Cheap injection underpinning; too good to be true?

[Overkill]

I am renovating a house that already has an extension on one side. The extension has a slab floor over clay sub-soil and it has subsided and moved about 10mm since it was constructed 30 years ago. I rang several companies about a structural inspection and one place said they could do a report for $1540 (seems about right) and chemical injection for $4180 - including the report.

The price is much lower than other forum members have mentioned ($7K to $10K) and they gave me the price over the phone without seeing the extent of the problem. I'd like to save some money, but this offer sounds a bit suspicious - how would I know if they are ripping me off with a temporary fix or a shoddy product? Do structural engineering companies have licensing I can check? Would customer referrals be worth asking for?

[Uncle Bob]

Sorry Overkill, I don't know the answer to your questions, but hate seeing a thread orphaned.

The only thing I can suggest is, will they offer a warranty?

[Overkill]

LOL I was feeling the cold! That's a very good point; I will check other firm's warranty period and if this crowd has a much shorter period or no warranty at all, that gives me clue about their reputation.

[Kinroh]

LOL I was feeling the cold! That's a very good point; I will check other firm's warranty period and if this crowd has a much shorter period or no warranty at all, that gives me clue about their reputation.

$4k/UP sounds about right to me. have you considered other options before underpinning? A concrete path surrounding the house, check for leaky down pipes and possible regrading of the ground. I dont think any firm will offer you a 100% guarantee that it will work, they can however say it will help reduce the amount of movement, and that youll have to accept cosmetic patching every now and then.

[Overkill]

I had the engineer out yesterday and he certainly knew his stuff! He had a heap of good advice about guttering and other drainage problems to fix to maintain the house in a stable condition and also said that if the foundations do ever need support the cheapest method will be digging a trench and pouring concrete, rather than any of the injection methods. Based on all that I'm happy to recommend this company for inspection services: SydneyWide Property Inspections/Conveyancing/Pre Purchase Inspections (http://www.sydneywidepropertyinspections.com/)