putting concrete down for scope

[sejanus (Gavin)]

well, I'm a total dummy at anything unless it's a keyboard or a camera.

So I want to put my lightbridge on a smooth surface. my backyard has quite a bit of a slope on it, so the lightbridge is a bit unbalanced there and will often move by itself. on my driveway though which is flat it is fine.

I suspect it'll be fairly easy but thought I'd check. I plan to basically make a little box on the ground with some bits of wood. Pour the concrete in the 'box' and then flatten it out and adjust with a big spirit level as much as i can and then let her dry

am i missing anything? I'll be digging down a bit first i.e. so the concrete won't be above grass level.

cheers

[Dennis]

For the only concreting job that I have ever done, a crazy paving patio back in the UK, I filled the base with rubble (100mm depth) and then I put a layer of builder’s sand (50mm depth) on top before finally pouring the concrete. I also put a 1 in 40 slope on it, so the rain didn’t form a pool on the patio.

Cheers

Dennis

[Inmykombi (Geoff)]

Sounds like you have it under control, however I might add that you should dig down quite a bit ( maybe 125 - 150 mm ) to make a nice stable SLAB of concrete.
If its too thin it will crack and become uneven.
Maybe you could also find some steel to re-inforce the slab as well. That would stop it from cracking. Say and old washing up rack that you could cut up a bit.

Also, if the ground slopes around the concrete platform, maybe some gravel ( blue metal ) would do well on the high side to allow any build up of water to drain around the slab and not sit near it an not seep under it.

Hope this helps.

[Glenhuon (Bill)]

You have the basics right Sejanus, but build the box to the required size and place a straight piece of wood across it each way diagonally to check the level. Make sure the box can't move when you pour the concrete by putting pegs around the outside with the tops below the level of the box . When its poured use the long piece of wood to scrape the excess concrete off down level with the top of the wooden box. Should give you a pretty level base for the scope.

Cheers
Bill

[Ric]

A quick thought Sejanus, if you smooth off the concrete too much it can become slippery with dew. An easy way around this is to lightly drag an old broom across the slab which will slightly rough the surface and give you shoes that extra bit of grip.

Cheers

[sejanus (Gavin)]

thanks heaps for all the info guys, I'll attack it this weekend

cheers

[ballaratdragons (Ken)]

Another thought:

You can buy quite large concrete paving squares! Saves you doing the concreting.

Just dig down and make a level surface, then lay the big paver on a layer of sand. It should settle in a day or two

If you can't find a paver big enough, stonemasons and Headstone cutters sometimes sell seconds of large cut stone pretty cheap.

[[1ponders] (Paul)]

Which everway you go, concrete pad or pavers, think about getting hold of some old outdoor carpet to stick to the top of it. It may not be much but it may be just enough to save that "Oh No!" dropped eyepiece.