Soil Test - Good news/bad news?

Hi All

We received our soil test back on land which is sloping. The good news is that it is S Class

The bad news is that appears to be all on weathered rock and we need to some major site works due to the slope.

Has anyone encountered weathered rock and it been an issue? Just want to know what we may be in for. We need to cut in around 2 metres at the worst point.

We also got an N3 wind rating, any idea on what this adds to the cost of a standard build.

Cheers

Thats bad news, if your site have rock bed around excavation area then get rock excavation. depends how deep it stays on your ground. good luck with your builder

Thanks Cameron 32

I just called the earthworks guy and he said it shouldn't be a problem as his equipment will chew through it, having said that I am still concerned.

I also went the house next door and he said he only had a problem on the other side of the house but it was quite easy on our side, still unsure as it is a bit of a gamble.

Depends what sort of rock and degree of weathering can vary from virtually soil to hard base bedrock.In the report did they give much of a description of the rock and were they able to drill into the rock or did their drill rig stop at a shallow depth?

Thanks Insider, I happened to be on the block when they were doing it. The report says 400mm but they did go deeper and he said it didn't seem very hard. On one he got down to about 700mm and this is an auger with a lawnmower engine. My concern is the likelihood on harder rock like basalt of or something. Saying they 300mm of the 400mm was top soil the developer put on top to hide it which according the drillers is common practice to sell the block nice and green...

Kaindec
I know what they are saying I have been bogged in that 300mm-400mm many times.
On the report they should state the geology so this could give you a glue.If it is basalt or granite you may hit very hard rock all of sudden if it is silt/mudstone not so bad.

Thanks Insider

Below is what the report said for all the bores - the auger didn't really stop they just stoped it when they realised it was rock, on one he showed me how far it would go which was about 700mm and seemed to come out a really fine grain

Depth (mm) Group Symbol
Soil Description
0 - 300 CL Silty clay, dark brown, with some gravels, moist, stiff 300 - 400 XW Weathered rock, grey, dry, hard 400 Termination of log. Auger refused due to weathered rock

As you said earlier, site going to cut 2m around worst point. biggest issue is leveling your site i think.

Cheers, the earthworks guy said he will chew through it, how do you mean about levelling the block?

Problem is that I am not sure who to believe, I can still pull out but don't want to.

I mean, if they cut your site to 2m deep then need a rock excavation. few house behind my street having rock beds, don't know what type of rocks, whole site sit above rocks(roughy 400mm from top and it goes more deep as well). i saw they use big machinerys and hammered more than two weeks time. that's really terrible.

Rock cost lots to excavate but is the best to build on. Your house will be "rock solid" no pun intended. It will not suffer any of the problems of cracking found in highly reactive clay sites.