I need to build a ship’s ladder to access a loft, and am looking for specs as to standard pitches and rise between treads. I’m envisioning it with three stringers, with the treads offset from one side to the other (one tread would run from the left side stringer to middle one,the next one from the right side stringer to the middle, if that makes any sense)
Thanks.
Replies
I don't know if the answers to your specific questions are in these threads, but if not, you'll probably find pointers to the answers.
http://forums.taunton.com/tp-breaktime/messages/?msg=6906.1
http://forums.taunton.com/tp-breaktime/messages/?msg=10857.1
http://forums.taunton.com/tp-breaktime/messages/?msg=13818.1
http://forums.taunton.com/tp-breaktime/messages/?msg=18526.1
http://forums.taunton.com/tp-breaktime/messages/?msg=20965.1
http://forums.taunton.com/tp-breaktime/messages/?msg=23820.1
http://forums.taunton.com/tp-breaktime/messages/?msg=25282.1
http://forums.taunton.com/tp-breaktime/messages/?msg=35222.1
Dan,
I've seen the type (alternating steps) that you want to build, and I personally don't like them...too awkward. An alternative is to build a regular, double stringer ladder stair with the stringer being grooved or "housed" rather than cut; so as to retain it's strength.
Stringers can be 2x8s ( even 2X6s) and grooved ( routed dadoes) to accept treads. For added security, drive some long, ring-shank nails or screws through the sides of the stringer and into the treads...or...run 1/2 inch dia, bolted, all-thread underneath treads in a few locations to keep stringer tight.
As for run and rise...no set standard for this type. Best to temporarily position 2x (stringer) stock material into loft opening area. Position stringer with as much "lean" as you want or need. Lay a straightedge on floor next to bottom of stringer and mark for your floor cut-line. Cut off stringer at this angle and reposition in loft opening. Temporarily tack stringer in place at the top. You can let stringer top run long so as to act as handrail when entering top of loft ...or you can cut stringer near top and attach stringer to loft bulkhead. If attaching stringer to bulkhead, use straightedge and mark desired angle as before, then...cut and re-tack in place.
Once one of the stringers have been cut and fitted for the intending opening and temporarily tacked, use a story pole to transfer riser height locations to stringer. Use a 1X4 as a story pole. Total length of story pole should be same as height measured from ground floor to loft floor. Using this measurement, mark off story pole in equal segments. You determine segments ( example...90 inch total height...stair risers could be spaced 11-1/4 inches apart for 8 treads...or 10 inches apart for 9 treads...or 9 inches apart for 10 treads..etc....you determine what riser height you feel comfortable with when climbing.)
Each segment equals a stair tread location. Set story pole up (vertically) in place next to stringer and tranfer these marks to the stringer. Make any adjustments necessary to accomodate tread thickness and once satified, proceed to cut stringer dadoes. Once finished, use this stringer as pattern for the other stringer.
An alternative option to cuting dadoes would be to simply attach wood or metal cleats to the stringers, and secure your treads to these cleats.
Hope this didn't confuse you too much. A book titled BASIC STAIRBUILDING by Scott Schuttner does a better job of detailing what I just tried to explain. The book is by Taunton. Building ladder stairs is covered in its entirety in the very last chapter of this book. Photo pics are B&W but very informative.
LOL.
Davo
I agree with Davo about the alternating tread, but of course it's your choice.
I'm actually doing the same thing in the cabin I'm presently building. I want the loft access to take up as least room as possible so I am designing it like an old barn ladder. The treads will square mortice into the side rail and be visually pinned like a piece of Stickley furniture.
You can lay out the stair the same as any other........just change the numbers to suit your need and forget code I don't think any inspector would pass on it anyway.
I have an ex-bil who used something way cool..submarine stairs. All Aluminum, with foot pads heliarced from the sides, open in the center..The first journey is kinda odd, but like jumping hurdles, start off on the proper foot (not always the "right" foot, LOL) and once ya get the hang of it, you can really fly..I almost never take stairs "one step at a time" but skip every other one..on Sub stairs/ladder..they are far enough apart that is not needed.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
Why are they open in the center?
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
I Dunno, but they were way cool..I just spent a half hour googling for a pic, can't find any. He may have made them himself..the treads were in the shape of a BIG shoe print.
Being an EX BIL, I don't think he'd send me a pic...messy divorce and all that..
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
Slightly off topic I have been replacing lights and transformers on some track lighting above some library shelves. Access is via a rolling library ladder.
The thing goes STRAIGHT up about 6ft and then breaks and angles toward the walls.
That thing is very weird climbing until you get to the break. Keep feeling like you are going to fall off.
yikes..sounds so.
Just found the alternating tread ladders are 68 degree climb'with 9'' treads..fwiw
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
There was an article/picture of these in FHB not that long ago. Use the online index and see if you can find it.....
Then again, I once stayed in a ski condo with one of these. Tough after a day of skiing when your legs are tired, even tougher after the evening's partying.
Steve
I remember an article in FHB in the past 2-3 years about a house built in old Mexico. They built an offset-step ladder for access to the rooftop cistern.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
AFAIK, there are no 'standard' specs for a ship's ladder; each is designed to fit the requirements of the ship in question. Generally, overall angle is between 70 and 80 degrees (can be less steep if space is available but it often isn't) and rise is 12 inches or close to it.
Two immutable aspects of ship's ladder design are non-skid tread surface and double hand rails. The overall width at the handrails rarely exceeds about 24 inches, enabling a seaman to descend a nearly vertical ladder facing forward--but more by sliding on his hands than anything else, using the treads very lightly, sort of like stepping stones....
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Dan,
The founder of this company invented the alternating tread stair, but I think the patent is expired. Here's some info:
http://www.lapeyrestair.com/
Click on "alternating tread stair."
Billy