Rising Damp Specialists White Logo

Sub Floor Ventilation Sydney

Rising Damp Specialists White Logo

Sub Floor Ventilation Solutions Sydney

The Rising Damp Specialists
Ask For Jason: 0474 499 309

The Rising Damp Specialists

Subfloor Ventilation Fans

Rising Damp Specialists White Logo

You don't always need sub-floor ventilation fans (but sometimes you may).

Sub-floor ventilation fans are very effective for removing mould, damp smells and drying excessively damp earth below your building, but there are a few things you should know before installing them.

Installing Sub floor fans sounds like a “great idea” to cure rising damp. After all, the walls are wet so why not just dry them out with fresh air?

If you have rising damp, installing fans will likely accelerate the damage that rising damp causes. Speeding up the evaporation of water from the masonry will deteriorate the bricks and mortar below your floors FASTER, turning them to dust.


Because rising damp is just as much about salt as it is about water. 

Let’s define “Rising Damp” by saying what rising damp is NOT. 

  • Rising damp is not damp smells. (you can have rising damp with or without damp smells)
  • Rising damp is not mould. (You can have mould with or without mould)
  • Rising damp is not rotting bearers and joists in your floor.

Rising damp SPECIFICALLY is the capillary action of water containing minerals, through masonry to an evaporation point. 

It is called Rising Damp because as the water rises up the walls to the evaporation point, the water evaporates at the lowest point (path of lease resistance). As the pores of the masonry block with salts the water will go a little bit higher to evaporate more easily. As the pores of the masonry become filled with salt, the water creeps up the wall until gravity prevents it rising any further, then the salts will start to accumulate below the maximum rising damp height which is limited by gravity. 


how salt damages walls - efflorescence


It LOOKS LIKE sub floor fans fix rising damp because the fans cause the evaporation of the water from the masonry BELOW the floors so you cant see the symptoms of the rising damp any longer. Essentially out of sight, out of mind. 

Unfortunately “what you cant see won’t hurt you” doesn’t apply in this situation. 

Watch the video below to see what can happen in the worst case scenario. 


This page is not here to fill you with fear. It is here to show you ALL the outcomes that can happen when you install sub-floor fans.

After telling you all the things that can go wrong with sub-floor fans. Sometimes a house needs sub-floor fans. Sometimes there is a lot of mould and damp smells. Sometimes the timber bearers and joists are rotting. 

We do install sub-floor fans when people REALLY need them, but they can damage houses so we are cautious about installing them.

Sometimes the only solution to a dampness and mould issue in a building is to install sub-floor fans.

There are ways to prevent the excessive evaporation from causing structural damage to the subfloor walls and piers of your house and we can advise you about what you can do to prevent the fans damaging your subfloor masonry if you need to have fans installed.

efflorescence in masonry brick
  • Enter your details now
    & get a call-back.

  • (This helps me know what kind of house you have)
  • (This helps me know the cause of your rising damp)
  • (This helps me know which rising damp solution is best)

P.S. I can get pretty busy during the day so if you cant get through by phone then please use the form on this website (it’s a little easier for me to keep track of).


Rising Damp Solutions Sydney
Spalling Brick Treatment 
Eastern Suburbs
Lower Northern Beaches
Lower North Shore
Sydney Metro
Inner West
Concrete Slab Lifting

Our hours

07:00 – 18.00
Monday – Saturday

Contact us

Phone: 0474 499 309