Bearded dragon UVB strip placement in PVC builds

Building your own enclosure is a great move — PVC holds heat beautifully and you can get the layout exactly right from the start. That said, bad lighting is the single most common husbandry mistake with bearded dragons, and it's worth getting this built in correctly rather than retrofitting later. Incorrect UVB positioning or the wrong output causes metabolic bone disease and chronic illness that many owners don't catch until real damage is done. To help you plan this properly: what are the internal dimensions of the build, what UVB strip are you planning to use (brand and wattage), and how old is the dragon?

Good instinct going with Arcadia T5 HO — the 12% is exactly right for an 8-month-old dragon that's past the juvenile stage but still growing. For a 120cm wide enclosure, you want the 1200mm T5 tube, which covers the full length. Now, placement inside the build is where most people get it wrong. The tube needs to sit inside the enclosure, not on top of glass or mesh — both block a significant percentage of UVB before it reaches the dragon. Mount it flush against the ceiling at the back half of the enclosure, directly above where the basking zone will be. You want the dragon's back to be 25–35cm from the tube surface when it's basking — that's your sweet spot for the 12% output. Any closer and you risk UVB overexposure; much further and the Ferguson zone drops off. Can you tell me what you're planning for the basking setup — separate halogen or a combined MVB?

Separate halogen and UVB is the right approach — it gives you independent control over both and halogens produce a far better quality basking heat than combined bulbs. At 25cm below the ceiling, your dragon's back will be right in the ideal range for the Arcadia 12% — that positioning will work well. One thing to build in while you still can: run the UVB fixture on its own timer, 12–13 hours in summer and around 10–11 in winter to mimic natural photoperiod. Arcadia reflectors make a real difference too — the tube on its own throws UVB in all directions, the reflector directs it downward and meaningfully extends the usable gradient across the enclosure. The specific product I'd go with is the Arcadia T5 HO Dragon Lamp 12% 1200mm with the Arcadia Slimline Controller and Reflector unit — it's all one kit, straightforward to mount inside the build, and gives you proper output data you can trust. What material are you using for the ceiling — will you be fixing directly into PVC or building a light shelf?

That works perfectly — the Arcadia Slimline kit comes with solid mounting hardware that fixes cleanly into PVC. One last thing worth building in now: replace the tube every 12 months regardless of whether it still glows. UVB output degrades well before visible light does, and at 12 months the tube may be putting out as little as 50% of its original UVB — enough to look fine but not enough to keep your dragon healthy. Mark the install date inside the enclosure so you don't lose track. You've got a solid setup here — this dragon is going to have proper lighting from day one, which makes a huge difference long term.

Good stuff. One small thing before you do — double-check the kit lists the 1200mm / 48 inch tube size when you order, as Arcadia sell the same controller unit with multiple tube lengths and the 1200mm sometimes needs selecting separately. Enjoy the build — a well-lit PVC enclosure at that size will set your dragon up properly for years.