Condensation

Condensation

Call back request

Condensation and mould growth

Condensation in a property is usually a direct result of the ‘life style’ of its occupants. In other words it is how we live in our properties  i.e. the frequency, amount and type of heat used combined with what we do that produces water vapour that might eventually end up as condensation on windows and walls causing mould growth and a musty smell

The Problem

Condensation is by far the most common cause of dampness in buildings, probably accounting for most dampness problems reported. It affects both old and new properties.

Condensation is directly associated with mould growth, and it is this that the occupier first sees and gives an idea as to the potential scale of the problem. The mould is usually found on decorative surfaces, especially wallpapers, where it can cause severe and permanent spoiling. The mould and its spores (‘seeds ’) cause the ‘musty’ odour frequently associated with a damp house and can sometimes give rise to health problems.

The obvious places or condensation to occur are on cold walls and floors, but sometimes it occurs in roof spaces and in sub floor areas where there is a suspended floor. Timbers in these areas will become damp and susceptible to damage by dry rot or wet rot.

It is a fact that warm air can hold more water as vapour than cool air. So, quite simply, condensation is caused when moisture-laden air comes into contact with a cold surface –the air is cooled to a point where it can no longer hold its burden of water vapour. At this point, (DEWPOINT), water begins to drop out of the air, and it is seen as condensation on surfaces. On impervious surfaces such as glass and paint, beads or a film of water collect, but on permeable surfaces such as wallpapered and porous plaster the condensing water is absorbed into the material. Therefore, the problem is initially not obvious.

Recognising Condensation

Condensation is very much a seasonal problem, occurring during the colder months (October to April). During the summer the problem is seen to go away. During the winter, ventilation of the house is usually low (windows and doors are closed, draught proofing takes place.) This allows build up of water vapour in the house, which, in some cases, is sufficient to cause condensation. So during the colder months the following signs begin to appear:

• Water droplets form on cold impervious surfaces such as glass and paint

• Slightly damp wallpaper (often not noticed)

• Development of moulds, usually black mould (Aspergillus niger). This frequently forms in areas where there is little air movement such as window reveals, floor/wall and floor/ceiling junctions, behind furniture against colder walls and in the classic triangular pattern in corners. Where the problem is very severe, water will even collect and remain on double-glazing.

In some cases, condensation may be long term but intermittent, forming only at certain times of the day or night. In these cases the only sign of condensation, may be mould growth, water perhaps evaporating during the day. One should also be aware that the problem can occur well away from the site of most water vapour production. For example, water vapour produced in a kitchen may diffuse through the house into a cold bedroom where it will condense on cool walls and lead to mould growth.

Mould growth (Aspergillus niger)

The greatest problem with long-term condensation is the associated mould growth, most frequently visible as black spot mould.

Mould spores are present generally in the atmosphere, usually at relatively low levels. Under normal circumstances they cause no problem, surfaces being too dry for their generation and growth. However, should they land on a wet surface (condensation) under humid conditions, then they will germinate and develop into heavy mould growth, with the inevitable release of vast numbers of spores. Not only does this cause decorative spoiling, but, in some cases, health of occupants may also be affected.

Note that Black Mould can only flourish on the pure water associated with condensation Black Mould is not an indication of rising damp

For a more in depth look at condensation you can visit www.specifypga.com

The Solution = Positive Input Ventilation (PIV)

A positive input ventilation unit gently supplies tempered, filtered air into a home using otherwise unused heat within a roof.

The benefits of this are enormous;

•    Firstly, it means that a significant proportion of external pollutants are prevented from entering the home.

•    Secondly, the use of the otherwise unused heat in the roof results in the ventilation unit providing a significant net energy gain to the home.

•    Thirdly, there is no better way to ventilate a home than from the inside out via a single, centrally located, supply air diffuser.

Damp Proofing Blog

Condensation

Damp Proofing — Saturday, August 02, 2014

Condensation moisture in the air can come from a variety of sources in your property. In your property normal day to day activities create water vapour which can lead to condensation in the property.

When warm air meets cold air the air is reduced below its saturation point and as a result water vapour turns from a gas into a liquid. This can be visually observed on window sills, tiles etc. This is known as surface condensation.

