Loretto Staircase
Summary: The Loretto Staircase is surrounded by an air of mystery - who built it and why is it still standing. But the Loretto Chapel Miracle Staircase is subject to the same laws of physics as any staircase or circular staircase.
DEAR TIM: I recently was vacationing in Santa Fe, NM, and saw the Loretto Chapel staircase. It’s a beautiful wooden circular staircase thought to be constructed between 1877 and 1881 by an unknown carpenter. There is no center support and nothing seems to be holding up this staircase but the will of God, or so promulgates the private owners of this building. Is the miraculous staircase in the Loretto Chapel just that, or is there a scientific explanation for why it’s not a pile of splinters on the chapel floor? Michele B., Minneapolis, MN
DEAR MICHELE: I’ve also seen the Loretto Chapel spiral staircase in person. It’s a magnificent work of art, that humbles me as a master carpenter. To create a staircase today like this using an assortment of power tools and modern hand tools would be a feat. It’s mind boggling to think about constructing such a marvel with crude hand tools, no electricity and minimal resources.
But that doesn’t make it impossible, nor less complex than many other building and engineering masterpieces that are clearly visible in old structures around the world. The current private owners of the Loretto Chapel state on their website:
“The stairway confounds architects, engineers and master craftsmen. It makes over two complete 360-degree turns, stands 20 feet tall and has no center support. It rests solely on its base and against the choir loft. The risers of the 33 steps are all of the same height. Made of an apparently extinct wood species, it was constructed with only square wooden pegs without glue or nails.”
This will all make sense if you allow me to explain to you the basic structural components in a house. I’m convinced that once you understand this, you’ll see that the talented carpenter who built the Loretto Chapel miracle staircase just happened to know what I and a few others know about beams.
If you live in a house with a wood-floor system, the floor you walk on each day supports you. It doesn’t collapse under your weight, the weight of the furniture and any guests you may have during a large party. The floor system is made up of joists and wood that covers the joists. The floor joists under your feet are beams not unlike steel I-beams in a skyscraper.
In a typical floor system, these beams or floor joists run parallel with one another on 16-inch centers. The joists are covered with plywood or other wood sheeting. The joists rest on a foundation wall or sometimes another beam that rests on a foundation wall. The weight of the entire system and anything on it is transferred to the foundation by the joists.
Imagine if you had a narrow floor, meaning just two joists and you cover these with plywood. This would be very similar to a narrow foot bridge. You could walk across it and the platform or bridge would not collapse. Let’s now drop one end of this narrow platform to the ground leaving one end up on the foundation wall. Now you have a ramp.
The normal staircase in your home is just like this, but instead of a ramp, the builder made flat steps or treads so you could climb it without slipping or sliding. A simple staircase has two beams, called stringers, and the treads of the staircase rest on these beams or are connected to them. The stair treads are no different than the wood that covers a flat floor. When the carpenter set your steps in place, the weight of the staircase was transferred to the floor below where the two stringers touch the floor.
The only difference with the staircase at the Loretto Chapel is these beams or stringers have been twisted into a helix. If you took the staircase apart and just allowed the inner and outer stringers to stand there by themselves, they would do so like the flagpole just outdoors on the plaza, even though each stringer is made up of several pieces of wood glued and pegged together. It’s that simple. It’s not a miracle at all.
This legend is being perpetuated by the owners of the chapel. They have a vested interest to make sure tourists come to see this masterpiece and that couples continue to get married in this magical building. If the owners just told you that the staircase was just a regular staircase that was resting on the floor of the chapel, you’d might not part with your cash at the entrance to the chapel.
But please understand that it’s well worth the price to see it. I say this as a very modest carpenter who stands in awe of the man or men who worked together to build the staircase in the Loretto Chapel. If you are near Santa Fe, NM, I urge you to stop by and see what can be done with simple hand tools, knowledge of physics and math, and determination.
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Comments:
Joseph Schmitz 17 Jan 2010, 14:59
I visited this chapel several years ago, and read about the history of the
sprial staircase. The building still belongs to a order of sisters and is
leased out. The stair case does not have any nails or glue to support it
and it is almost free standing.I know something about construction and
looking the construction over with its spirals and no nails, glue or
exterior supports and the time that it was built tells me that this
definatly could be a miracle. Putting it nicely, you are incorrect on your
closing statement. Miracles do happen wheither you like it or not.
JasonL 25 Jan 2010, 20:18
Engineering is engineering. Calling it a "miracle" is insulting to the
skill of those who built it. The author is correct in the regard that the
person who built this was perhaps smarter than most in his day. That is
what made others call it a miracle, simply because they could not explain
it.
JohnW 26 Jan 2010, 10:13
While a beautiful and masterful application of the constructive arts, and a
mystery as to its structural design, I would have to agree that there is no
miracle to the staircase itself. Calling something a miracle simply
because you do not understand it reveals more about the proclaimer than the
builder. If told accurately, that some guy showed up just at their time of
need, ok, attribute that to to a miracle, or serendipity, or what ever. It
is still a beautiful bit of structural art.
JoelC 29 Jan 2010, 00:21
I can see both points of view and by no means am I saying that I am in a
position to speak to the construction of this staircase with experience but
I do have a very good point in asking the following: If this is possible,
why is it the only one of it's kind? I have looked and been unable to find
one. The stairs look beautiful and I have seen many similar to it but they
all have a center piece. You would think that if this was possible, we
would see many more of them because it is a space saver, visually
attractive, and would save in materials considering that it does not
require nails, glue or a center peice to hold it together. I also disagree
with the statement made about it being an insult to the carpenter by saying
it is a miracle because I whoever built it has done an amazing job
regardless of how he put it together (miracle or not I don't think anyone
is doubting the talent in the carpenter). I will have to do some more
research because I am all about facts but for now, I would have to go with
Joseph on this one.
