The first requirement of building a reptile terrarium is understanding the requirements of your reptile. Different species of reptiles have different requirements, and not meeting the specific requires could result in illness or death.
Here are some things to consider before building a terrarium:
1. The species of reptiles
2. The number of reptiles kept in the cage
3. Their potential growth size
4. Their heating/watering requirements
5. Their lighting requirements
6. Their humidity requirements
7. Safety needed against external factors [other pets, children, etc.]
8. Placement of terrarium in house [corner cage, etc]
After you have determined the requirements your terrarium you are ready to plan to start planning a simple blueprint. To start off with, write in the upper corner of your paper the dimensions your cage will need to be: length, height, and depth.
Next, determine the materials you will make the terrarium out of. This is best determined by the requirements of your reptile and the environment your cage will be placed. If your reptile requires high temperatures and the terrarium will be placed in a cool environment, wood is the best material to retain heat, followed by plastic; glass is the worst material to be used, as it allows heat to escape effortlessly. If the reptiles are arboreal and an placed in a warm environment, your habitat can be as simple as a wire mesh cage.
After you have determined the material you will make your cage out of, you can start planning on the design. First, consider heat and lighting. Will your reptile receive both its light and heat from a lamp, or will it also have a heating pad/flexwatt tape?
Some prefer to make the entire top of the cage out of a wire screen and simply place the lamp onto the screen. This is fine if normal humidity levels are acceptable. However, higher humidity levels will require an enclosed top. You can then cut an opening the size of your lamp and over lay that with wire. This way will allow heat to escape, however. Most prefer to make a small “basket” out of wire and allow the basking lamp to rest just below the top of the habitat. Just be sure that the lamp is out of reach of the reptiles, as the wire will get hot.
Ventilation will also need to be considered. If you have an open mesh cage, then ventilation is not an issue. However, if the top of your cage is solid, you will need a minimum of two ventilation sources, one on the top and one on a side of the cage. Many people install computer fans into the top of the cage by cutting a fitted hole and attaching a battery pack to it (both available at RadioShack for about 5USD). Be sure that wire is placed over the fan to prevent your reptile from becoming injured on it. If you do not wish to use a fan, you can instead drill holes in the top and sides of the habitat.
If an under-tank heating pad is going to be used, the bottom must have a section made out of the appropriate material, usually glass. Be sure to read the cage requirements on the UTH you purchase. These heating pads cannot be attached to wood or plastic.
The last issue is visibility. If you are making the terrarium out of any material that is transparent this is not an issue. However, if you are making it out of wood, you may wish to add a window through which you can observe your reptile. These can be as simple as wire mesh, as durable as Plexiglas, or as beautiful as glass. Keep in mind that Plexiglas is expensive and scratches easily and that glass is heavy and does not retain heat. Wire mesh will also allow heat to escape, but may not be an issue depending on your reptile.
If you prefer to keep the price down, a very cheap option is to buy a Rubbermaid container, cut a square of it out, and glue/staple it to an opening cut into the front of the habitat.
After you have determined these factors and cut the appropriate dimensions, it is time to put them together. Since your materials are ready, this step will be simple and fairly fast. You can use glue, nails, screws, or wire, depending on what you cage is made out of.
Start by setting the bottom board on a flat surface. Attach the two side of the cage, then attach the top. This is will give you an open square. Now carefully lay the cage flat and attach the back. Set the cage back of straight. The front of the cage depends on the type of cage you are making; be creative. Attaching the front will be the same as the rest of the cage.
Now that you have a front, its time to attach the top. You can do this a couple different ways, depending on the cage/ goals. If you are making a wooden cage, the lid is can be safely be made with hinges on the back and a lock or two on the front. You can also purchase a weather strip and create a press-down lid. You can do this by attaching weather strip to the top of your cage, gluing lips to the edges of you lid, and then adding some clasps to the sides of the lid to keep it on.
Now that you have a fully functional cage, you may wish to seal it, depending on what it is made of. With wood, make you sure that you only use a natural sealer, and that it is safe for your reptile. I also recommend purchasing silicone and sealing the inside edges of your terrarium, especially if the sides do not meet flush.
The last step is aesthetics. If you are happy will how you terrarium looks now, then your work is done. However, if you wish to give it a tad fancy look, then break out the sander. You can sand the outside until it is smooth, you can round the edges, or you can give it designs. Also, you can purchase a wood burner and burn some nice designs into it. After you do this, seal it with a couple coats of polyurethane. Be sure that the cage is completely dry before you place your reptile, or else the fumes will likely kill it.
That’s it! Be sure that you take into consideration: ventilation, weight, ease of use, and lighting before building. Write down dimensions before you start and have a rough sketch in mind.