Maintaining a dry environment for your mattress and bed base is essential for a healthy sleeping space. When the underside of a mattress remains damp for an extended period, several negative consequences can arise: 

1. **Mould Formation**:                                           
A consistently damp mattress creates an ideal breeding ground for mould. This not only affects the mattress itself but can also pose health risks to those who sleep on it.

2. **Mould Stains and Unpleasant Odors**:   
Mould growth can lead to unsightly stains on  the mattress, detracting from its appearance  and hygiene. Additionally, the dampness can cause musty smells, making your sleeping area less inviting.

3. **Damage to Bed Base**: The type of bed base you have can influence the extent of damage caused by moisture. A wooden bed base is particularly susceptible to rotting in damp conditions. On the other hand, metal bed bases can start to rust, compromising their structural integrity. To ensure a comfortable and healthy sleeping environment, it’s crucial to address any sources of dampness and maintain proper airflow around your mattress and bed base.