The first thing to remember when building a bulkhead is that it needs to be strong enough to support your weight. You need to make sure that the bulkhead will not allow any kind of leakage or air leaks into the room where you are going to place it. If there is no way for the bulkhead to stop such leakages then you cannot use it properly. So if you want to build a bulkhead, you have to make sure that it will be able to withstand the pressure of the atmosphere inside your room.
Another thing that you must consider is how much space you will require for your bulkhead. A good rule of thumb would be to divide the total area of your room by two (2) and multiply it by ten (10). For example, if your room is half of an acre, then you need to build a 1/4 inch thick bulkhead.
In order to determine how much space you will require for your bulkhead, you need to calculate the height above grade of the floor and ceiling joists in your room. Then multiply that number by ten (10), which gives you the amount of square feet required for a 1/4 inch thick bulkhead. That means that you will need at least thirty (30) square feet per cubic foot of room size.
Now let’s take a look at some different types of bulkheads.
Bulkhead Types: Bulkhead Type 1: Drop Ceiling Bulkhead Type 2: Water Ceiling Bulkhead Type 3: Steel Frame Bulkhead Type 4: Wood Frame
1. Drop Ceiling Bunkers – These are the most common type of bulkheads used in construction today. Drop-ceiling bulkheads are easy to build, very strong, and can be used as either a water-tight or non-water-tight bulkhead.
How do you build a drop ceiling bulkhead?
The very first thing that you need to do is to construct wooden joists that span from one side of the wall or partition, to the other side. The next step involves building a plywood platform in between the wooden joists (or girder). This plywood platform should be at least eight (8) inches thick and it should also be big enough to span at least six (6) feet across the entire wall or partition. This procedure is very important since it will support the weight of your future sunken living room.
After you have finished building your plywood platform, you should start filling the space in between the platform and wooden joists with Styrofoam insulation. Just make sure that you leave a small gap near the top of the joists, so that you can pour the concrete into it later on.
Now you can start constructing your bulkhead door (or hatch). You can build your bulkhead door out of plywood, it has to be at least two and a half (2 1/2) inches thick and it must have a water-tight seal around its edges. There are many ways on how you can build such a door. However, the most common way is to use “boat building techniques”. Basically, this means gluing layers of wood around a “buck” (a form or mold of the desired shape of your door).
You should also construct a frame for your bulkhead door. The frame must be at least as strong as the door itself. It should also be water-tight, since any leaks in the frame can also cause leaks in the door itself.
The next step would be to place your bulkhead door inside the opening that you have created for it. Before you place the door inside its proper position, you need to first make sure that the door and frame is water-tight. To do this, apply a bead of sealant around all of the door’s edges and around its frame. Be very careful that you apply an even amount of sealant, otherwise it may leak.
After you have applied the bead of sealant, place the bulkhead door inside its opening. Now take a look to see if you have any leaks. If you do have any leaks, then you will have to apply some more sealant to those areas and the re-check it.
The next step would be to fill the gap between the bulkhead door and the surrounding opening with foam insulation. You can then take this foam and compress it around the door using a piece of plywood and a large object, such as a car tire. The purpose of this is to create a water-tight fit around the door.
After you have compressed the foam, apply a bead of sealant around the door’s edge. Make sure that you only apply a small bead, since you do not want the door to have a bulge when it is closed. Also, make sure that you only apply sealant to the INSIDE of the bulkhead door’s frame (the side facing into the room), and not to the outside (the side facing the hallways).
Sources & references used in this article:
- Fiber reinforced pressure bulkhead with integrated frame (S Roth, D Benz, A Reichle, R Teske… – US Patent …, 1991 – Google Patents)
- Internal bulkhead for spring seat reinforcement (DK Bell, DK Platner – US Patent 6,695,351, 2004 – Google Patents)
- Bulkhead for raising strength and rigidity of vehicular frame members (D Watanabe, T Inoue – US Patent 7,192,071, 2007 – Google Patents)
- Box frame bulkhead (AG Schilberg – US Patent 2,747,887, 1956 – Google Patents)