Hi there, I’ve read that article and in there somewhere it does mention high water tables. It’s a little more important than that. A high water table during building works ( summer ) will usually mean a much higher water table during the wetter parts of the year and as we all know, that’s most of the time in the U.K. So my advise is, if you’ve got any seeping water in your footings in the summer, then build your garage and forget about a pit. If there’s no seeping water then you’re in with a very high certainty that it’ll be ok. With your roof, don’t go for a standard trussed roof as that will limit your internal height and how far you can jack your bus because of the integral ceiling joists on the trusses. Maybe have your roof designed with a standard truss front and back against the gables for stability and integrity then have the rest of the trusses made with raised ceiling joists like in a house built with a loft conversion from new. A little more expense but minimal in the overall cost..Get your sparks when carcassing to provide your own fuse box in the garage so you can have separate circuits, I.E. one for lights, one for all power points, one separate for the pit so you can separate it if there are ever any water issues and a nice big fat one for any welding done. I’d also look at a small ish solar panel and just use it to charge your batteries in the van and your cordless power tools, it’ll save you a few bob and make you pleased with yourself too, you can always charge with 240 if you’re in a real hurry. Im pretty sure your bus is a bit lowered so I’d make sure there’s a couple of inches of clearance at stock height or more for the bus entry. As far as doors, there’s a million and ten doors ideas and most can be custom made. If you’re having a roller shutter from new, you’ll need twelve to eighteen inches inside for the roll of the door when it’s rolled up which may play havoc with your new fancy roof design because it’s the massive tent of wooden roof structure that holds all the walls together and not the other way around which is why the gables and walls are all strapped with long galvanised straps to the roof wall plates. Don’t even entertain a hipped garage roof if you’ve any intention of doing any more than parking a car and a lawn mower in there, and definitely not if you’re looking for a roller shutter door. With up and over doors, cantilever doors, sectional doors, look out for frame heights that will differ from opened door heights that will differ from opening door heights as they’re operating and also doors opened but with additional bracing for double doors etc.
Id love a pit but my water table has other ideas. Yes that GRP unit will stay waterproof for a long time but the joint between that and the concrete will have water sqidging past it in the first wet season unfortunately.
Ozziedog,,,,,,,,,,,there’s a few bits to chew on