Why Soil Against Your House Wall is a Concern for Sydney Homebuyers

Purchasing a home in Sydney is an exciting yet stressful time. As you view potential properties, one issue you must look out for is soil building up against the external walls. This seemingly small problem can lead to some hugely expensive repair bills down the track if left unchecked. That’s why getting a pre-purchase building inspection is so important before signing on the dotted line.

In this article, we’ll explain what soil against walls means, the main problems it causes, and why it should be a major red flag for Sydney home buyers. Read on to learn why you need to take this seriously to avoid massive headaches after moving in.

What is Soil Building Up Against the Walls?

When soil, mulch, or garden beds are built up against the external walls of a home, it basically means there is no gap between the wall surface and the ground. The soil, mulch or plants are touching or pushing directly against the walls.

Sometimes, the previous owners have purposefully backfilled garden beds or soil against the walls for landscaping purposes. Other times, the soil has naturally washed against the foundations over the years and accumulated.

Why is This a Problem?

While it might seem harmless, soil building up against walls can lead to some hugely expensive issues down the track. Here are some of the main problems it causes:

  • Rising damp – when moisture from the soil seeps into the walls through cracks and mortar holes, leading to dampness inside, mold, and deterioration of the walls.
  • Foundation movement – soil pushes against the walls and foundations, causing cracking, subsidence, and structural instability.
  • Pest access – termites and other pests gain easy access from the soil into wall cavities and can quickly cause damage.
  • Wall deterioration – soil causes the base of walls to rot and degrade quicker, especially in older homes.
  • Drainage issues – soil prevents proper drainage around the home, leading to flooding, erosion, and water ingress.
  • Difficult maintenance – can’t access or paint walls properly, weed removal problematic.

In summary, soil against walls kickstarts a cascade of maintenance nightmares and destroys the structural integrity of a home from the ground up.

Why Sydney Home Buyers Must Take Notice

Sydney faces unique challenges when it comes to soil against walls due to its hot, wet climate and terrain. Here’s why it’s such a big deal:

  • High rainfall – Sydney gets over 1200mm of rain per year on average. This heavy moisture helps rising damp spread quickly through walls.
  • Clay soil types – Sydney basin clay soils expand and contract a lot compared to other soil types, causing more movement against walls.
  • Older homes – Sydney has many old cottages and villas with deterioration risks. Soil accelerates the decay of brick/stone walls.
  • Costly repairs – Sydney’s high labor and material costs make any repairs extremely expensive. Rising damp alone can cost $10,000+ to fix.
  • Pest heaven – Sydney’s climate allows termites and borers to flourish. Soil gives them an open invite into your home.
  • High property prices – you want to protect your valuable asset. Soil damage could significantly devalue a property.

Considering these factors, no Sydney buyer can afford to ignore the issue of soil against the walls, both for damage prevention and maintaining the home’s value.


Soil building up against external walls may seem like a trivial issue at first, but for home buyers in Sydney, it should be a major red flag. The combination of heavy rain, clay soils, old housing, and pests create the perfect storm for exponential damage over time. Left unchecked, the costs to fix the ensuing structural and damp issues can spiral out of control.

That’s why getting a thorough pre-purchase building inspection is so critical before purchasing any Sydney property. Look for an experienced inspector who will clearly identify any soil against wall problems or risks. This small step can save you a huge amount of money and heartache down the track as a homeowner.