There are a variety of condensation types including condensation that can occur within the internal fabric of the building.

Interstitial condensation

As you can observe from the diagram above interstitial condensation is result of the temperature inside a building versus outside the building coming into contact and the air inside a building is at a higher temperature than the external air. This results in higher pressure forcing the warm air through the structure including the moisture from the inside the home. When the air that is warm and moist cools below its dew point, within the fabric of the building, this forms condensation.

This type of condensation can contribute to:

  • Structural damage.
  • Timber decay.
  • Reduce cost of your property.

Conditions for Condensation — The time of year!

When we enter winter this is the season zone where an increase in warm moist air in the home is increased and as it colder outside condensation can arise

Types of homes and condensation

Timber frame buildings:

These homes are at risk of interstitial condensation and may benefit from an impermeable roofing to prevent water vapour coming into contact with the cladding.

Traditionally designed homes:

Homes that have a flat or decked room have been observed to be a target of condensations. Implementing a barrier on the roof membrane can reduce the impact that condensation can have. This prevents the water vapour from permeating the external environment.

Brick homes

Homes that have brick cavities are susceptible to interstitial condensation with moisture within the home coming into contact with the external cold air and reaching the dew point.

The Causes of Condensation

In dwelling houses condensation is related to modern living standards, economic pressure and change in building design.

Moist air can be a result of everyday activities including cooking, bathing, washing and drying clothes. Certain areas of the home produce moisture more than others including bathrooms and kitchens where moist, warm air can then spread to cooler parts of the house to condense on cold surfaces.

If a home has a great level of ventilation then the risk of condensation decreases. In the past homes were able to produce ventilation more easily due to the limited use of double glazing windows, and open fire places. However in the current world we seal up our properties with an increase in central heating and full-sealed windows.

A level of consistency is required for ventilation to be effective.

Economic Pressure

Due to our current economic situation this has resulted in individual selectively heating rooms and using paraffin heaters to reduce costs. This can increase the level of moisture and result in an increase in condensation.

Mould Growth

Where does it occur?

This can occur on damp surfaces including plaster, wallpaper and has a high level of connotation with condensation.

What does it look like?

Mould growth will appear on any damp surfaces such as plaster, wallpaper and timber and is associated with condensation problems in many buildings. It can be identified by its appearance (unsightly growths of various colours — greens, yellows, pinks, black, grey or white), odour (musty and damp), and fears of health and hygiene considerations (particularly in food processing industries).

There are three principal features common to the broad range of mould fungi:

  1. Simple food requirements: able to exist on non-nutrient materials such as plaster and brick which have traces of contaminating organic matter.
  2. Produce vast number of spores which allow rapid adaptation to particular environments.
  3. Grow The very quickly under suitable conditions.

The main requirement for the development and growth is a source of moisture although food, oxygen and a suitable temperature are also important. It is available water which is critical to mould development and different materials at the same moisture content often have different water availability.

The appearance of mould growth in buildings often suggests poor standards of property maintenance and/or domestic activities encouraging condensation. Prolonged exposure to mould growth will cause disintegration and disruption of certain painted surfaces. Paper and certain fibre building fabrics may also be softened and deteriorate as some mould species are capable of digesting cellulose.

The Cost of Unchecked Condensation

Respiratory and Allergic Health Effects of Dampness, Mould, and Dampness‑Related Agents: A Review of the Epidemiologic Evidence Mendell et al (2011).

The evidence produced from the above paper proposed that there were positive associations between dampness and mould with multiple allergic and respiratory effects. It was suggested that prevention methods and remediation could reduce health risks.

What you can do to resolve your Mould infestation

The use of the Damp-Proofing.com anti condensation unit is by far the most cost effective method of eliminating condensation.

Not only is this option the most cost effective option is the best option overall when combined with health risk and property cost.

The average home to redecorate or resolve due to mould can be a minimum of 250 per year this is without taking into consideration the replacement of items such as home furniture and clothes. This can produce stress for the owner or for the tenant; in tenancy circumstances court and compensation events may arise.

