You know, I think that is something great to keep in mind while trying to make virtual builds as they are very modular. It's not so good when you are like me and possibly plan to make a real prop. If I do eventually happen into some money, how would I make sure I don't end up with an eye sore after a rainy day? How would I manage my funds? And seeing as you have made a custom build like I plan to, do you have any advice?
Probably not the appropriate place to ask, but it was the spot where I felt comfortable. (Sorry for the rush of questions, it's best to just get all of them out of the way instead of a series.)
Geez. The build diary is probably the best place for advice. Or countless threads where other people have started a build and asked for advice. But I'll take a stab at it:
1) Most of the things you think are good ideas will turn out to be terrible ideas. For example, my build was justified as a place to put stuff from my garage while I was putting a concrete floor in the garage. The garage also leaked, so I was going to make my TARDIS completely waterproof--so no actual windows (the windows were painted grey/silver and then the fake window's pane and trim was stuck on the front). It turns out to be impossible (at least for me) to do a waterproof outdoor build--and even if you do, water gets in from condensation. So over the years I've added ventilation. At first my TARDIS was on dirt. I think it had plastic under the whole thing, but that was it--dirt, plastic sheeting, TARDIS. Eventually I levered it up off the ground to put bricks under the cornerposts, but when I moved I was happy to have an actual concrete pad in my driveway to put it on. Turns out that all the water that runs off a TARDIS pools around its base and the bottom rotted like crazy on that concrete. So the next time I moved I put it back on dirt, with a 14" square paver under each corner and a plastic barrier. But I was still trying to use it for storage so I had a stack of tires/wheels loaded in it. Well because the door opens in, the tires have to be stacked in the corner opposite the door hinge. This, combined with soil of varying density, caused the TARDIS to warp so the top of the front facade is twisted about 1" from the bottom.
2) On a related note, ventilation is important for outdoor TARDISes. Originally I had a vent designed into the signal lamp. (You'd think being on the very top, that would be an entry point for rain, but you'd be wrong. Because the lamp is relatively small and the roof slopes away from it. Plus it is designed to shed water. So very little water can get in that way. You get much more water coming up from the ground around the box. I also wound up leaving a gap at the bottom of the POLICE BOX signs at the back when I remodeled. And the floor is ventilated with most of the base ever so slightly up off the ground.
3) Related to that, how you build your TARDIS should factor in its purpose. Will it be indoors? Do you want to be able to pack it up and take it places? Will it be outdoors? What is the weather like where it will be? In the design phase I considered fairly thick plywood because I was concerned someone would steal it, but TARDISes are so much bigger than you realize that every aspect of moving one is hard so I went with the thinnest practical plywood.
4) My initial build wasn't very accurate. The goal was to keep the build simple and costs down by simplifying the plan (maybe *that* is how the 2005 prop wound up so different from the plans!). But after a few years I was unhappy with the inaccuracies and figured out a way to retrofit a veneer onto the box to make it more accurate. At this point I'll touch on water again. As part of my simplification I didn't have any bevels on the wood trim. But it turned out the reason for bevels on outdoor wood isn't because it looks neat, it keeps water from pooling. Even if I caulked the trim, water would find its way behind the wood. First it got in where the screws connected the trim to the plywood and eventually it rotted a trim-shaped checkerboard in the interior plywood. During the retrofit I used premixed thinset plaster you can buy for tiling to add bevels to the trim. I've also used it to patch rotten spots--and just to add texturing. I've increasingly started patching with concrete and that's been fairly durable but it has started to crack and separate as the wood under it flexes and shifts. I've also added leftover panels of Hardibacker cement board on the inside as the orignal plywood has rotted. Currently I'm working toward fiberglassing the exterior. The roof to the bottoms of the POLICE BOX signs is totally 'glassed and next, when I get time and money, I'll start working up from the bottom, where most of my worst rot problems are.
5) At first I put a lot of effort into artificial weathering. But as age has added...character...I've learned the most effective weathering is just not getting an exact match for the blue you're using--and being intentionally uneven about applying it. But even this has backfired. The last time I painted, the new paint had a lot of red in it, making it almost purple, while the old paint had more yellow, making the blue greener, and it was a jarring effect so I had to paint the whole thing evenly. You can still see where I didn't paint the window trim and the color difference is pretty noticable. Or where I found a blue plate while walking my dog that was the perfect size to replace the plastic top of my signal lamp that had been cut from the bottom of a dollar store bucket and had been rotted away by sunlight. It was a perfect color to match the old paint. As it is, there's a purpleish lamp with a greenish band up near the top. Oh well.
6) And while you asked for build advice, I'll add the obligatory maintence tip I don't follow as well as I should: Inspect periodically for leaks, wear, and damage and repair as well as you can. Paint periodically to help protect the wood.
