A Ngaio couple asked me to look at a retaining wall on a section they were about to list for sale. The wall looked fine. What worried the eventual buyer’s lawyer wasn’t the wall itself – it was that nobody could produce a consent, a code compliance certificate, or so much as an invoice for it. The wall had probably been built properly. Nobody could prove it, and in a property transaction, unprovable is treated the same as undone.
The paper that outdoor work needs to have
For anything that required a building consent – most retaining walls over 1.5 metres, and some lower ones depending on what they support – you need the consent itself and the code compliance certificate, or CCC, confirming the finished work was signed off. Keep the design drawings, and if the wall or earthworks involved a geotechnical report, keep that too; it’s often the only record of what the ground actually looked like before the work covered it up. Add materials dockets and warranty documents for anything with a manufacturer warranty, such as a specific waterproofing membrane or a proprietary drainage product, and keep the invoices from the contractor, itemised rather than a single lump sum.
Photograph what’s about to disappear
The most valuable photos on any outdoor job are the ones taken right before something gets covered over: the base course before paving, the reinforcing steel before the concrete pour, the subsoil drain before backfill goes over it. Once soil is back in the ground, that evidence is gone for good, and a buyer’s inspector five years later has no way to check it existed. A dozen photos taken at the right moments, dated and kept with the invoices, are worth more than any amount of written description after the fact.
Where this ends up in a sale
A building consent and its CCC show up on the Land Information Memorandum, or LIM, that any serious buyer orders from the council before settlement. A structure with no consent on record where one should exist is a flag a buyer’s solicitor will raise, and it routinely gets reflected in the price – sometimes as a straight deduction to cover the cost of a certificate of acceptance after the fact, sometimes as a condition of sale requiring the seller to sort it before settlement. An undocumented retaining wall doesn’t necessarily fail; it just gets discounted, because the buyer is now pricing in the risk you could have removed with a folder of paperwork.
A filing system that actually survives ten years
It doesn’t need to be complicated. One folder per structure – wall, deck, driveway, drainage – containing the consent, CCC, design drawings, key construction photos, and invoices, kept as PDFs somewhere that will still exist when you come to sell: a cloud drive, not just a phone’s camera roll that gets replaced. Note the date and contractor for each item as you go, while you can still remember it, rather than trying to reconstruct it from memory when an agent asks for it years later. It’s worth doing this while the work is fresh in mind rather than treating it as paperwork for later, because the gap between finishing a job and needing the file again is usually measured in years, not months, and memory fades faster than a folder does.
What a council inspection record adds to this
Inspection records sit alongside the CCC as part of the same paper trail, confirming which stages of the build a council inspector actually checked rather than just signed off on paper. Knowing what typically gets checked helps you know what to photograph before the inspector arrives – see what council inspections cover for outdoor work for the stages that matter most. MBIE’s page on code compliance certificates and consent records explains what a CCC actually confirms and why it matters at resale.
Frequently asked questions
What records should I keep for a retaining wall or deck? The building consent, the code compliance certificate, design drawings, any geotechnical report, itemised invoices, and photos taken before backfill or concrete covers the work.
Does a retaining wall without a consent affect a house sale? Yes. It shows up as a gap on the LIM report and buyers’ solicitors typically flag it, which often leads to a price adjustment or a condition requiring it be resolved before settlement.
What is a code compliance certificate? It’s the council’s confirmation that consented building work was completed in accordance with the consent, and it’s one of the first documents a buyer’s solicitor checks for.