Tuesday was a really big day – excavators at 9:00, building inspector at 11:30, bunker installation at 3:30, backfill at 5:00. Can’t believe something finally went to plan!
We’ve been sweating on the bunker availability and the weather. Installation would be easy if the bunker was installed before the house – the truck could just back over the prepared pad, and consolidated ground for the track to it and lower it in, otherwise it would need to drive over unconsolidated ground in a big arc and potentially get bogged. We got notified last week that it would be available on Tuesday, 6 months after we ordered it. Weather forecast was for rain over the weekend, but Monday and Tuesday were supposed to be fine. So finger’s crossed, we booked it in.
We didn’t want to leave the hole open and fenced, due to the risk of the kangaroos investigating and knocking or jumping over a fence and falling in, or it raining and filling up with water, so we organised for the hole to be dug in the morning – 2.4m x 3m x 1.4m deep, with 100mm backfill fine gravel for levelling and ensure no stones pressing on the concrete base of the bunker. We got our two days of fine weather, and the digging went well. Our consolidated clay and gravel soil held its shape well.
Building inspector turned up half an hour after it was finished, and gave it the thumbs up.
The bunker turned up at 3:30, and was in the hole by 4:30. Simple.
Our little Kubota tractor bucket was perfect for moving the soil back in to fill in the gaps around the 2m x 2.6m bunker (200mm clearance all round for the hole). A bit of shovel work, and it was firmly in the ground. We still need to mound 300 – 600 mm soil around and on top to provide additional insulation, but the rain has been bucketing down since Wednesday, so that will have to wait for a bit.
It’s the first time we’ve seen the bunker – we bought it online without going to look -Melbourne was in lockdown so we couldn’t go to see it. It was a pleasant surprise – with arthritic knees, I wasn’t totally convinced I could get in (easily). I figured with bushfire adrenaline I’d make it in, and that Mark could always give me a hand. But actually it was no problem at all. Grab rail on the door, and marine ladder rails made access easy. The fire door is really stiff to open – that might be my only challenge. Will need to practice, build muscles or try some more lubrication, or all of the above. We thought it would be really tight and claustrophobic, but it feels surprisingly spacious. I hope we never have to use it, but I wouldn’t go crazy locked in there for an hour with 6 people. We could all stretch out.
The battery operated lights with well located mounting points, clock (max one hour for 6 people once it’s closed up), viewport, temperature gauge (measuring outside temperature) were all nice touches we’d forgotten about.
So what have we learned?
Our bunker does have a slight tilt to the back, maybe about 5 cm across the bunker length. I think its a little heavier at the back. We should have compacted the backfill more, and made sure we had the same amount at the back and front, so that it wouldn’t compress more on the back than the front. Torrential rain on Wednesday likely didn’t help, because with the very slight slope on the site, more water pooled towards the back. It isn’t visible from outside even without the mounding, and from inside you have a suspicion of it, but its not until you put something round on the floor that its confirmed. And then you get out the spirit level…. So not a biggy, but it would be nice to be dead level.
Wildfire delivered as promised, with only a minor niggle – their billing and progress updates are pretty rubbish – they took ages to send us a receipt to confirm that we’d paid the deposit and they wouldn’t deliver the bunker until we paid in full. We had to chase them to find out what was going on and when our bunker would be available. But Anthony was always very friendly and helpful, as was Tim the installer.
They say there’s now a 12 month wait for a new bunker. Tim said that installation normally wasn’t this easy, because access is usually really hard. We’re so pleased that we’d planned it out, got it in before the slab was down and the weather was kind for once.