The direct cost of a condensation and mould growth problem where only one room has to have mould cleaning or redecorating is at least 250 per year, and in many cases is much more than this, If for example more than one room is involved. Sometimes window frames need to be repainted and repaired, or even replaced. The occupants clothes and other belongings may go mouldy and need to be replaced. In extreme cases the occupant may take a Landlord to the Courts and compensation payments of several thousand pounds may result.

In addition these direct costs; there is a substantial hidden cost which relates to administration. Examples of hidden costs include:

  • Payment of surveyors in subject to tenant cases.
  • Liaising with local authorities (increasing in work holidays and loss of earnings).
  • Legal fees.

Condensation is an increasingly serious problem in dwelling houses and offices. It affects over 50% of Buildings in the UK.

How we can help you

We at Damp-Proofing.com have supplied and installed Input Ventilation Anti-Condensation Units (IVAUs) for an ever increasing number of Local Authorities and Housing Associations for many years.

Our professionalism and expertise means that we pride ourselves on being the best option to resolve your mould issues.

How our IVAUs work

1. The loft space which contains warmer air mixing with air drawn in through eaves.

2. The warmer fresh air is then drawn into the unit where it passes through a special air filter.

3. The filtered air is introduced into the property through the diffuser grille, located centrally at ceiling level in the landing of the property, and is circulated around the property.

4. The fresh air then mixes with the warm air in the property, thus combating the condensation.

5-7. The stagnant air is then expelled through natural leakage points in the property. This also serves to help prevent cold draughts entering the property.

Energy conservation is the responsibility of all of us.

Conventional extractor fans potentially waste over a million kilowatts of energy every year — which is comparable to the total output of two large power stations! Replacing conventional extractor fans with heat recovery systems would save at least half of that energy loss.

Input ventilation anti condensation units is a successful and cost-effective way to cure condensation. Input ventilation with heat recovery offers you even more benefit because it can save over 80% of heat which would otherwise be wasted by transferring it to the incoming fresh air supply.

Running Costs only 1p-9p A Day.

We can Supply the Unit only. Please telephone us for a Quotation.

For a survey please call the office on:

Condensation

It is a well known fact that some houses and flats suffer from condensation. Walls, ceilings, and sometimes floors become damp and discoloured, and unpleasant smells arise as a result of mould growing on the surfaces.

Why Condensation Occurs

Condensation occurs when warm moist air meets a cold surface. The risk of condensation therefore depends upon how moist the air is and how cold the surfaces of rooms are. Both of these depend to some extent on how a building is used.

When Condensation Occurs

Condensation occurs usually in winter because the building structure is cold and because windows are opened less and moist air cannot escape.

Where Condensation Occurs

Condensation which you can see occurs often for short periods in bathrooms and kitchens because of the steamy atmosphere and quite frequently for long periods in unheated bedrooms, also sometimes in cupboards or corners of the rooms where ventilation and movement of air are restricted. Besides condensation on visible surfaces, damage can occur to materials, which are out of sight, for example from condensation in roofs.

Three things are particularly important.

1) To prevent moist air spreading to other rooms from kitchens and bathrooms or from where clothes may be put to dry.

2) To provide some ventilation to all rooms so that moist air can escape.

3) To use heat reasonably.

The following notes give advice on how you can help to prevent serious condensation in your home.

Remove Moisture Content of Room Air

Good ventilation of kitchens when washing or drying clothes or cooking is essential.

If there is an electric extractor fan, it should be used when cooking or drying clothes and particularly whenever the windows show any sign of misting. Leave the fan on until the misting has cleared.

If there is not an extractor fan, open kitchen windows but keep doors closed as much as possible.

After bathing keep the bathroom window open and shut the door for long enough to dry off the room.

Condensation

In other rooms, provide some ventilation. In old houses, a lot of ventilation occurs through fireplace flues and draughty windows. In modern flats and houses, sufficient ventilation does not occur unless a window or ventilator is open for a reasonable time each day and for nearly all the time the room is in use. Too much ventilation in cold weather is uncomfortable and wastes heat. All that is needed is a very slightly opened window. Where there is a choice open the upper part such as the top hung window. About a 10mm opening will be sufficient.

Avoid the use of portable paraffin or flue-less gas heaters as far as possible. Each litre of oil or gas used produces the equivalent of about a litre of liquid water in the form of water vapour. If these heaters must be used, make sure the room they are in is well ventilated.

