The Condensation Trap

Is It Possible To Prove That Tenant Behavior Is The Prime Cause of Condensation Damp?

Chronic cold surface condensation in a Wimpey No-fines non-traditional property

Chronic cold surface condensation in a Wimpey No-fines non-traditional property

Many landlords still hold the view that where a diagnosis for condensation damp has been made then the assumption can safely be made that occupants are responsible, but how do you prove an occupancy related issue?
Is it enough to note that the tenant was drying washing indoors, had extractor fans turned off or perhaps they weren’t using their heating due to fuel poverty? The simple answer is no, because none of those facts, however valid, deal with the landlords obligations.

In fact there is no known test that can prove that residents cause condensation damp; rather you can only prove this by a process of elimination and exclusion of all other factors. Landlords need to work backwards and first prove that they have complied with their own obligations; they should first ask themselves three key questions:

1. Is the property dry and well insulated?

2. Have we provided an effective means of mechanical ventilation?

3. Have we installed a fully controllable heating system?

A point often overlooked is the requirement to prove that the building fabric is dry. If it is wet then moisture evaporating from the building fabric can add to internal relative humidity levels. Moreover, wet building fabric has a much-reduced thermal value and so is harder to keep heated above dew point temperature. Wet building fabric can be the prime cause of a secondary condensation damp problem and this is often missed. Opening windows is never a good idea and we have been battling this bad advice for years. Telling residents to open up windows and turn up the heating is clearly counter-intuitive. The requirement for a fully controllable heating system ensures that the resident has the ability to adjust room temperatures in every room.

Poorly insulated bathroom bulkhead. If mould forms here is this an occupancy issue?

Poorly insulated bathroom bulkhead. If mould forms here is this an occupancy issue?

If Landlords are confident that they have complied with all three factors then by a process of elimination they can safely arrive at the conclusion that occupancy issues are to blame. Unfortunately the default position we often encounter is that residents are to blame, even in the absence of any meaningful evidence.

Our own pragmatic view formed on the back of hundreds of damp surveys and numerous expert witness cases is that occupants cause humidity but buildings cause condensation.

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