When do you need to build a podium?
A podium is defined as a platform that is raised above existing surroundings so that it gives prominence to the person or persons on it. While "podia" also refer to the objects behind which speakers stand to deliver lectures, the question of how to build a wooden podium here should only come from people who want to build a temporary stage that will create a necessary platform for speakers or other events that are one-off affairs. Maybe it is an election rally, an event to honor someone, or just a gathering of likeminded people. Such podiums are also needed for large musical shows and media events, but their construction would quite often involve more sturdy materials like steel or aluminum and would seem more semi-permanent in nature.
Image Source: Wikimedia: Covered podium
Deciding on the podium
You would need to define the size of the podium by finding out the maximum number of people that will be on it at any given time, the actions they will be performing, and also the size of the audience expected. If seating arrangements are being made on the podium, you would need to have sufficient room for the chairs and spaces to move around them. Space for tables or other equipment like sound or lighting would also have to be made.
Creating the podium structure
Mark out the podium area on the ground at the location decided for the podium. You would need to create a basic framework to support the stage and take all the weight of the people, furniture and equipment on it. You cannot go wrong if you use 4 X 4s of timber as posts to act as columns to support the structure. Normally podiums would not be more than 3 or 4 feet in height and you would probably need the 4x4s to be a length of about six to seven feet if they are to be embedded in the ground. Mark out a grid of 3 feet by 3 feet within the podium area and dig holes 2 to 3 feet deep which can take the 4×4 posts. Put the posts into the ground and fill them up properly till the posts hold firm. Concreting these bases can make the structure safer, though it is not strictly necessary. If the ground is firm enough, just creating the framework should be good enough and you need not embed the posts in the ground. The posts can then be as long as the proposed height. Connect all the posts in the shorter direction with planks of 6 inch by 1 inch so that the top of the planks and posts are at the same level at the top. Use similar planks in the longer to connect the posts and plank structure with planks laid flat. This will form the basic structure and now for the flooring of the podium.
Flooring of the podium can be done with plywood or other material. Just see that it is strong enough to take the anticipated traffic. Using readymade steel plates is quite common, as they are easy to rent out and can be easily laid down and removed. They would however require some sort of matting or carpet to deaden the noise that can be created by people walking over them. Some podiums may need to be given some protection from the sun, if events are being held in the daytime, then a separate structure to hold up the sun shade may be necessary.
Other points to be considered
If the height of the podium is increased, you may need to brace the vertical posts at intervals so that the structure has more strength and can take any horizontal forces. This can also help to take care of wind forces which can affect podiums because of the openness of the structure. Make sure that your podium has provision for fire extinguishers as the wooden nature of the podium makes it a fire hazard. Position sufficient sand buckets all around the podium before the start of the event. How to build a podium would have you making provision for electrical connection for the audio and other equipment and lighting where necessary. You need to make sure that all such wiring is done in suitable shielded cabling and with no open wires.
Provision has to be made for sufficient means of entry to the podium top in the form of temporary stairs and there must be a sufficient number of these both in the front and at the sides and back. Ensure that these have handrails which can help the elderly. During construction it must be kept in mind that the structure would have to be dismantled and connections made should be such that can be easily removed while at the same time give the necessary strength during the use of the podium.