Understanding Condensation Malcolm Thornton Managing Director, Proten Services

What is the PCA? The Property Care Association (PCA) is the trade association representing members, promoting best practice and providing technical guidance in the following sectors: Damp control Timber preservation Waterproofing Structural repair Invasive weed control (including Japanese knotweed) Flood recovery Flood protection, resistance and resilience Members include: Contractors Surveyors Manufacturers and Distributors Consultants The PCA has been in formation for 85 years, formerly the British Wood Preserving and Damp-proofing Association. We currently have over 450 members.

Contractors and surveyors specialising in:  Damp Proofing  Timber treatment  Condensation  Basement Waterproofing  Structural Repair  Concrete Repair  Protection from the Environment Who are Proten Services?

Types of Damp RISING DAMP Rises up from ground (therefore only occurs at ground level) Tide marks appearing on a wall to a height of 1m approx Occurs if damp course is bridged, damaged or none existent PENETRATING DAMP Enters through the property at any height Often due to poor property maintenance eg blocked gutters, cracked render CONDENSATION Imbalance of airflow, heating & ventilation Can occur throughout the home Black mould, streaming windows, musty smell, damage to home contents, health implications WATERLEAKS & FLOODING Ongoing leaks from pipes which have gone undetected Changing weather patterns & environmental factors leading to increased risk of flooding WATER PRESSURE AFFECTING BASEMENTS & CELLARS Dampness and flooding to underground structures caused by groundwater pressure

What should landlords look out for? Visual evidence Mould growth Deterioration of finishes, blowing/disintegrating plasterwork Liquid water on surfaces Staining of finishes Efflorescent salts on surfaces Timber decay Distorted timbers Dampness to finishes

Common Faults Other Defects Ground Water Rainwater goods Rising Damp Blocked Gullies

Condensation We will look at: What is condensation? How and why does it form in buildings? Types of condensation How we identify a condensation problem How condensation affects occupation Remedies

What is Condensation? Condensation occurs when water changes from its ‘gaseous state’ to its ‘liquid state’. This only happens when the air reaches a relative humidity of 100% The point at which the water changes state as saturation occurs is known as the ‘Dew Point’

Condensation Condensation is deposited on any surface that is below the Dew Point.

Condensation All air contains some water vapour The amount of water that can be held in the air is dependent on the temperature The higher the temperature, the more water can be held in the air Surfaces are usually cooler than the air that surrounds them If these surfaces are cooler than the dew point, then the water will condense out of the air

Surface Condensation

Condensation The condensation problem is mainly seasonal. Most problems happen between October and April each year. If there are persistent problems with dampness outside the period, it is unlikely to be condensation.

Condensation can be deposited at the surface and is known as ‘surface condensation’ Or within a structure where it is called ‘interstitial condensation’

Interstitial Condensation Condensation that occurs within a structure This can be very difficult to diagnose and is relatively uncommon.

Interstitial Condensation Inside Wall temperature gradient Dew point temperature gradient Interstitial condensation Outside

Height of Rise (1) Air at 10⁰C can hold a max. of 7.6g water vapour/kg dry air Air at 20⁰C can hold a max. of 14.7g water vapour/kg dry air It is therefore useful to know how saturated the air is with water vapour This is the RELATIVE HUMIDITY So we can say: The amount of water vapour in the atmosphere at any given temperature expressed as a percentage of the maximum amount of water vapour that can be held at the same temperature = RELATIVE HUMIDITY RELATIVE HUMIDITY is therefore a PROPORTION, NOT AN AMOUNT!

Effects of cooling air on Relative humidity (rh) 60% RH83%RH100%RH 20 ⁰C 15 ⁰C 12 ⁰C

Where is the water from? Atmospheric water coming out of its gaseous state. Water is released in the air from a number of sources associates with normal life and occupation.

Moisture Production Per Day MOISTURE PRODUCTION PER DAY (Average dwelling, 4-5 people) ACTIVITY MOISTURE PRODUCTION Washing & bathing 0.4 – 0.5l Drying clothes 4.0 – 5.0l Washing clothes 4.0 – 4.5l Washing up 0.8 – 1.0l Cooking 2.3 – 2.8l 2 people active (16 hours) 1.5 – 1.7l 4-5 people asleep (8 hours) 1.3 – 1.6l TOTAL: 14.3 – 17.1l

Does rising or penetrating damp contribution to condensation? If condensation is occurring the walls will be relatively cold. If the walls are cold then significant evaporation is unlikely. Water from rising or penetrating damp is very unlikely to contribute significantly to a condensation problem.

Diagnosis and Investigation The best plans for remediation are based on a good understanding of the problems – the specialist must therefore:- Survey Research Communicate Open up Sample Measure Observe Record

Diagnosis and Investigation Obvious evidence of condensation problems: Mould Growth on walls ceilings Musty Smell Fungal Growth Water droplets on impervious surfaces Steamed up windows Decay to internal sections of timber window frames

The significance of mould & health Is mould associated with condensation a health hazard?

The role of the building System built flats Typical Bungalow Steel clad house High Rise flats

Heating

Combating Condensation Improve ventilation – sweeps out moisture laden air and replaces with drier air from outside Improve heating – make it constant, not intermittent Reduce sources of moisture – clothes drying/cooking/bathing Improve thermal properties of walls – keep dry (silicone?) Dehumidifiers? Improve surface temperatures – insulate Ongoing condensation?

Combating Condensation Passive stack ventilation Positive pressure ventilation solution Vericure With ventilation

What do we at Proten Services recommend to cure persistent condensation? Condensation Survey Vericure Range of Positive Pressure Condensation Control Units and Extractor Fans Units work by creating a slight positive pressure which forces moisture laden air out of the property and replaces contaminated air with fresh, filtered dry air Powerful, low energy and can start to cure condensation within two days of installation Various units available to suit all property types Energy positive with low running costs of around 2p per day No maintenance required other than replacing filters every 3-5 years Operates continuously & automatically and quietly with no attention required from occupants

Combating Condensation Other Remedies Mould removers and anti mould chemicals Anti mould Paints Other building solutions can be effective against mould growth

Don’t guess! Get expert advice!!

Further information: Contact: Questions?