Tips & Tricks

Is Underpinning Required – Avoid a Ripoff

I was staggered this week. It was just unbelievable. Is underpinning even required?

A client came to me for a second opinion about a quote to underpin his residential property in Queensland. The quote was from a local builder for 25 underpins to an approximate depth of 2.5m in order to ‘stabilise’ a single level house.

The quote was based on an engineer’s assessment. A geotechnical engineer had also attended and provided the results of a soil investigation.

Both good signs.

So on the face of it, everything seemed legitimate. However, once I dug deeper the justification for spending so much money was very thin.

Very thin.

So very thin.

So how do you, as a homeowner, evaluate a quote for underpinning from a builder and determine if you’re likely to get value for money.

Let’s go through my independent assessment process together.

How We Got This Far

In this case, the dwelling was tenanted. Some cracks were identified and dutifully reported by the real estate agent from their periodic inspection.

The real estate agent recommended the owner get a quote from a local builder.

The builder engaged the geotechnical engineer to assess the ground conditions and a structural engineer to assess the cracks in the building.

So far, all very good. Excellent service and responsiveness and probably the correct course of action for an owner who does not reside at the property.

A note about the building history

The client advised that they purchased the dwelling in or around 2008 and subsequently lived in the dwelling for around one year.

The client had purchased a building and pest report (an excellent investment that even I, an experienced structural engineer, make use of when we purchase homes).
Some minor internal cracking was noted in the dwelling in the cornices and in some ceiling sheets.

OK. So even back in 2008 there was some minor cracking. The building hadn’t been painted since then so all good.

Strike One – The Engineer Wasn’t Registered

Alarm bells started ringing when the client sent me the structural engineer’s report.

The first thing I did was check that the author of the report was a registered engineer in Queensland (RPEQ). The Board of Engineers Queensland website allows anyone to check, really quickly, whether an engineer is registered to practice in Queensland. Here’s the link the BPEQ website:

This quick search indicated that the author WAS NOT a registered engineer.

That was strange. In fact, according to the BPEQ website, the consulting engineering services company that prepared the report did not have any listed RPEQ engineers.

Strike One

The report referred to the geotechnical report which appeared to have been commissioned concurrently.

Strike Two – The Damage Wasn’t Assessed Properly

The engineer’s report identified ‘several noticeable cracks’ but did not include any photographs of the damage or any indication of where the damage was located or any assessment of the crack width, length, severity or age.

This was a bizarre summary of damage given how much we, at Cornell Engineers, rely on crack location and width in order to determine the severity of the damage.

Indeed, the QBCC website even has this awesome Standards and Tolerances Guide which is meant to apply to brand new homes but has so much useful information for assessing older homes too.

The ‘engineer’ skipped over all those crack assessment steps and jumped straight to the floor level suvey.

Strike Three – The Floor Level Assessment Carried Too Much Weight

A floor-level survey is definitely one of our favourite and most powerful tools, but the assessment MUST be taken in context with the extent and age of damage.

Anyway, the engineer found that the floor was uneven, beyond the limits contained in AS2870:2011 (the current version of the footing and slab standard) and jumped straight into the UNDERPINNING!!!! stage.

Use an experienced engineer to determine if underpinning is required
How to use a water level to record floor levels
  • No assessment of the existing footings.
  • No assessment of the age of the damage.

Crazy. Lazy. Inexperienced. Unregistered. Bordering on fraud.

When Every Tool is Underpinning

You remember when, in my article, I wrote that “When underpinning is your only tool, every house looks like it needs underpinning.“?

This is exactly when that statement applies.

The ‘engineer’s’ client was a builder that constructs underpinning. Amazing how the solution to ‘fix’ this house was to underpin.

Is Underpinning Required?

So let’s assess whether underpinning is really required.

  • Was there one way, non-reversible subsidence of the footing? Yes, perhaps.
  • Was the slab heave caused by other issues such as broken pipes or trees? Not investigated.
  • Was the damage live and ongoing? Not investigated.
  • Could the damage have simply been repainted and plastered for the time being. Not investigated.

Look, the building was on a cut to fill site and the dropped area of the house was in the fill section. Maybe some underpinning is required.

But the fact that 25 underpins were recommended including in areas where there was no fill, no real movement, possibly not even any recent damage indicates that the underpinning assessment was premature and pretty much unfounded.

Underpinning Design Drawings

The real alarm bells sounded for me when I realised that the recommendation for 25 underpins was written into the engineer’s first and only investigation report.

How’s that for going from zero to one hundred?

All this is under the cover of an engineering report that was not even signed by an RPEQ engineer.

The Independent Assessment

So our independent assessment included these steps that you can do yourself.

Sometimes underpinning is the answer. But it is an expensive answer and sometimes there are other, cheaper, better options.

If in doubt ask lots of questions

If you receive an engineering report, engineering drawings, a builder’s quote or even verbal advice that seems strange, ask lots of questions. Find out the justification for the assessment. Some experts can explain issues better over the phone than they can write in a report.

If really in doubt – get a second opinion and an independent assessment from a qualified and experienced structural engineer….

Or just throw your money away on underpinning rip-off reports and quotes, but don’t say I didn’t warn you.