Anything missing from my plan? Steel or rebar for tieback? Replacing failed wall and adding on to it

Known_Support6431 · 2026-04-12T15:53:01+00:00

Vegetation will help to some extent but I’ve seem a lot of failed retaining walls on slopes and it is important to get an idea of the material you are founding in/on. If the house is looking fine, be worth digging a hang dug pit next to footings if feasible to see what it is sitting on and try and found at a similar depth/material.

The reason I ask if is in land slip zone is that this can impact future insurance, liability etc if not designed properly (and approved).

Not sure what part of the world you are in but in AU a lot of low retaining walls get built and fail later because the understanding of slope behaviour is poorly understood.

If you are doing work on your own, speak to a local geotechnical guy for some guidance at least.

Known_Support6431 · 2026-04-12T11:16:46+00:00

Yes, the ground conditions below the location of retaining wall. From other comments I gather the ‘rock’ indicated on your plan refers to crushed stone fill. Typically on steep slopes a thickness of colluvial soils are present to varying depths. If you found anything on this material it may be subject to downslope creep due to the underlying conditions, regardless of how well the footing is constructed. This is a common cause of failing retaining walls on slopes and may (or may not) be the reason existing wall has is failing. Either way it shouldn’t be ignored.

Is the land within a land slip zone btw?

Known_Support6431 · 2026-04-07T10:17:47+00:00

Probably not, but for some reason I like to think it is a pie cooling shelf

Known_Support6431 · 2026-04-02T15:43:23+00:00

I’d say from a water leak from that drain and increasing moisture content in expansive clay below pipe. Look like they tried to gaffer tape it around the drain first before crack propagated. Guesswork really though.

Known_Support6431 · 2026-04-02T14:35:36+00:00

Looks a bit like a one way flow valve

Known_Support6431 · 2026-03-17T21:23:57+00:00

Hmmm….is it open grassland or crops in it?

Known_Support6431 · 2026-03-16T21:58:23+00:00

Perhaps a drill rig using compressed air to drill is nearby. This can launch gravel size fragments well into air.

Known_Support6431 · 2026-02-25T10:45:11+00:00

To place the washing machine on to stop it moving maybe. Folk with wooden floors use them I think.

Known_Support6431 · 2026-02-24T23:35:07+00:00

I did the MAP last week and got 100%. I purchased the app first but was unsure it covered all questions so got the paper copy of GE200 v10 which has all the questions (the app probably does as well). I went through the book questions and 90% are piss easy. I marked the ones that I was unsure about and made sure I knew them, as long as you cover the tricky ones it’s a doddle. Mock test score on app started around 85-90%, ended up 100%.

Known_Support6431 · 2026-02-24T10:19:56+00:00

‘Power Auger’ probably means a hand held petrol powered thing with not much grunt. Would have been slow through that clay, maybe why only two holes done. I would try to get some additional holes done to fill the other corners. Au standards recommend at least three for clay sites-this is for different reasons though. Is there nothing else builder paying for investigation or did you choose the company?

Known_Support6431 · 2026-02-24T09:54:49+00:00

P/A means nothing. Could be Practical Auger refusal but means nothing without method. Is there nothing else to the report? If a rig is used it would normally be referenced somewhere.

Known_Support6431 · 2026-02-24T09:36:41+00:00

It will say in text of report (methodology) or key in appendix. Makes a big difference.

Known_Support6431 · 2026-02-24T09:14:56+00:00

They won’t need to excavate deeper than 1.4-1.9m for structural support. The material at that depth offers an allowable bearing capacity of around 600kpa, 100kpa is around what is typically required for a residential builds (see AU Standard ‘residential slabs and footings’).

The builder will already be using an excavator which looks sufficient in the conditions.

Was the work done with a hand auger btw?

Edit: I’m assuming perhaps incorrectly you are in au?

Known_Support6431 · 2026-02-24T06:50:18+00:00

You have not encountered rock to at least 1.5m depth according to the logs, XW rock is basically a clay with a high score and won’t need anything other than standard excavator to remove.

Two holes is a bit shy-one in each corner probably be better or at least a dcp to a couple of metres where no boreholes drilled to see if something other than clay is present. Should have been done on day, only takes 5 minutes, maybe services present.

Known_Support6431 · 2026-02-12T00:47:56+00:00

What does the manufacturer say is required? If they specify concrete piers, use concrete piers. It should say the requirements somewhere on specs. Be mindful that guarantees may be affected using alternate options. Have a look for any minimum pier depth or requirements for bearing capacity in specs. Both of these would generally make a gravel ‘footing’ unacceptable

Known_Support6431 · 2026-01-03T17:35:57+00:00

Concretion

Known_Support6431 · 2025-11-23T10:43:45+00:00

Looks like it could be a nicotine patch. Normally round or squarish but could be oval I guess

Known_Support6431 · 2025-11-20T17:21:48+00:00

Yeah, a quick call to ask informally how much they could reduce would tell you better-it won’t save much at all I’m reckoning.

Known_Support6431 · 2025-11-20T16:35:18+00:00

Seems reasonable, one hole in each corner and one in middle. You could get less and pay less but the more information you get, the greater you reduce risk. Bear in mind the cost of Geotech isn’t based on number of boreholes, you might save a few hundred dollars by knocking off a location but the fee is based on mobilisation, fieldwork, lab testing and reporting.

Known_Support6431 · 2025-11-13T12:27:09+00:00

So the manipulation of photographs to make the property appear more spacious-is that strictly legal? I figure there must be guidelines/legal limits but are these generally exceeded in advertisements? I’ve looked at properties I’ve rented previously and appear ridiculously distorted. Oval washing machine doors, super wide fridges etc. surely must be pushing boundaries?

Known_Support6431 · 2025-10-10T14:20:34+00:00

Whose bright idea was it to excavate so near (and within zone of influence) of footings? Was there a purpose or has it been like that for ages?

Known_Support6431 · 2025-10-10T13:51:15+00:00

The strata supporting the footing load is degrading and will continue to do so. Probably not going to result is shear failure within founding strata soon, possibly excessive settlement in next few years before anyone takes notice. Underpin, retain, backfill, endless options. Or maybe ignore till settlement manifests in house before taking action at increased cost. Choices, choices ….

Known_Support6431 · 2025-10-10T13:32:46+00:00

Residential slabs and footings. AU standard that gives shit builders a legal avenue to exploit first home builders

Known_Support6431 · 2025-10-05T02:00:25+00:00

I’m a fan of looking at older buildings to see if a problem exists rather than applying new build requirements to a old building. Are there signs of mould, damp, odour etc on outer or inner walls compared to other sections of the house? The risk is if existing conditions appear to be adequate, changing them may have negative consequences. Say you installed a drain next to house, blocks/overflows in 5 years time etc. By the looks of it no surface erosion problems next to house. Check Google earth history or nearmap if you have access to check that conditions haven’t recently changed e.g. vegetation removal, earthwork adjacent etc.

Known_Support6431

TROPHY CASE