DIY Home Improvements Could Cost Homeowners Thousands — and Even Jeopardise a Sale
DIY Home Improvements Could Cost Homeowners Thousands — and Even Jeopardise a Sale
A North Shore real estate agent says he’s seeing a growing number of properties compromised by unconsented DIY work — a problem that’s now costing some homeowners tens of thousands to put right when they decide to sell.
Drew Miller of Ray White Mairangi Bay says a recent appraisal perfectly illustrated the issue.
“Last week, I met with a homeowner who wanted an updated market value for his property,” says Miller. “He’s a classic can-do Kiwi bloke — handy with the tools, loves improving his home. But what started as an appraisal quickly became a compliance check, because almost every ‘upgrade’ he’d done required either a Code Compliance Certificate (CCC) or a Certificate of Acceptance (COA).”
Miller says the owner had added a small in-ground pool under a deck, cut a carport into the hill, enclosed a garage with new internal stairs, and roofed over an outdoor entertaining area — all without formal consents.
“They looked fantastic and were clearly built with care,” Miller says. “But without inspection records or proof of footing depths, the council won’t issue retrospective CCCs. On a cross-lease title, enclosing space under a roof also means the flats plan is now technically defective — so the property can’t legally be sold as-is without disclosure.”
Rising COA Costs and Hidden Risks
Miller says the cost to obtain retrospective certification has climbed sharply, often catching owners off guard.
“A COA can run up to ten grand, and sometimes more if reports or engineering input are required,” he says. “That’s money most people didn’t budget for, especially when they’ve done the work themselves.”
One increasingly common issue, he says, is homeowners converting shower boxes to tiled showers. “Any waterproofing membrane system triggers the CCC process, but many people don’t realise that. They just swap it out and move on — until the buyer’s lawyer or bank flags it months later.”
Banks Are Tightening Too
“Buyers can be forgiving when things are disclosed properly and backed up by producer statements,” Miller says. “But banks aren’t. We’re seeing funding declined purely because of missing CCCs — which shrinks the buyer pool, limits competition, and can hurt the sale price.”
From a real estate perspective, Miller says, the issue isn’t about scaring homeowners — it’s about education.
“Our job is to help people protect their asset and avoid surprises. Disclose early, fix what you can, and know where you stand. Because when it comes time to sell, compliance equals confidence.”
Drew’s Three Tips for Homeowners
Check Before You Build
Call your local council before starting any work. Even small jobs like roofing over a deck or adding plumbing can require consent.
Keep Records
Retain receipts, plans, and photos for any work done. “Paper trails save headaches — especially if you need a COA later.”
Ask for a Compliance Review Before Selling
A pre-sale inspection or agent appraisal can identify potential red flags early. “Fixing issues before launch is always cheaper than dealing with them mid-campaign.”
For more information visit www.drewmiller.co.nz
ENDS.
CONTACT
Drew Miller
Licensee Salesperson
Ray White Mairangi Bay
M: 021 963 654
E: drew.miller@raywhite.com
ABOUT
Drew Miller is one of Auckland’s leading North Shore real estate agents, with more than 170 properties sold and over $187 million in total sales. A certified engineer and project manager by background, Drew brings technical expertise to every transaction, helping vendors navigate building compliance, disclosure, and risk with confidence.
Ray White Mairangi Bay sells homes across the North Shore and wider Auckland region using innovative marketing, data-driven strategy, and a passion for delivering premium results.