Replies

1. 
   Sawdaddy | Nov 30, 2007 01:12am | #1

   I don't have any layout tips, but it's called an alternating tread stair. Or sometimes alternating tread ship's ladder.

    

2. 
   splintergroupie | Nov 30, 2007 01:14am | #2

   Search "space saver stairs" for lots of different designs. Use Google Images, too.

3. 
   mike_maines | Nov 30, 2007 01:41am | #3

   I believe the rise and run are just like normal stairs--so around 8" max rise, 10" min run.  That's measured as you walk up the stairs.  From one tread to the next tread directly above it, the rise will be doubled, or 16".

4. 
   jimstock1 | Nov 30, 2007 04:23am | #4

   tim,

   Check out these prefab alternating tread stairs. 

   http://www.lapeyrestair.com/

1. 
   TimNW | Dec 03, 2007 10:34pm | #8

   Jim, (and others)Thanks for the great info. It's amazing how much information is out there...when one uses the correct search terms!The Lapeyre site shows a range of angles in their stairs; I'm inclined (bad pun) to use a 56 degree angle with fairly normal tread/riser dims. I'll draw it up and post a diagram. I then hope to mock it up with rough lumber to make sure the client can use it.

5. 
   rlrefalo | Nov 30, 2007 06:56am | #5

   If you're considering using one of these I would suggest you find one to try. I find them very awkward. Should avoid IMO.

1. 
   observer | Nov 30, 2007 08:47am | #7

   I put a set in a 42' Grand Banks to allow a 70 year old woman to access the master cabin. She just had to remember to start on the same foot every time.

6. 
   Ragnar17 | Nov 30, 2007 08:38am | #6

   Tim,

   I've built one of those before, and I've heard them called a "Jeffersonian staircase".

   I posted some information about it in a thread a while back. If you search "Jeffersonian" maybe you'll come up with something.

   For what it's worth, the clients had grade-school-age children at the time, and they were able to navigate the stairs just fine (as were the adults).

7. 
   WindowsGuy | Dec 05, 2007 07:44pm | #9

   I agree with mocking one up to try first.  In most cases like lofts, etc. a ladder will be better. 

   I got very close to building one of these stairs a few years ago for a loft until I mocked it up myself and tried it.  It's okay going up, but downright dangerous coming down.

   Code Issue?

   I suspect you'll find that most local codes will not allow an alternating tread stair. These stairs are certainly not for a space designated for living as opposed to storage.  I might use one for a storage loft, but never a sleeping area.