Condensation is the main cause of black mould. More than half the homes in the UK suffer some condensation problems.
Usually the mould grows on the coldest corners in the home.

Most affected are outside corners, up a corner and the corner of ceilings. In high humidity mould can grow anywhere. Visit Condensation solutions

Damp living conditions are usually associated with poor ventilation and Condensation. Damp conditions are perfect to breed dust mites. 80% of people who are asthmatic are affected by house dust mites
Penetrating damp and rising damp are associated with older property. Please visit the diagnosis page.

This is associated with condensation which encourages smell-emitting moulds. Lack of ventilation, low level heating and poor insulation contribute to mustiness.

Homes with sub floors straight on to soil may suffer musty smells – this can be solved by covering the sub floor which is very expensive. Positive ventilation will reduce the problem by expelling the smells.

This is a classic condensation symptom. Cold damp places are s perfect for moulds and fungi to thrive. There is no other reason for this symptom other than condensation.

The wardrobe shown was new 2 months ago and was not even touching the cold wall.

Move furniture away from cold outside walls where possible and then visit Condensation solutions

Condensation is allowing mould to grow on the cold surface - the mould is eating the leather.
Condensation causes £1000’s worth of damage to clothes, furniture, books, shoes and decorations.

There is a condensation problem early in the morning. Beads of moisture form at about 4am in the morning when the wall is really cold and evaporate later in the day. By the time you measure the damp with a meter the wall is dry.

The photo shows a typical pattern: the wall is coldest in the corner. The shape of the black mould mirrors the temperature of the wall surface.

This is when a moisture meter is really useful!

This is definitely condensation there is no other cause! water droplets forming on the cold surface.

On wallpaper and clothes the water soaks in but it's still there

On polished leather the damp tends to stay on the surface which is why the mould attacks so quickly

..... visit Condensation solutions

The "dryhomes roof vent" can be slipped between the joints of the sarking felt to open up enough of a gap to vent the roof.
Fresh dry air from outside enters via spaces between the slates or tiles.

IMPROVE VENTILATION

Traditionally sofit vents are installed and where this is not feasible tile vents added. This is very expensive and time consuming ......so you may be able to use Dryhomes Roof Vents. Check your sarking felt (the material under the slates) has overlapping gaps.

BENEFITS

• Very cheap and effective
• Only 1 "dryhomes vent" is needed per 5mtrs of floor space.
• Quick to install - the average roof would take 1 hour
• No scaffolding - installation is achieved from inside the roof
• Can be DIY fitted with no tools

Don't Install a positive pressure system in a damp loft - it won't work

Dampness, dripping, glistening of water droplets and musty smells means you have a poorly vented roof.
This is well below modern British Standard.

Damp roof voids are prone to rot and insect attack.

Dry rot is unlikely because condensation only occurs under humid conditions and dry rot needs a constant supply  of water.

Mould growth on goods stored in the roof is a sure sign of a condensation problem.

Without management this will become a bigger problem, damp insulation will not be effective and heating bills will rise.

Don't Install a positive pressure system in a damp loft - it won't work

CHECK LIST

• Leaking fan vents (ducting with gaps letting damp air into the roof) should be replaced immediately.
• Turn off light in roof and see how much daylight you can see. If none - you have a 'tight roof' which needs venting.
• Outside look up at the eaves. Are there any sofit vents?
• Have tile vents been fitted amongst the slates on the roof itself?
• Has cladding been added and covered the sofits so the roof cannot breath?
• Is insulation inside covering the vents?
• Are water tanks covered to stop evaporation?

This is most likely due to rising damp. Rising damp can affect internal and external walls rarely rising more than 3 feet - if it does you may have very high humidity as well…..
What is rising damp? Damp that rises up a wall from the soil under the house. If there is no damp proof course the bricks will absorb the water slowly like a sponge and then evaporate into the house.
There were no effective damp courses in houses built before the 1930’s.
Even with a good damp course there may be bridging of the damp course with mortar in the cavity allowing water from the ground to rise up the wall.
The damp course may have been bridged by a new solid floor on the inside.
The existing damp courses can break down and fail. Then a new damp course needs injecting.

