Platforms, Stairs and Wagons

Platforms, stairways and ramps are necessary whenever a change in floor levels is required, which happens very often.

Platforms

Platforms are the most common pieces for adjusting elevations or creating a show deck.

The tops (or skins) of platforms are usually made of plywood. 3/4" is the usual thickness, but 5/8" is sometimes preferred for a small weight savings. A theatre should stick to one or the other, though, so that platforms with the same length legs will be the same height. Because plywood comes in 4x8 ft sheets, platforms are usually made in 4x8 units, or in some even number thereof.

Platforms are usually made with frames of wood or tubular metal. 2x4s are probably the most commonly used material for framing. It is readily available, cheap and can be assembled with a variety of fasteners. The finished platform is 4 1/4" thick.

The strongest platforms use tubular steel or aluminum for the frame. They require a qualified welder to build properly, but are most durable, especially for a road tour where the set needs to be both transported and assembled/struck often. They are more difficult to leg because they are metal.

Most theatres will have a bunch of stock (or reusable) platforms on hand to use to create various size decks. The most common stock sizes are 4'x8' and 4'x4'.

Legging platforms

You can vary the heights of platforms easily by legging. There are three common methods for wooden platforms.

Simple bolted leg: A leg, usually of 2x4, is cut to the desired height minus the thickness of the platform lid. It is then placed inside the platform corner and two bolt holes are drilled through with holes placed at a diagonal to each other. The best bolt for this is the 3/8" Carriage bolt, usually about 1/2" longer than the platform and leg thickness combined.

This system is simple and direct, and reasonably strong. However, the weight is carried only on the bolts and bolt holes, and if there are not enough legs or too much weight, the platform frame may split or the bolts might shift, causing the weight to be borne against the lid. This can cause the lid to pop.

Compression or step legs: For these, legs of the same thickness as the stiles and rails are cut to the height desired minus the overall thickness of the platform lid and sides. Then a bolt plate of 1x stock is laminated to the leg with screws and/or glue. This plate extends past the leg to the thickness of the platform frame minus about 1/4" or so. The extension plate can be the full length of the leg for a little extra strength, or can be applied to the top foot and a half or so of a long leg to save material. Compression legs are stronger than simple legs; the weight of platform bears directly onto leg in compression, rather than by the bolt holes, so it can bear more weight. The sides won't split and the lid never carries the weight. Since the bolts are not load bearing, they can be smaller, 1/4" rather than 3/8". Often flathead bolts are used rather than carriage bolts, so even the slight bump of a carriage bolt head is avoided.

Trestles are another useful system, especially where large raise decks will be used. Also called Knee walls and Gate Supports, these are built like the stud walls of a house (and sort of like a Hollywood flat laid on its side), with top and bottom plates and vertical "stud" legs on 2' to 4' centers. The stud frame is the desired height of the deck minus the thickness of the platforms. The trestles are set in place and platforms are set on top of and secured to the top plates of the trestles with long screws or bolts. Trestles are placed on two to four foot centers, and may run under several platform units. Essentially it is a decking system rather than individually legged platforms fastened together.

Trestles may be built as stock and stored for future use. They are a little slower to built, and bulky to store, but allow extremely fast assembly of large decks once the trestles are built. They are also very commonly used for metal framed platforms.

Stairs

Many sets have multiple levels, which require stairs in order to get to them.

Stairs have several parts. The tread is the part that you walk on. The carriages are the sides of the staircase that support the treads. Risers are the boards that cover the front of each tread. Stringers are similar to carriages, but support the center of the treads.

Stairs are described according to their kind of support: independent and dependent.

Independent stairs are stairs that hold themselves up. They are either plywood stairs where the sides go all the way to the ground, or they are legged like a platform with standard legs. The stairways is also closed underneath. Independent stairs put no stress on the platform they are beside, but they are bulky to move and store.

Dependent stairs need the unit they are against to hold them up. This can be done by bolting the stairs to the platform or platform legs, or using a support board that is attached to the adjacent platform, to which the stairs are hooked. Dependent stairs are not self-supporting but take less room to store.

Rise and Run

Stairs should be laid out using a consistent rise to run ratio (height of the step and depth of the tread) to prevent tripping. There are several "rules of thumb" which will help determine a proper ratio to make a stairs comfortable to climb. An easy one, and the most common, is the Rule of 18:

When measured in inches:

Tread + Rise = approximately 18"

For example - for an 8" riser you would use a 10" tread, because 8"+ 10" = 18".

Ramps

Are another common way of getting from the stage floor to the top of a platform. They require more space than a staircase, but can provide a smoother transition for the action of the play from one level to another.

Ramps are measured according to the ratio of their slope or incline. The general rule is that ramps do not want to be steeper than a 1:6 ratio, which means that the ramp will rise 1" for every 6" of length.

Ramps are typically built with triangular trestles that are then lidded with 3/4" or 5/8" plywood.

Wagons

Are simply platforms that are on casters (look like small wheels) rather than legs. If a wagon is particularly low to the ground, it is called a palette.

Casters come in two types: fixed (or "dumb") and swivel (or "smart"). Fixed casters are used when wagons only need to track forward and backwards, while swivel casters are used to allow any direction of movement. Casters are bolted to a support called a caster plate which is then attached to the lid. General rule is that you want at least a pair of casters every 4'.

On some bigger shows wagons might be tracked, meaning they have a metal blade-like piece called a knife that connects the platform to a groove in the floor. By doing this, the wagon will stay within that track and can only travel along a predetermined path. This can be either mechanically driven through a department called Automations, or can be people powered by pushing.