Do Cavity Walls Need Air Bricks?

Discovering damp patches or a musty smell within your home can trigger a concern. Often, these signs point towards poor ventilation in cavity walls—a common issue many homeowners face.

Air bricks serve as an essential fix to this problem by promoting airflow and reducing excess moisture.

From the basics of what air bricks are to their installation requirements, we cover everything you need for healthier cavity walls. 

Keep reading to find out more!

What are Air Bricks and Why Do We Need Them?

Air bricks are small, specially designed bricks with holes that allow air to flow through them. They are essential for providing ventilation in cavity walls to prevent moisture buildup and maintain the integrity of the structure.

What are cavity walls?

Cavity walls have a gap between two layers of brick or block to stop heat from leaving your home and help with sound insulation.

Importance of ventilation for cavity walls

Cavity walls need good airflow to prevent moisture build-up, which can lead to rot and mould. Ventilation lets the cavity breath, stopping condensation from damaging the inner wall.

Air bricks play a key role in this process. They allow fresh air to flow into cavities, helping to remove damp air and maintain indoor air quality. Without enough ventilation, the risks of structural damage increase due to excess moisture.

Fitting cavity trays above these bricks ensures extra protection against water entering living spaces.

When fitting air bricks in cavity walls, it’s crucial to adhere to regulations and consider proper installation for effective ventilation. Encouraging users to read more.

How to maintain adequate ventilation with insulation

To maintain adequate ventilation with insulation, consider installing cavity trays above air bricks in high-moisture areas to prevent structural damage. Using a telescopic duct or pre-fitted brick sleeve can help retain ventilation within the cavity walls.

Remember, sealing air bricks for heat efficiency could lead to increased moisture build-up and rot. Regularly inspect the air bricks to ensure they are not blocked or sealed, as this could compromise ventilation efficiency and lead to condensation issues.

Additionally, opt for plastic or clay air bricks from reliable suppliers like Strukta which offer various options suitable for your project’s requirements.


In conclusion, air bricks are crucial for maintaining ventilation in cavity walls to prevent dampness and rot in the building’s structure. It is important to ensure that these air bricks are not deliberately blocked or sealed off to maintain proper airflow and protect against potential issues with moisture.

Therefore, incorporating air bricks into cavity wall construction is essential for preserving the integrity and longevity of the building.

Cavity wall insulation can pose a risk to adequate ventilation if not properly managed, making it necessary to consider the placement and maintenance of air bricks during insulation installation.


Air bricks help keep the house fresh by letting air move through the cavity, stopping dampness and improving the effectiveness of your central heating and double glazing.

Yes, when you insulate a cavity wall, it’s important to check if you still need air bricks to manage moisture and ensure good ventilation, especially if you have MHRV (mechanical heat recovery ventilation) systems.

Installing new insulated windows can improve how well your home keeps heat inside and works with other features like vapour barriers in walls to control moisture without harming the insulation properties of your cavity walls.

You should install one air brick every 1.5m to 2m along the wall. This ensures your cavity wall insulation gets enough ventilation without losing energy efficiency. Proper airflow keeps damp and condensation away, making your home warmer and drier.

The NHBC Guidelines say to put these bricks at least 75mm above the ground. This helps avoid flood damage and keeps your suspended floors safe and dry. Always follow these rules for a healthier, more efficient home.