The original damp course may have been bridged allowing water to get up the wall. This is particularly a problem in single skin construction. Reduce the ground level.
If the ground level needs to be kept as it is insert a vapour control barrier between the house wall and the raised area.
Have a new damp course injected higher up the wall and the base of the wall ‘tanked’ against penetrating damp. Note that there may be perished plaster inside and without replacing the plaster the wall may fail to dry out.

 Salts are drawn up with water from the ground where your house is built. The water evaporates leaving a salty deposit which shows as dust or crystals.
This is possibly penetrating damp if wall is below ground level.

Damp sittings show the wall is damp. It is most likely caused rising damp. Penetrating damp can also wet the wall. Skirtings can start to rot because of severe condensation but this is rare. PCA survey to establish the cause of the dampness.

Look carefully – has there been re-plastering? Some builders use waterproof render to disguise rising damp. Wainscoting fulfils the same function of hiding problems. Covering up does not solve the problem it merely makes damp rise higher. That is why you can see damp start suddenly high up a wall.

There are many reasons and wrong diagnosis is expensive so ask a PCA remedial treatment company to investigate.

If you live in 15 miles from Torbay Dampco Ltd will be able to help

Ends of joists, or the floor plate, have dropped because they have rotted. Wet rot is usually easily rectified. The area can be rebuilt using treated timber. Vapour control barriers (plastic membranes) must be used to protect the new wood from the damp masonry. Old timbers, not affected, should be treated with fungicide. Make sure there are adequate air bricks and they are all clear - this keeps the floor timbers air dry and prevents rot.

Plaster fungus is very jelly like and spongy. Usually white or creamy. Look for plumbing problems but it can grow on any damp surface – this is not a serious problem but the damp should be identified and stopped. Timbers will be eaten by fungal growth. Check that it is not (the very serious) dry rot – see below.

This is Dry rot and should be tackled immediately as it is invasive and expensive to treat. Call the PCA immediately and get professional advice.
About 80% of cases of true dry rot are caused by faulty plumbing so get a plumber in if there is any local pipe work so he can check for leaks. Plumber Yellow Pages
Dry rot needs a permanent source of water such as damp under the house so investigate this possibility. The water may only be a small drip. For this reason dry rot is rare in roofs because rain is intermittent and the dry rot will die if it becomes dry.

Note: Dry rot is so called because it can transport water, via mycelium, from the source of water to dry timbers. As soon as the timber has been wetted the fungus can start digesting it. Dry rot is the only wood rot that can attack dry timber!

Click on this photo to see how destructive and invasive dry rot can be.

TIP. DIY. Expose the mycelium as soon as possible to assist drying and slow down the invasion – cut water supply to any leaking pipes immediately – rip out loose, rotted timber and fungus and cart away.

There are many reasons and wrong diagnosis is expensive so ask a PCA remedial treatment company to investigate.

If you live within 15 miles from Torbay call Dampco Ltd
straight away. Dry rot should be treated quickly.

Classic condensation. Often when insulation is missing or substandard as this makes the ceiling cold. The pattern of mould may be in patches where there are no joists as in the photo. Note that the warm joists can be ‘seen’ where there is no mould. Upgrade the insulation and control the humidity.
The old couple, who lived with this for 10 years, had been ‘sold’ new gutters but there was no problem with penetrating damp.

Leaking plumbing – check for bathroom and radiators on the floor above. Most common leaks are shower trays then bath seals against the walls. WC foul pipes can break inside walls. Small drips may cause big problems. If there is a flat above the kitchen could be leaking – washing machine pipes often leak.
This is a common cause of dry rot outbreaks. Plumber or tiler Yellow Pages.
TIP – the same is true downstairs at floor level but harder to spot – many people are not aware of leaks until they fall through the rotten kitchen floor! 

