My company is opening a new office in an existing office building. While inspecting the office prior to move-in, I noticed that the attics between all suites in the building are open to each other. Someone from another suite could easily gain access to ours by just pushing open the folding attic stairs.

What is the best way to secure the folding attic stairs? I considered using a padlock, but the ceiling is too high to open a padlock using a ladder. Do they make a lock attached to the pull cord?

  • 1
    All I can think about is National Lampoon's Christmas Vacation.
    – Peter
    Dec 13 '10 at 20:44

If you are not opposed to replacing the ladder, they do make attic ladders with integrated locks (i.e. Fakro Insulated Wood Attic Stair Ladder. It looks like you need a special "handle" mounted on a 3 foot pole to lock and unlock the latch. I'm not sure if these locks can be accessed from the top, but it is at least worth looking at.

If you prefer to leave the door in place, you could attempt to retrofit a remote control deadbolt to the door. Depending on the style of door and the way it is installed, this may or may not be possible.

  • If the frame can't handle a deadbolt, you could perhaps just mount it into some 2x4 to simulate the door and frame it would normally mount into, and then mount those to the joists...? Dec 11 '10 at 10:46
  • i actually found a remote control lock that has a bolt like on a door handle. clicking the remote retracts the bolt for 5 seconds, then it springs back. so closing the door automatically locks it.
    – longneck
    Dec 17 '10 at 15:12

You could fit a slide bolt on the frame of the door, and then attach a secondary pull string (or keep a separate pole and hook) to operate the bolt.

slide bolt slide bolt 2

  • 1
    You might have to WD-40 the heck out of the thing. If any weight rests on the bolt, you'll have to overcome friction. Pulling at an angle on the string will cause even more force to be required. Steel on steel coefficient of static friction is 0.7. So for a 15° angle from the vertical on your cord, using T=µW/sin(Θ) yields a minimum tension of triple the weight on the bolt. Not to mention the downward force on the string will cause the bolt to bind, introducing more friction. It may well become self-locking this way.
    – Doresoom
    Dec 10 '10 at 18:27
  • It depends on several factors. There will likely be no load from the door (due to the internal spring mechanism). The friction could also be reduced by choosing a chrome plated lock as opposed to the raw steel. As for the pull string, you could substitute a pole and hook, which you would store until you need to open the door. Dec 10 '10 at 18:41
  • I'm getting a minimum angle of 64.5° from the vertical for it not to be self-locking (Using µ=0.7). That's going to be a long pull cord. If you can reduce µ to 0.2, then you're good with 30°, which is viable.
    – Doresoom
    Dec 10 '10 at 18:53
  • With the addition of a pole and hook, this is a practical option. I'll give you the +1 for rolling that into your answer. (Sorry I got a little carried away with the physics - I happen to like this sort of problem.)
    – Doresoom
    Dec 10 '10 at 18:55
  • 1
    @Doresoom: Damn engineers always complicating things.
    – Tester101
    Dec 11 '10 at 4:08

I would wonder if there are any fire code issues with locking it, beyond the issues of locking and releasing it from some distance away. Though if there isn't an "Exit" sign on it, I don't imagine it's required by fire code.

Do you have or intend to install an alarm? It would be a simple matter to make the alarm include a sensor for the ladder being opened. Sure, someone could still get in, with the siren blaring and hopefully the police on the way. It'd have to be someone with access to one of the other offices, so hopefully it wouldn't take Sherlock Holmes to figure it out... :-)

  • good suggestion. we are going to alarm the attic door.
    – longneck
    Dec 17 '10 at 15:10

I doubt there's actually a manufacturer of such a mechanism. A device designed to intentionally lock someone in an attic doesn't have much of a market. However, you can probably build something that will work fairly cheaply.

First off, you shouldn't need a lock. If your goal is to stop someone from entering your office through the attic, you just need a mechanism that is only accessible from below. (Although, an automatic locking mechanism that snapped into place when the attic door closed would be a recipe for shenannigans in my office. Lots of people might 'accidentally' get locked in the attic.)

Something attached to the pull cord that pivots out of the way when pulled would work best. Possibly a spring loaded double strap hinge that overhangs the door with a bracket to hold it in place? This setup might work if you can get the geometry and spring tension right (I call patent rights if it actually works!) :)

alt text

(No making fun of my MS Paint skills)


I'm not sure how well they'd take to being mounted in that orientation, but there's various latches as used for kitchen cabinets that might fit the bill.

Look for either 'Hoosier cabinet latch' or 'icebox latch', either might suit your need with minor modifications (a spring added or a hole drilled), but they're more a deterant -- someone who wants to put enough weight onto the attic stairs could likely open it, but it'd be pretty obvious how they managed to enter your office.

update : the specific style I was thinking of is in the McMaster-Carr catalog as a 'Door Face-Mount Latch', and then you could drill the handle to provide a rope pull. (assuming that the weight of the handle itself isn't enough to open the latch when mounted overhead)

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