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Condensation in Basements

Mould in Basement
Waterproofing basements to prevent ground water ingress is only part of the story, albeit the first priority of course, but condensation must also be addressed if a basement space is to be considered ‘dry’ for habitation.

Fail to address condensation potential at your peril with the list of effects including mould, mildew and the obvious damage it causes to furniture, carpets, fixtures and fittings.

In basic terms condensation occurs when moisture laden warm air strikes a cold surface causing a transition from vapour to liquid water upon that surface. The atmospheric factors controlling condensation are air temperature (AT), relative humidity (RH) and surface temperatures within a space with the AT & RT fluctuations directly influencing ‘due point’.

Due point is point at which water vapour condenses to liquid water droplets and is expressed in °c.

When the surface temperature is at or below due point condensation is occurring.

Q: So now we know what condensation is, how do we deal with it?

A: Insulate and ventilate.


Insulating basement walls is all about preventing warm moist air reaching the cold basement walls and condensing. Sovereign are able to advise on insulating basements in conjunction with both the Sovdrain CDM and Hey’di K11 systems. Contact Technical on 01229 870800 for further information.


Providing adequate ventilation to basements can be a challenge as often just by the nature all walls are earth retaining and as such typical ventilation products cannot be used.

In the past occupants have used Dehumidifiers in an attempt to reduce the moisture in the air, however this is not a long-term solution and can be costly and requires routing emptying of the unit.

The answer is Positive Ventilation Systems (PVS)


Sovereign’s basement PV system The Concure 20/20 which is a wall mounted unit draws in fresh air via duct/pipe work. The air is filtered and dried; the dry air is then gently introduced into the basement area in a continuous manor which creates a positive pressure atmosphere which rapidly displaces moist stale air. The result

Clean, Healthy and Fresh Filtered Air into your basement.

For more information on any of the above please contact our technical support team on 01229 870800 for further information