cured. The horizontal coursing matches the siding
and the dull gray conforms to the muted palette of the building as well as the granite outcroppings
and the gray of the nearby ocean. Let’s move on to the second category we
use for material selection: context. Now, context can mean many different things. It can be a material’s physical context
– like its exposure, will it be used inside or out? Will be exposed to water and sun, or to wind
or corrosive or hazardous materials? Context can also refer to a material’s proximity
to other materials or nearby structures that use a common architectural language or even
a historical context, clay tile or brick is a good example. It can also mean a material’s cultural context,
local building traditions or specific meanings. And then there’s also the functional context
of a material, for example it would be difficult to justify constructing a prison entirely
out of glass, right? Our project has many different contextual
meanings to draw from. I mentioned the forest which has informed
our decision to choose a dark siding, but our materials also have a variety of interior
and exterior exposures and a precise location near the salt water. Equally, our interior materials will be adjacent
and experienced in conjunction with the exterior materials. So, lots to talk about here. Context is intimately linked to the concept
of contrast and it’s one the most important things to understand with respect to choosing
materials. It’s what distinguishes one thing from another
and we use it to make sense of our world. Gray concrete feels cooler and wood feels
warmer when these materials are next to each other. Similarly, textured surfaces appear more textured
when placed near smooth surfaces. We can use this in our architecture to emphasize
our ideas. Hard, soft, warm, cool, light, dark. Heavy, slight. Here we’re using both context and contrast
to great effect when we move to the interior material selections. The rough bark of the exterior siding gives
way to a smoother, warmer toned interior. For the floors in the main living spaces I
selected a local red birch in a five-inch wide plank. This sets a warm plinth which grounds the
space. If the exterior is the bark of the tree, the
interior contrasts that by acting like the heartwood, warm and welcoming. At night, the dark shadow of the building
virtually disappears into the forest and the warm wood is like a lantern or a tent in the
forest lit up like a beacon. The entry areas and connectors will receive
a gray porcelain tile – a highly durable stone alternative and a result of its functional
context hosting soiled foot traffic. We had hoped to use natural stone or poured
concrete, but the tones of the local stone and concrete mix didn’t align with our client’s
taste. So, this was a compromise. We opted for the porcelain for its low relative
cost, its durability and its low environmental impact as its made primarily from recycled
material. The cleft finish is another play in contrast
against the nearby satin of the oiled wood floor. To help the view to take prominence inside,
we’re painting the window frames black rather than matching the adjacent wall surface. The idea is again to downplay the window frames,
to dissolve them. Walls and ceilings are primarily painted gypsum
wallboard and this too was done to downplay their presence. Inside, we wanted the spaces to be about the
warm floors and the views to the site. Alright the next category is a material’s
experiential qualities. Materials may seem hard or soft based on our
perception. For example metals are often perceived as
hard even when their physical properties might suggest otherwise. Aluminum is a soft metal, but it’s often
perceived as hard. This is because of personal bias or associations
with certain materials. Now, these emotional connections shouldn’t
be underestimated. I once had a client who disliked my suggestion
for a metal roof as she had grown up living beneath a metal roof and associated that with
a difficult time in her life – a time she’d rather forget. In part, the experiential qualities informed
our roof material choice. Standing seam metal has this crisp, taut look
that reminds me of a Maine woods camp. So here we’re relying on what the material
connotes or signifies. But the roof is a great example of a choice
where many factors influenced our decision. I wanted to maintain the monochromatic exterior
color palette and so I chose a zinc-colored painted aluminum to coordinate with the wall
color. We could’ve selected zinc or a lead-coated
copper - truth in material - but both were cost prohibitive and the rainwater run-off
from zinc reacts with cedar in unpredictable ways. Metal balances a streamlined installation
cost – because big panels go up quickly, and a low life-cycle maintenance cost. Another consideration here on the coast, we
have to be really careful about which metals we use in the corrosive salt air. For the roof, I chose PAC-Clad’s painted
aluminum metal roofing system which carries a 30-year coastal warranty. Now, all these factors play into the final
decision, but one is always more dominant than another. Certainly, the experiential qualities of materials
and a building’s interior design are codependent. The money we saved by using gypsum wallboard
everywhere, we allocated to purchasing machined structural tie rods and clevises. These are all exposed and fabricated from
stainless steel and they clearly express the tensile forces of the structure in the main
living space. Where the outer walls want to spread apart
under the roof load, and the tie rods hold them together in tension allowing us to vault
the ceiling and increase the volume of the main living space. Importantly, these rods convey both camping
