OT - Cellar/Mud Room Trap Door Design

[Erik Oerter]

Hi All,

Thought I would get y'alls opinion about how to go about creating a door/floor for an opening in the floor for a set of stairs in my mudroom. These are stairs that appear to be old cellar stairs that were once outside the house and then somebody built an addition (mudroom) around them. The existing stairs and floor are slab concrete.

I'd like to make some sort of door that would work as a floor over the stair opening when closed and support human weight and activity, but would be feasible to open to access the basement (~2 x month), for both me and the wife.

I am looking for sources/ideas for gas assist struts or spring hinges to make opening the floor/door easier (take the weight off).

How about the latch? I was thinking some sort of rotary fold down d-ring type thing so it was flush when in floor mode.

Also, any ideas on how to construct the floor/door to make it rigid enough to use as a floor, light enough to open as a trap door? I am open to ideas incorporating steel and aluminum.

The floor/door will be about 6' x 6'.

Thanks for your ideas,
Erik

[Bill ThompsonNM]

1. Make the door of torsion box construction and it wouldn't have to be real heavy .
2. I think you hit it on the head with gas assist. You can get assorted gas struts (like the kind used to keep a station wagon rear window from whacking you in the head at any auto parts store

[Lee Schierer]

Take a look at hatch covers for boats and how they are made. Lots of boats have floor hatches and the types of latches you are looking for.

[NICK BARBOZA]

I think the torsion box is the way to go. maybe out of 2x6 (to be safe) 2x4 would probably be fine with 3/4" ply on both sides. I also might consider making 2 - 3' x 6' doors. That might lighten the load considerably and allow the gas struts more effective with the amount of weight they will have to handle.

Are the staris 6' wide? or do the "double back" and turn 180*?

Cheers,
NWB

[Matt Benton]

I built a 6' long torsion box made from 2x4's and 3/4" MDF on both sides, and it has almost no deflection with a 600 lb table saw sitting in the middle. Definitely strong enough...

[Jamie Buxton]

A difficulty with buying gas struts at the auto parts store is that they're spec'd in terms of what cars they fit. What you'd really like to know is how much weight they push up, and how long their stroke is. You can buy struts spec'd in those terms from McMaster-Carr.

[Todd Hoppe]

This guy seems to have every possible gas lift support known to man:

http://www.autopartsbylou.com/

[Rick Lucky]

Hello Erik,
I have also been looking at putting a flush "floor door" over an existing cellar stairway to regain the square footage in an entrance way . Have you been able to design this in your house?

Mine would be an approx. 3' x 7' opening without changing the existing stairs. Also, I hopped to find hinges (maybe cabinet like) that will allow the door to sit flush and open without interference.

Another feature is to incorporate part of the hand rail into the door so, when raised, it would line up with the remaining handrail. Also, if the door can be locking into the upright position, it can also act as a safety guard on one side.

I agree that the gas struts would be the way to go and have seen designs that use tonneau cover gas shocks.

I have seen a few interesting hatch designs and here are some links. The third one down uses gas struts and has an explanation in the comments section.

http://www.cellar-creations.com.au/cellar_ladder.htm
http://www.roofaccessladders.com/cellarladders.htm
http://kims-kitchen-remodel.blogspot.com/2009/01/basement-hatch.html
http://www.flickr.com/photos/kimhascats/3189003530/

http://www.spiralcellars.com/us/examples-dining.htm

I still need to find the right hinges and a latch (like the boat hatch idea). If anyone has an example link to these I would appreciate it.

Rick