How to solve Condensation

What is Condensation?

When warm, moist air comes into contact with either a surface or air that is colder than it is, the warm air is unable to retain the same amount of moisture as it did and the water is released either into the cold air or onto the colder surface, causing condensation to form, quickly followed by mould. The air contains moisture. The temperature of the air determines how much moisture it can hold, and warm air contains more moisture than cold air.

What are the Causes?

Day-to-day activities such as cooking, washing and drying clothes, heating and even breathing produce water vapour. Air can only hold so much moisture in the form of an invisible vapour, no matter what temperature it is.

When the air contains more moisture than it can hold, it reaches ‘saturation point’ and when this is reached, the moisture turns back into water and condensation occurs. The temperature reached at saturation point is called the ‘dew point’.

When this happens, the air has a relative humidity of 100%. The air in the majority of homes tends to have 50-70% relative humidity. Problems occur when structural defects in a building mean the moisture content has become too high; when old houses have no damp-proof course (DPC); and when there is inadequate ventilation in the home.

Period homes often have no DPC, which means moisture from the soil beneath the house rises up into ground floor rooms, whilst other homes suffer from bridged DPCs or damaged guttering.

There are several types of condensation. Cold-bridge condensation occurs when warm, moisture-heavy air comes into contact with surfaces at or below its dew point. This occurs at the base of external walls – where it is often mistaken for rising damp – on windows, where it may cause cills to rot, and on the underside of the roof.

Warm-front condensation occurs when warm, damp air gets into a cold house. This happens in the winter, when a ‘warm front’ from the Atlantic arrives, and is common in unoccupied houses.

Interstitial condensation happens when warm, moist air diffuses into a vapour-permeable material, such as fibrous insulation. If this material is warm on one side and cold on the other, the moisture will be deposited in liquid form within the material. This is a particular problem in heavily insulated or air-conditioned homes.

How to Treat it

There are three basic ways to control the problem of condensation, by looking at relative humidity, ventilation and insulation:

• Control the relative humidity in your home through the use of extractor fans in kitchens and bathrooms. Shutting the doors to these rooms whilst the extractor fans work also helps
• Ensure there is adequate ventilation. Trickle vents in windows work well, but a more sophisticated option is a heat-recovery ventilation unit. These replace the air in your home by taking the stale, damp air outside, then bring fresh air back in via a separate grille, passing it back over the heat exchanger to be warmed. It is also possible to buy central extract systems which connect all of the wet areas in your home to a central fan before discharging the stale, moist air outside
• Add insulation so that internal walls are kept at a temperature above the dew point of the air inside

C & L Windows and Conservatories Ltd

65, Seymour Road
Gloucester
Gloucestershire
GL1 5PT

www.candlwindows.co.uk

01452 526028

Conservatories are the way forward!

Conservatories not only offer versatile accommodation, they are also the cheapest route to extra living space in your home and can be built far more quickly than a full-blown extension. 

Some dos and don’ts to get you thinking:

• Do your research – make sure you are buying the best quality structure within your budget
• Do make sure you ask your builder what is included in his quote – is it inclusive of flooring and electrics or will you be left with a bare shell?
• Do install effective heating and ventilation arrangements so that you can use it in all seasons
• Do check out whether you need planning permission or building regulations approval if you go ahead without it you may have to take it down
• Do think about the position of your conservatory – if it’s south facing it will need good ventilation and shade, if it’s north facing it will need efficient heating
• Don’t try and build your own conservatory
• Don’t add a conservatory if it is going to take up too much space in the garden
• Don’t choose a design which is not in keeping with your house

Planning & Building regulations
There is generally no requirement for conservatories to meet Building Regulations in England and Wales if they are separated from the rest of the house, for example by patio doors, the floor area does not exceed 30 square metres and it is not permanently heated. It is advisable to check with your local authority because other restrictions may apply in your area.

Structurally speaking – how’s it made?
Most conservatories will have a concrete foundation and floor slab, cavity brickwork lower walls with glazed upper walls and roof panels set within a framing system. A number of materials can be used for framing, uPVC being the most economical and therefore most commonly used, with aluminium, steel and timber offering alternative options. All will provide a good result, but achieving watertight joints with timber is more dependent on the skill of the installer, and uPVC may not be allowed on listed buildings or in conservation areas.

Glass facts for conservatories:

• Safety: For safety, toughened or laminated glass must be used throughout. Laminated glass offers added security benefits against break-ins and cuts out around 90% of the sun’s UV rays, which fade furnishings.
• Stay cool: To prevent overheating, particularly if your conservatory faces south, use solar control glass or bronze poly carbonate panels for the roof. This can reduce the temperature by several degrees in the summer as well as reducing glare.
• Some conservatory roof systems have ridge ventilation and roof lights that open automatically above a given temperature to allow air to circulate. You should also consider the position of windows and doors to allow a cross flow of air when open.
• Winter warmer: Fitting low-emissivity glass will add just two or three hundred pounds to the bill but significantly reduces heat loss during winter.
• Noise reduction: Glass offers dramatically improved sound reduction compared to 25mm poly carbonate sheets. Polycarbonate roof panels may be less expensive, but they are far noisier than glass when it rains, and can be real conversation stoppers in a downpour. If you want to use your conservatory as a main living room it is worth paying extra for a glass roof

www.candlwindows.co.uk 

C & L Windows and Conservatories Ltd

65, Seymour Road

Gloucester

Gloucestershire

01452 526028