Basement PIV Unit Installation

A mid-terraced property in Manchester faced persistent issues with condensation and mould in its basement.

The occupants were concerned about high humidity levels, which posed a risk of decay and woodworm to the timber structures in the basement.

Our ventilation expert was called in to assess and rectify the situation.

Problem Identification:

Upon inspection, several ventilation issues were identified:

• Two air bricks at the front of the basement were blocked.
• Air bricks at the rear were covered by a concrete floor slab, part of an extension built many years earlier.
• The lack of adequate ventilation resulted in high humidity levels, contributing to condensation and mould growth.

Challenges:

The concrete extension floor slab prevented the creation of natural cross flow ventilation, a method often utilised to maintain low humidity levels. The inability to establish natural airflow from front to back of the basement necessitated an innovative solution.

Solution Development:

To address the ventilation problem without altering the rear extension, the following measures were implemented:

1. Mechanical and Natural Ventilation Integration:

• Two new double air brick vents were installed at the front of the property. These enabled fresh air to enter the basement and provided an exit for stale air.

2. Installation of a Positive Input Ventilation (PIV) Unit:

• A Flatmaster PIV unit was installed to introduce filtered air into the basement. This unit works by creating air pressure inside the space, effectively pushing the stale, damp air out through the new air brick vents. As a result, the unit facilitated a mechanical cross flow ventilation system.

Results:

The implementation of this combined mechanical and natural ventilation approach resulted in:

• A significant reduction in humidity levels within the basement.
• A noticeable decrease in condensation and mould, protecting the structural timber from decay and woodworm.
• Elimination of stale odours, providing a fresher air quality.
• Increased usability of basement space for storage without risk of damage by moisture.

Results:

The case illustrates the effectiveness of integrating mechanical ventilation solutions, like the PIV unit, with enhanced natural ventilation measures, even in constrained environments where traditional cross flow ventilation is not feasible.

This approach successfully resolved humidity issues, ensuring the basement became a safe and practical space for the occupants.

The project highlights the critical role of tailored ventilation solutions in maintaining healthy living spaces in challenging building configurations.