New observatory in existing shed

[marki]

Originally Posted by Astrodude

Hi again all,

Next job is the rebar.

Anyone know if there would be any issues later (ie. rust) if I sunk the ends of the vertical rebar rods in the clay for stability until the concrete is poured?

Use concrete blocks to stabilise the cage in the hole. You should be able to get them from your steel supplier. Avoid all contact between the ground and reo.

Mark

[Ian Robinson]

For the builder types here :

Every bit of concrete on my property is cracked (most of it is over 30 years old - driveways, footpaths, a couple of slabs (not sure what the prior owner used them for) , and my more recent 6x6m garage slab has also developed a fine crack.

I know much of Newcastle and Lake Macquarie is a mine subsidence area , I also have clay under the soil (which is quite dry now and have been for a few years). There have been road collapses in nearby streets (most recent was about 20 years in Coral Cresent when a big hole opened up in the road).

So how do I tell if the cracking is mine subsidence , or simply due to actve clay ?

This will determine if I go for a slab or an off ground platform for my ROR shed .

[renormalised (Carl)]

To determine if it was collapse due to mine subsidence, you'd have to get the guys from the NSW Dept of Mines to come along with the old mine maps. They could tell you where the old shafts and/or drives were and whether you were on top of one. If it was active clay slippage, you'd have to get a geotechnical engineer to drill your yard and see if it was that.