If condensation occurs in a room which has a heating appliance with a flue the heating installation should be checked as the condensation may have appeared because the appliance has become blocked.

Do not use unventilated airing cupboards for clothes drying.

If washing is put to dry, for example in a bathroom or kitchen, open a window or turn on the extractor fan enough to ventilate the room. Do not leave the door open or moist air will spread to other rooms where it may cause trouble.

Provide Reasonable Heating

Try to make sure all rooms are at least partially heated. Condensation most often occurs in unheated bathrooms.

To prevent condensation the heat has to keep room surfaces reasonably warm. It takes a long time for a cold building structure to warm up so it is better to have a small amount of heat for a long period rather than a lot of heat for a short period.

Houses and flats left unoccupied and unheated during the day get very cold. Whenever possible, it is best to keep heating on, even at low level.

In houses, the rooms above a heated living room benefit to some extent from heat rising through the floor. In bungalows and in most flats this does not happen. Some rooms are especially cold because they have a lot of outside walls or lose heat through a roof as well as walls. Such rooms are most likely to have condensation and some heating is therefore necessary. Even in a well-insulated house and with reasonable ventilation it is likely to be necessary during cold weather to maintain all rooms at not less than 10c in order to avoid condensation. When living rooms are in use temperature should be raised to about 20c.

Any sign of mould growth is an indication of the presence of moisture and if caused by condensation gives warning that heating, structural insulation or ventilation, or all three may require improvement.

New buildings often take a long time before they are fully dried out. While this is happening they need extra heat and ventilation. At least during the first winter of use many houses and flats require more heat than they will need in subsequent winters. Allowance should be made for this. It is important that wet construction should be free to dry out. In some forms of construction, especially flat roofs of concrete, final drying may only be able to take place inwards. Ceiling finishes, which would prevent such drying out, should not be added unless advice has been given that this would not matter.

Effect of Increased Ventilation on Fuel Burning Appliances.

If an occupier proposes to fix an extractor fan or otherwise change the ventilation in the room containing a gas or solid fuel appliance, he should obtain advice from the installer of the appliance about the risks from t

Painting faults

Particularly noticeable in shiny, gloss surfaces, these are caused by specks of dust which may have been on the surface, on the brush or in the paint itself. Or a very fine skin on the surface of the paint (especially non-drip gloss) may have got broken and worked into the paint on application.

Make sure the surface is clean and free of dust at each stage of the work: after burning off or rubbing down, and before applying primer, undercoat and top coat. Clean the surface with a tacky (resin-impregnated) rag or a clean, lint-free one dampened with white spirit. Pay particular attention to corners since pockets of dust here, though difficult to clean with a rag, will be picked up on the brush and spread across the surface. Use a pointed stick under the rag to ensure every particle of dust is removed from the corners. Paint brushes must be cleaned and even new brushes need rinsing before use as the bristles will contain some dust and loose hairs. Wipe the lid and rim of the paint can before removing the lid otherwise any dust will fall into the tin. It is a good idea to transfer a small amount of before paint into a clean paint kettle or other container and work from this. If dust falls into the kettle only a small amount of paint will be affected. Clean the room thoroughly before starting work and allow time for dust to settle using paint.

Dont try to remove specks while the paint is still wet as you will only add to the problem by smearing the paint. Allow the paint to harden for several days; even though it may seem dry after a few hours, only the surface will have dried. Rub down the affected areas with fine wet and dry glasspaper, wash with clean water, dry thoroughly and apply a new finishing coat. Skin often forms on old paint. If you spot it, carefully lift it away before stirring; if it is extremely thin you can stir it into the paint and then strain the paint through fine muslin or mesh.

Paint falling away from surface is due to poor preparation or bad use of primer. It can take weeks to show and will usually be confined to small areas on the surface.

Clean and prepare the surface thoroughly. If stripping back to bare wood apply a suitable primer. Emulsion flaking from walls or ceilings normally means you have applied the paint over distemper. Before painting, remove distemper by washing and scraping off the loose material, covering the remainder with a coat of primer sealer.

