5 Design Mistakes New Property Investors Make (That Cost Them Thousands)

Written By TB ARCH PTY LTD

Introduction

Thinking of adding a granny flat, subdividing, or renovating a rental?

Property investment isn’t just about buying cheap and building fast — poor planning and design mistakes can eat away your profit or trap you in council delays.

This quick guide outlines 5 mistakes new investors make that cost money, time, or future resale value — and how you can avoid them.

The Mistakes

1: Designing Without an Exit Strategy

Many new investors design for today — not for sale, rental, or refinance tomorrow.
Tip: Design with valuation in mind. Prioritise legal room sizes, dual access layouts, and compliance that banks and buyers trust.

2: Ignoring Planning Restrictions

Not every lot can take a granny flat or second dwelling — setbacks, open space, and overlays can block your plans.
Tip: Get a planning check before you design. A quick feasibility report can save you months.

3: Overspending on Non-Essential Features

Many first-time investors burn cash on oversized kitchens, fancy finishes, or overbuilt bathrooms — that don’t add value to rent or sale.
Tip: Invest where it returns: separate entries, extra storage, minimum compliance sizes. Avoid ego-building.

4: Using Cheap Drafters Without Compliance Knowledge

Plans drawn by someone without NCC or R-Codes experience might be cheaper — until council rejects them.
Tip: Always work with a qualified building designer who knows local regulations, and can prepare drawings ready for approval.

5: Poor Layout for Tenant or Buyer Use

Bad flow, dark rooms, or awkward bathrooms kill rental yield and resale.
Tip: Maximise light, privacy, and storage. Small upgrades in layout lead to big value at the bank or the open home.

Next Step – Start with a Feasibility Consultation

Not sure if your property can take a second dwelling, new layout, or value uplift?

Tay Bui Arch Studio offers a paid Site Inspection & Briefing to help you:

✅ Check zoning, setbacks & constraints
✅ Get practical layout advice
✅ Receive a short report outlining what’s possible

Fee: $299 (credited if you proceed with full design)

👉 Book today at taybuiarch.com.au/contact or email tay.bui@taybuiarch.com.au

TB ARCH PTY LTD

Precision. Clarity. Design with purpose.

tbarch. is a boutique architectural and advisory practice based in Perth.

We specialise in residential design, alterations, infill development, granny flats, and complex approvals across Western Australia.

Our approach is simple:

Design with intent.

Document with accuracy.

Deliver with discipline.

With experience spanning custom homes, extensions, subdivisions, and compliance-led projects, we focus on solving constraints early and creating design outcomes that are practical, refined, and aligned with local regulations.

We work closely with surveyors, engineers, planners, and builders to provide a complete service from concept to approval. The goal is not bigger design. It is better design; functional, efficient, and tailored to each site.

Every project receives a considered process, clear communication, and a standard of detail normally found in larger studios.

Our scale allows us to stay selective and maintain high-quality work.

If you are planning to extend, develop, subdivide, or improve your property, we provide the expertise and structure to make the path forward clear.

Thoughtful architecture.

Accurate documentation.

A smoother approval journey.

https://taybuiarch.com.au
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5 Design Mistakes Kill Your Home’s Resale Value (& How to Avoid Them)