Usually the flashings are faulty where the stack meets the slates.
It could also be because no damp course was built in the chimney stack to stop water migrating down into the house.
Penetrating damp can occur if the stack is porous, badly pointed, has cracked or substandard render or is badly painted. Is the stack in a good condition? See photo!  builder / roofer Yellow Pages

In cavity construction this may be damp migrating across wall ties. Externally problems of corroded wall ties are indicated by horizontal cracking which can also cause penetrating damp. Check to see if heights of outside cracks correspond to inside damp – damp may appear lower but not higher up the wall. PCA survey.
It may be condensation on the cold ties as they make a “ cold bridge” to the outside. Condensation also occurs on dry lined walls which have been fixed by blobs of adhesive, known as dabs. If the wall is lined it will be hollow when tapped – try tapping the damp spot to see if it is a solid dab. Note that lined walls often cover defects and penetrating damp may be the problem.

In solid construction rain can migrate through bricks and across stones.
POINTING. Care should be taken to maintain the pointing particularly where it is difficult to do – behind down pipes etc.
RENDERING. Some solid walls are rendered to stop this damp. Beware that very small HORIZONTAL cracks in render are the worst for damp as they can suck in rain as it comes down the wall.
Renders may crack because of drying stress or movement and these cracks can be repaired.
On poor backgrounds, weak renders or badly keyed surfaces the render can be ‘blown’. This means that the bond has broken down and the render is peeling off. Test this by tapping the surface for hollowness. Occasionally there are individual patches of blown render and these must be replaced or monitored.
If you decide to re-render make sure there is a good bond on the substrate, PVA and adhesives should be considered. The dubbing out coat should be weaker than the final coat and without a waterproofer. The final coat should have a waterproofing additive. Make sure the render is carefully cured  by keeping damp for up to 4 weeks to prevent cracking and strengthen the render.
Lime mortars can be considered as they are less prone to cracking but they are expensive. Always use lime on cob construction to allow movement – lime has the advantage of being easily repaired.
 NB Take local advice….these are only general notes.
PAINTING. Where the walls are painted look carefully at the surface for small holes – many tiny pin holes can cause big damp problems.
LININGS. Older homes were lined inside with lathe and plaster inside to disguise the penetrating damp. This will work if the wall has time to dry between rains but lathes can be attacked by wet rot over a long period – tap the wall inside to detect movement or/and listen to plaster falling down the ‘cavity’
 DIY. Painter or builder Yellow Pages

There can be many reasons but don’t rule out a broken water pipe within the wall.
I have found old lead pipes, with beaten ends, leaking since a local "handiman" chopped it off. Most commonly these pipes are near the back of the house and originally fed the WC.

Call in the experts to design a system to waterproof below ground level.
Control the ground water BEFORE starting any conversion. See below.
Note: Note that conversions are only desirable when light, airy and dry – otherwise they will not enhance the value of your home and will not be fit for purpose.
Ventilation is not an optional extra!

Flats are prone to all manner of problems but chiefly condensation and sometimes penetrating damp.
Inadequate ventilation is a primary cause of misery for people living below ground level. The lack of windows, lack of general airflow between the rooms and poor ventilation make unhealthy conditions inevitable.
Humidity controlled fans – sometimes ducted – can assist the ventilation.

After prolonged wet spell, when the land has little chance to dry out and water pressure builds up, the water table is raised,. All land has water underneath and this water reservoir is an underground lake. Heavy rain adds water and the ‘lake’ level rises. The height of the water surface is known as the water table. If the water table rises under the property it can create pressure in a basement and any waterproofing should be designed to withstand such pressure or remove the water. Many basements never have a problem because of the location or the nature of the subsoil but well designed habitable areas below ground level must be built with potential problems in mind. This is why you need a PCA survey