Underfloor Insulation and Ground Vapour Barriers. Is your home losing heat through the floors?
Many older homes in New Zealand were built on piles with little thought given to floor insulation or rising moisture from the ground. This can mean heat escaping through the floor and dampness creeping into your home.
A simple two-step approach can help. Underfloor insulation stops heat loss and cold air from moving up into your home. Ground vapour barriers reduce the moisture that can rise from the soil below your floor. Together, they help keep your home warmer, drier and healthier.
How underfloor insulation works
In winter, cold damp air can drift up through timber floorboards. Without insulation, this air cools the inside temperature and forces your heating to work harder, which increases running costs.
Underfloor insulation creates a thermal barrier between the warm air inside and the cold air below. It keeps warmth in and helps block cold air from rising through the floor.
What ground vapour barriers do
A ground vapour barrier is a heavy-duty plastic sheet laid over the soil under your home. It stops moisture in the ground from evaporating into the space below your floor.
Without this barrier, moisture from the soil can rise into the subfloor. This makes the space under your home damp, which can lead to problems such as:
- A musty smell
- Increased condensation on windows
- Mould growth
- Damage to timber framing or flooring
- Attracting pests
Installing a ground vapour barrier is straightforward. The sheet is laid across the bare soil, taped to the piles, and pinned in place. This reduces the amount of moisture entering the subfloor, helping to lower humidity inside your home. It’s a one-time job that can last for many years.
Why both are better together
Underfloor insulation and ground vapour barriers each tackle a different problem. Insulation reduces heat loss, blocks cold air and moisture. A vapour barrier reduces dampness and protects against rising moisture.
When both are installed, they help seal one of the main weak spots in older homes. The combination can be especially effective in areas with high rainfall, clay soil, or where the house sits low to the ground. Homeowners often notice improved comfort, lower energy use and better indoor air quality.
Checking your underfloor
If your home is older and built on piles, it’s worth looking under the floor. Many houses have damaged insulation or none at all. Damp ground is also common, especially in homes without a vapour barrier.
At Healthy Home Team, we work with trusted local providers to install both underfloor insulation and ground vapour barriers. We use quality materials that meet or exceed New Zealand standards and recommend the right solutions for your home.
Take the next step
If you don’t have underfloor insulation or a ground vapour barrier, we can help. These improvements can make a big difference to the warmth and comfort of your home.
Contact Healthy Home Team to arrange a free Healthy Home Assessment. We’ll check your underfloor and give you clear advice on the best way to reduce heat loss and dampness.