If flaking occurs in small patches, strip these areas back to the bare surface, fill depressions with fine surface filler and repaint. If flaking is extensive, however, you will have to strip off the whole lot and start again.

Slow drying

Sometimes paint (particularly oil-based paint) will take a few weeks to dry or even remain permanently tacky. This indicates you applied the paint over a dirty or greasy surface, used an unsuitable thinner or did not stir the paint before applying.

Clean and prepare your surface thoroughly paying particular attention to skirtings which tend to collect a build-up of polish from the floor. Always stir the paint. You can add a small amount of proprietary dryer to stocks of old paint but never to new paint, which should be returned to the manufacturer for testing.

If the room is badly ventilated, open the windows for a few days to see if this accelerates drying. If not you will have to strip off all the paint with thinners and start again or refer to the manufacturer for advice.

Mostly affecting exterior woodwork, blisters can vary in size from pin heads to large areas. The cause is moisture in the wood or on the surface, trapped between coats of paint, or there may be resinous knots in the wood. Another less common cause is painting over a soft, thick coat. The action of very strong sunshine when any of these conditions exist is likely to cause blistering.

Try to paint external woodwork towards the end of the summer when, ideally, it should have dried out completely. If this is not possible, try to paint in dry, warm conditions. Dont paint immediately after rainfall or washing down, unless the surfaces are thoroughly dried off. Strip off any thick, soft paint and always apply knotting to all resinous areas after stripping back to bare wood.

Cut off the surface of the blister and with fine wet and dry glasspaper rub back to a sound surface or bare wood if blistering is extensive. Apply knotting and primer as necessary, fill depressions with fine surface filler and apply undercoat and top coat.

Runs, sags and wrinkles

Fine lines or drips on a painted surface result from bad application. Wrinkles are likely to occur on thick, sagging paint.

Do not overload the brush and always brush out each application before adding another. Look at the paint five minutes after application; it may still be possible to brush out any runs.

If you notice runs before the paint has started to dry, brush them out lightly; if paint is drying, you will smear the surface. Or treat as for Pimples.

Dull gloss

Dull finish occurs if thinners used wrongly, surface not properly primed or undercoated. undercoat not given time to dry or finish over brushed or painted in damp or frosty conditions.

Prepare thoroughly. Leave the undercoat to dry for the recommended time, avoid using a thinner in gloss paint and do not apply in damp or frosty weather conditions.

Allow the paint to dry, then rub down lightly with fine glasspaper, dust off and apply a new finishing coat.

The colour of the previous coat shows through the dry paint film indicating another coat is needed. Grinning may also occur if you use the wrong undercoat, do not stir paint sufficiently, thin it too much or overbrush finishing coat.

Use the correct undercoat and the recommended number of finishing coats. Make sure you stir the paint according to the manufacturers instructions. Never brush out the finishing coat too far.

Apply extra finishing coats as needed.

Brush marks

These can be seen in the finished paint. The cause is insufficient rubbing down of the old paint surface, faulty application (applying the paint too thickly and not brushing out correctly) or using poor quality brushes.

Carefully prepare the surface, making sure poor paint is rubbed right back. Apply the paint evenly and finish brushing out in the direction of the grain. Slightly thin excessively thick paint and always use good quality brushes.

Painting faults

Particularly noticeable in shiny, gloss surfaces, these are caused by specks of dust which may have been on the surface, on the brush or in the paint itself. Or a very fine skin on the surface of the paint (especially non-drip gloss) may have got broken and worked into the paint on application.

Make sure the surface is clean and free of dust at each stage of the work: after burning off or rubbing down, and before applying primer, undercoat and top coat. Clean the surface with a tacky (resin-impregnated) rag or a clean, lint-free one dampened with white spirit. Pay particular attention to corners since pockets of dust here, though difficult to clean with a rag, will be picked up on the brush and spread across the surface. Use a pointed stick under the rag to ensure every particle of dust is removed from the corners. Paint brushes must be cleaned and even new brushes need rinsing before use as the bristles will contain some dust and loose hairs. Wipe the lid and rim of the paint can before removing the lid otherwise any dust will fall into the tin. It is a good idea to transfer a small amount of before paint into a clean paint kettle or other container and work from this. If dust falls into the kettle only a small amount of paint will be affected. Clean the room thoroughly before starting work and allow time for dust to settle using paint.