Jim Long 31 Jan 2010, 03:52
Back in the 90's a lady named Mary Cook Identified a french immigrant named
Francois-Jean Rochas as the man who built the stairway. He was a master
carpenter/woodworker who came to Santa Fe around the time that the chapel
was near completion. One of the contractors was also a French immigrant and
there is some evidence that Rochas came to Santa Fe to work for this man.
Also Rochas' 1895 obituary specifically states that he was the creator of
the "handsome staircase in Loretto Chapel." The "miracle" of the staircase
(from an engineering p.o.v. at least!) is the staircase's concealed, small
diameter stringer on the inner spiral that effectively serves as a central
pole support. The staircase is made of a type of spruce that is not native
to the area. Apparently, Rochas finished the stairway and departed before
being paid, because the Mother Superior of the chapel offered a reward to
anyone who knew who/where he was so that she could pay him for his work. It
was never claimed. A man shows up just at the time he is needed most, does
an absolutely magnificent job, then leaves without seeking reward for his
work. maybe that the true "miracle of Loretto Chapel".
Marc 02 Feb 2010, 17:37
Tim,
I certainly agree that it is an example of great design and not a miracle, but your explanation leaves one important detail out. You describe how stringers work, but your example focuses on straight stringers that carry their load to the foundation and are otherwise like a beam, trying to deflect in the middle, meaning they are in compression on the top and tension on the bottom edge. On this helix stair these forces exist as well, but there is an additional outward force that is particularly relevant on the outer stringer because it is much longer, and the dynamic loads (when people walk up or down) are much more significant. While it is still just physics, this is a much more difficult project than any straight stair. If the stair did not connect at the loft it would almost certainly collapse, but even allowing for that it is still quite a feat at a time when stresses could not be computer calculated and engineered woods could not be ordered. What I think is a miracle is that the wood stringer has the tensile strength to hold this load and still appear so elegant!
Milton Gregory Grew, AIA 03 Feb 2010, 12:17
Although very beautiful there is no real mystery to the construction of
this stair. It is basically as Tim outlines above. This kind of stair
design is called helical and there are many such that have been built. For
instance, look at these websites:
http://www.yorkspiralstair.com/Selecting/gallery.asp http://www.uniquespiralstairs.com/gallery.htm There is an article in Fine Homebuilding about a modern stairway which was based on the Loretto: http://www.finehomebuilding.com/how-to/articles/double-helix-stairs/clamps. aspx?ac=fp This is definitely not a miracle other than the God-given skill of the craftsmen that built it. Milton Gregory Grew, AIA, Architect Grew Design Inc. Woodbury, CT
Mike Parolini 07 Feb 2010, 12:09
Like many structures of the past,Iwould love to take apart to see the trade
secretes or the leap in technology at the time.Are there any drawings?Who
would not want to see the math on this.
Jim Baldwin 14 Feb 2010, 02:51
I am a professional stair builder with specific knowledge of the several
techniques used during this time period.
The outside (and concealed) supporting stringer is most likely a stack of solid timbers that are bow-sawn to the radius of the stair. These timbers simply stand on top of one another in a staggered horizontal fashion and circle all the way around to the top. They are normally held together with animal hide glue and vertical sticks. The staving-sticks are nailed around the outside. The use of pegs and wet rawhide strips would also have been typical. Of course you can't see any of this because of the veneered face or kerfed covering boards. The totally enclosed underside of the stair also conceals the structure from view. With this kind of stair, the outside stringer carries nearly all the live and static loads. There may also be a middle stringer constructed in the same manner but the inside stringer is usually just a light, staved veneer. A stairway like this is able to stand completely on it's own and needs no external load-bearing support whatsoever. (And no, it's not hanging on to either the top floor or the walls, just resting against them.) Anyway, the carpenter who built this staircase was positively a professional "stair builder" (and not just a man on a mule). He was however not a professional "handrailer". (The completed balustrade was added some years later) That is usually a separate job or skill within the trade and represents at least 50% or more of the total job. The reason he probably left without being paid is that this stairway is quite unusable without a balustrade. Can you image ascending this stair without a guardrail of any kind? What makes this stairway unique is that it makes two complete revolutions and stands twice as tall as a normal spiral stair. Anyway, the stairway itself is no miracle but definitely an answer to faithful prayers and a testament to the knowledge and skills of a single carpenter. The real miracle however may be in the fact that it's still standing. Rawhide and Hide-glue can degrade and decompose over time and old square iron nails turn to rust. Termites within the timbers might also be expected. The underside of this stair should be opened up and everything thoroughly inspected by a qualified professional. No one should ever be allowed to use this old stair (not even to clean it) until it is certified to be structurally sound and safe.
Darren Bezanson 25 Feb 2010, 13:46
Hello to all visiting this blog on the staircase at Loretto Chapel. What I
find interesting from all comments listed is that we look at this by
today's standards and what we know today about building. In the time this
stair case was constructed, many buliding techniques had not been polished
or considered. Building codes were not as considered. The builder who
contructed these steps filled a need that was present and left without a
thanks. We often do things out of faith and consideration of others. We can
pull apart why it is the way it is, but why. Those who consider it a
miracle were blessed and live by that faith. those who consider it not a
miracle, that is your faith in what was constructed and feel someone needs
credit. I am a man of faith and feel, God indeed answered the Nuns prayers
by sending a humble carpenter to filled a need for the faithful prayers of
the Nuns. It was a miracle to them, and still is, because of their faith.
For me I agree with both sides, a gifted carpenter who wanted to fill a
need came and blessed the Nuns with his skills.
have a blessed day, Darren View all comments |
