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I'm seeking advice on the best way to go about building a full scale replica of the Immovable Ladder [wikipedia], a late 17th/early 18th century wooden ladder that rests against a second story window at the Church of the Holy Sepulchre in Jerusalem and has been in place since at least 1728, unmoved since then due to the 1757 Status Quo decree from the Ottomans which stated that nothing can be moved or altered at the Church without agreement from all six Christian sects which co-govern the space.

No real reason for the build, I just need a ~7 foot ladder and figured why spent $150 on a Werner when I can have a ladder that serves as a constant reminder of a schism dividing one of the world's major religions.

The ladder is in various places described as "simple", "about 7 feet tall", and "made of Lebanese cedar", though I can't substantiate any of this myself. Below, I've posted four of the most clear photos I can find online, as well as a 1728 engraving by Franciscan Monk Elzear Horn, which represents the earliest known representation of the ladder in it's current location. Following the photos is a description of my current plan.

ladder from the front ladder close up ladder from below ladder from above 1728 engraving

First, I converted a picture of the ladder into a vector image to measure its angles and relative dimensions. It leans against the wall at a ~15 degree angle, which I understand is still considered best practice. A leaning height of 7 feet yields an acceptable rung spacing of ~14", so whoever made this ladder definitely wasn't behind on their OSHA continuing ed.

I plan to get two 8 foot cedar 2x4s for the side rails, which I will cut down to 7'3" so that the finished height of the ladder when leaning is 7 feet tall. I'll trim the top and bottom at angles so that the ladder rests stably at a 15 degree angle from the wall.

Next, I'll make five dado cuts into each 2x4 with a mitre saw for the rungs/steps, cutting about 60% deep into the wood. I can't tell from the photos if the notches which hold the steps in place go all the way through the width of the side rails; I'm inclined to stop the cut short about 1/2" of the full width of the board. I'll use 2x6 cedar for the steps, cut down to protrude ever so slightly from the front of the side rails and knocked into place with a wooden mallet. The second photo above seems to indicate that there are about 3 nails hammered through the side rails to keep each step in place. I'll sand the front edges of the steps and that should do it!

Very curious if anyone has any guidance or feedback...some things I'm wondering include:

  1. Securing the steps: is there a best practice for how deep to cut the notch into the 2x4? Assuming a nice tight fit for each step, will three 16d nails on both side of each of the 5 steps suffice to keep the ladder sturdy?
  2. Is there anything else you can determine from the photos that can help me make the replica more precise?
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    Hi, welcome to StackExchange. This is a fun Question but you're really asking more than the format ideally supports — every Question should really contain just one query, at most two. And also, 1st bullet is wholly subjective; whether you asked in a semi-tongue-in-cheek way it's of course entirely up to you (and honestly should make zero difference to the end product, assuming good practices are followed in both cases). 5th bullet, again that's entirely a personal choice (with far to many potential contributing factors for respondents to guess at). I suggest you edit down to the 3rd [contd]
    – Graphus
    Commented Dec 13, 2023 at 10:19
  • ...bullet here, then ask the 2nd as a separate Q (it's perfectly fine to ask multiple Qs about a single project). And to save you asking it and have it potentially flagged for closure as a shopping Q, I believe real cedar is available in the US but very hard to get. It may also be expensive as all get out (not least because of the thickness of stock needed for this); anyway, Googling around should answer this for you. My suspicion is that you'll be going with something else, good news is that American white oak would make a very decent alternative due to both strength & exterior durability.
    – Graphus
    Commented Dec 13, 2023 at 10:26
  • 1-1/2” actual for the treads seems too thick. Maybe adze the finished 2x6 to get that rusticated look. And have you thought about some kind of hidden threaded rod doohickey to tie the rails together top and bottom? Nails in end grain may have worked in the original application, but I’m certain they’ll disappoint in actual use. Commented Dec 13, 2023 at 13:39
  • Yeah, bullets 2 & 3 are the only reasonably answerable questions here, and #3 is hard to determine from the pictures provided, leaving #2 as the only reasonable question. For that - make good, tight mortises, sneaking up on the dimensions.
    – FreeMan
    Commented Dec 13, 2023 at 14:37
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    @AloysiusDefenestrate good question about the hidden threaded rod doohickey. Is it possible to do that with just a hand held drill? I had been considering downsizing the steps to 6x1, but maybe it's worth keeping them 6x2 to prevent splitting if I try and thread a rod through the top and bottom step. Commented Dec 13, 2023 at 19:12

1 Answer 1

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Securing the steps: is there a best practice for how deep to cut the notch into the 2x4?

An oft-used rule of thumb for cutting these grooves (housing joints) is 1/3 of the original material. This is by no means universal however.

Is there anything else you can determine from the photos that can help me make the replica more precise?

The original ladder appears to have had the housings cut far deeper than 1/3, but this may be illusory due to nosings on each tread. If present these may overlap the front of the uprights, hiding the true depth of the groove behind. It's impossible to know either way from available photos.

If there are overlapping nosings they may further hide that the ladder was built using dovetail housings (AKA sliding dovetails). Although this is highly speculative it could account for it still being in one piece if it's had zero intervention since 1757! [Regardless if this is a feature of the original, I would highly recommend it if you can swing it since it will add an untold amount of strength.]

Assuming a nice tight fit for each step, will three 16d nails on both side of each of the 5 steps suffice to keep the ladder sturdy?

This is the type of thing that should be determined empirically — test for your application with your wood, your housing depth, your glue (if any), and most importantly your nails1 and nailing technique2.

Where safety is paramount — and it most assuredly is here — I would caution not to listen to any one source, no matter how (apparently) authoritative, such as an experienced carpenter who would have decades of practical experience and presumably Knows His Stuff3.


1 Currently available nails come in numerous styles, with differences in the shaft diameter, head size, additional holding features, as well as a range of surface finishes/coatings, so there's huge variation possible here. And then there are cut nails, which may be superior in holding power to anything modern (expect their weather durability to be among the lowest however). Note that if you go with cut nails, pre-drill if building in any harder hardwood.

2 Most people nails things in basically perpendicular to the surface which is fine for many applications, but hold can be significantly improved by dovetailing some or all of the nails. Here I would at minimum nail like this / | \

3 One of the fundamental problems with expert advice is that experts can disagree on things, in fact, as the Internet has allowed us to see more clearly than ever before, they frequently do. Ergo the advice of any one of them cannot be taken as gospel....... no matter how much they want to give that impression ^_^

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  • Sliding dovetails are an excellent idea and I’m ashamed that I didn’t think of them. Also +1 to the non-parallel nailing pattern. Commented Dec 14, 2023 at 13:31

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