Dont try to remove specks while the paint is still wet as you will only add to the problem by smearing the paint. Allow the paint to harden for several days; even though it may seem dry after a few hours, only the surface will have dried. Rub down the affected areas with fine wet and dry glasspaper, wash with clean water, dry thoroughly and apply a new finishing coat. Skin often forms on old paint. If you spot it, carefully lift it away before stirring; if it is extremely thin you can stir it into the paint and then strain the paint through fine muslin or mesh.

Paint falling away from surface is due to poor preparation or bad use of primer. It can take weeks to show and will usually be confined to small areas on the surface.

Clean and prepare the surface thoroughly. If stripping back to bare wood apply a suitable primer. Emulsion flaking from walls or ceilings normally means you have applied the paint over distemper. Before painting, remove distemper by washing and scraping off the loose material, covering the remainder with a coat of primer sealer.

If flaking occurs in small patches, strip these areas back to the bare surface, fill depressions with fine surface filler and repaint. If flaking is extensive, however, you will have to strip off the whole lot and start again.

Slow drying

Sometimes paint (particularly oil-based paint) will take a few weeks to dry or even remain permanently tacky. This indicates you applied the paint over a dirty or greasy surface, used an unsuitable thinner or did not stir the paint before applying.

Clean and prepare your surface thoroughly paying particular attention to skirtings which tend to collect a build-up of polish from the floor. Always stir the paint. You can add a small amount of proprietary dryer to stocks of old paint but never to new paint, which should be returned to the manufacturer for testing.

If the room is badly ventilated, open the windows for a few days to see if this accelerates drying. If not you will have to strip off all the paint with thinners and start again or refer to the manufacturer for advice.

Mostly affecting exterior woodwork, blisters can vary in size from pin heads to large areas. The cause is moisture in the wood or on the surface, trapped between coats of paint, or there may be resinous knots in the wood. Another less common cause is painting over a soft, thick coat. The action of very strong sunshine when any of these conditions exist is likely to cause blistering.

Try to paint external woodwork towards the end of the summer when, ideally, it should have dried out completely. If this is not possible, try to paint in dry, warm conditions. Dont paint immediately after rainfall or washing down, unless the surfaces are thoroughly dried off. Strip off any thick, soft paint and always apply knotting to all resinous areas after stripping back to bare wood.

Cut off the surface of the blister and with fine wet and dry glasspaper rub back to a sound surface or bare wood if blistering is extensive. Apply knotting and primer as necessary, fill depressions with fine surface filler and apply undercoat and top coat.

Runs, sags and wrinkles

Fine lines or drips on a painted surface result from bad application. Wrinkles are likely to occur on thick, sagging paint.

Do not overload the brush and always brush out each application before adding another. Look at the paint five minutes after application; it may still be possible to brush out any runs.

If you notice runs before the paint has started to dry, brush them out lightly; if paint is drying, you will smear the surface. Or treat as for Pimples.

Dull gloss

Dull finish occurs if thinners used wrongly, surface not properly primed or undercoated. undercoat not given time to dry or finish over brushed or painted in damp or frosty conditions.

Prepare thoroughly. Leave the undercoat to dry for the recommended time, avoid using a thinner in gloss paint and do not apply in damp or frosty weather conditions.

Allow the paint to dry, then rub down lightly with fine glasspaper, dust off and apply a new finishing coat.

The colour of the previous coat shows through the dry paint film indicating another coat is needed. Grinning may also occur if you use the wrong undercoat, do not stir paint sufficiently, thin it too much or overbrush finishing coat.

Use the correct undercoat and the recommended number of finishing coats. Make sure you stir the paint according to the manufacturers instructions. Never brush out the finishing coat too far.

Apply extra finishing coats as needed.

Brush marks

These can be seen in the finished paint. The cause is insufficient rubbing down of the old paint surface, faulty application (applying the paint too thickly and not brushing out correctly) or using poor quality brushes.

Carefully prepare the surface, making sure poor paint is rubbed right back. Apply the paint evenly and finish brushing out in the direction of the grain. Slightly thin excessively thick paint and always use good quality brushes.


Leave a Reply