How to set up a reptile enclosure, in order

Why order matters more than equipment

A setup assembled in the wrong order forces you to undo things. Substrate before sealant cure means pulling the substrate out. Lamp before hardscape means re-measuring the distance after the basking rock changes the height. Animal before the temperature log means you are tuning a live enclosure, which is the one situation where a mistake has a cost beyond money.

So the sequence below is the one we use, and the waits in it are not padding. Every one of them exists because something has to finish before the next step can be measured.

Step 1 - Place and level the enclosure

Before anything goes in it, decide where it lives. Out of direct sunlight, because a glass enclosure in a sunbeam becomes an oven that no thermostat can correct. Off the floor, where the room is coldest and draughtiest. Away from a heating or air-conditioning vent, which is a temperature source your thermostat cannot see. And on something that will hold the weight: a 48 x 24 x 24 in enclosure with 4 in of substrate and a water dish is heavy, which is why enclosure stands are worth getting right.

Level it. An unlevel enclosure pools water at one end, which is where scale rot and substrate mold start.

Step 2 - Sealing, backgrounds and the full cure

If you are sealing a wooden interior, siliconing seams or foaming in a background, this is the step with the longest wait and the one people shorten. Use the published full cure time, not the dry-to-touch time, and ventilate the room while it cures. Our non-toxic sealants page lists the figures product by product, and reptile-safe paint covers the same question for coatings.

Step 3 - Substrate, at the published depth

Depth is a figure, not a preference. For a burrowing species that is a 4-6 in packed layer per the substrate guidance, which is a surprisingly large quantity - budget for it. Pack it rather than fluffing it; a loose layer will not hold a burrow and a burrow that collapses is the thing you were buying depth for.

Match the material to the species moisture target: 30-40% ambient, with a humid hide at 70-80% for a leopard gecko, 60-80%, allowed to dry back to 40-50% between mistings for a crested gecko, and 30-60% ambient average for a bearded dragon. The substrate roundup and substrate depth have the detail.

Step 4 - Heat, on a thermostat, before anything else electrical

Install the heat source and its controller together. There is no stage of this process where an uncontrolled heat source is acceptable, including the testing stage - an enclosure running empty at 140 F is a fire question, not a husbandry one. Match the controller type to the heat source: dimming or proportional for a light-emitting lamp, on/off only for a lightless emitter. How thermostats work explains why, and heat lamp fire safety covers the failure modes.

Place the probe where the figure is stated. A basking surface figure is measured at the surface; a warm hide figure is measured inside the hide. A probe dangling in mid-air is measuring something nobody published a number for.

Step 5 - UVB, mounted to a published distance

Build the hardscape first, then mount the lamp, because the distance is measured from where the animal will actually sit. A bearded dragon needs UVI 4.0-4.5 at the basking surface at the basking surface, which for a 12% T5 lamp means about 11 in through mesh. A crested gecko needs UVI 1.0-2.0 at the basking branch at the basking branch. Those are different numbers for different lamps - UVB distance and Ferguson zones has them all.

Put both lamps on a timer at the published photoperiod. Write the UVB install date on the tube in marker, because the replacement interval is 12 months and you will not remember.

Step 6 - Hides, cover and water

Three hides minimum - warm, cool, humid - and cover breaking every open run. Stand at the front and look through the enclosure at floor level; if you can see straight through it, it is not furnished. Water dish at the cool end, where it will not evaporate into the basking zone and lift ambient humidity above the species range.

Step 7 - Run it empty for three days, and log it

This is the step that separates a setup that works from one you spend a month adjusting. With everything installed and on its timer, take readings twice a day for three days: basking surface temperature, cool end temperature, ambient humidity, and the overnight low. You are looking for the figures to hold across a full day-night cycle without intervention.

If the cool end never gets cool, the enclosure is too short or the lamp is too strong. If humidity drifts outside the range, fix it structurally now - how to increase humidity and enclosure ventilation both cover the levers. If the overnight low undershoots, you need ambient night heat, not a brighter day lamp. All three of those are easier to fix in an empty box.

Once the readings hold for three days, the enclosure is ready. Species-specific checklists pick up from here: bearded dragon, leopard gecko, ball python and crested gecko.

Four maintenance pages pick up where this build order stops. What temperature should a reptile enclosure be puts every species figure in one table, how to keep a reptile enclosure warm covers cold rooms, winter and power cuts, how to clean a reptile enclosure sets the three cleaning routines, and if the enclosure is a build rather than a purchase, how to seal a reptile enclosure is the layer order and the cure clock that has to finish first.