and nautical experiential cues – cordage and rigging. Now, we’ll get into the design of the kitchen
and the baths in a future video, but briefly in the bathing spaces, the floors and shower
walls all receive the same dark gray tile we’re using at the entry and connectors
we’re mixing up the texture of the floor with a pebble tile at the bathtub and shower
rooms. The pebbles help with grip under foot and
they reference beach stones. The fixtures in the baths are gloss white
and polished chrome which contrast the rough textured floors and then we finish out the
bathing spaces with etched glass shower wall dividers which will act as sort of these bright
luminous planes in what are relatively dark bathing spaces. Moving on, we come to costs. And here we include, not only the material
costs, but acquisition costs, maintenance, shipping, and installation costs. Often new cutting edge materials will increase
labor costs due to unfamiliar installation processes. All materials have a cost and if you have
a lot of area dedicated to one material like our shingled walls for example you have to
be careful not to specify an expensive material to keep within the project budget. Or at least be cognizant of it. Shingles have been used on the coast of Maine
for a long time because they’re durable, rot resistant readily available and fairly
inexpensive. Selecting local materials is always my preference
when possible because it’s a more environmentally friendly choice. It also maximizes the local labor force’s
experience installing them. Even though the material is economical, labor
can add up quickly as they’re installed one at a time. The shingle coursing I initially specified
was four inches - meaning every three courses would equal one vertical foot, which aligned
nicely with the window and door openings. To me, this presented more of a textured face
but it also required twenty percent more shingles per square foot of wall area and that quickly
became a cost concern. This additional cost of material and labor
was significant and so we compromised to a more standard five-inch coursing. Now, this is common practice in design, we
propose ideas and then test them against a host of factors. We revise and revisit as we receive additional
information, in this case cost information. Was a twenty percent increase in the cost
of the siding justified? Was the added effect worth it? In the end, our answer was no, but perhaps
for a much smaller structure it may have been yes. Cost implications and material selections
are one of the easiest things to weigh during the design process. It’s one reason they’re the target for
cost-savings efforts along the way. But, typically, the biggest driver of cost
is the overall square footage of the project, not material cost. Even so, we’re careful here to limit the
more luxurious materials – like soapstone – to limited areas. And these are areas that we’ll be interacting
with on a daily basis, like the kitchen counters. And the fifth consideration here is related
to manufacturing. Here we’re talking about installation, acquisition,
assembly or finishing. Now, this may also apply to environmental
impacts too things like how resource intensive it is to manufacture, to mine, or procure. Life spans of materials fit in this category
too. The decking choice is a good example of something
we struggled with with respect to sourcing and environmental impact. Now, I love using the local cedar here for
decks, it’s really soft under foot and it weathers to a nice, light silvery gray which
would also mimic the horizontal plane of the nearby water nicely, but its softness is a
real liability, it affects durability. It’s significantly less expensive than a
tropical hardwood like Ipe, but doing a quick life-cycle cost analysis, we discovered we’d
have to replace it more often than a harder, longer lasting material like Ipe. The Ipe is more expensive to acquire and install,
but it will last much longer and has the same visual appearance characteristics as the cedar,
weathering to a nice silvery grey. In the end it was cheaper. We sourced ours from a managed forest to diminish
the environmental impact of it as well. So, in this case the long-term durability
trumped everything else. So, those are five general considerations
which will inform your material selection for your architecture. Remember, each of these material considerations
can be thought of democratically; that is, none is necessarily more or less important
than another. Your design should begin to suggest what materials
best represent your ideas. And it can be precious few. You want to study the work of architects like
Tadao Ando, Louis Kahn, Peter Zumthor, LeCorbusier and Aalto – and witness the depth of knowledge
and skill they deployed using a relatively limited set of building materials: wood, concrete,
glass, and brick. You can say quite a lot using a very spare
palette of materials. Now, the take-away is that the material selections
were a result of intentionally considering all aspects of the experience we wanted to
create for our client as well as the necessity of building something durable and meaningful
here in an extreme coastal environment. It has to look good and tell the right story. It has to comfort and shelter, reduce and
minimize our impact on the site and recreate - in an abstract way - the quiet of the forest
in the new place we’ve created. It’s a tall order, but by following a process
which prioritizes the most important characteristics for each part of the architecture you can
find a methodology for choosing wisely. Material selection requires you to be an observer
and student of the built world. Study buildings you admire and note how the
material qualities effect how you feel there. Now, if I’ve helped you at all with this
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