Is Artex really that dangerous? Know the facts and not just urban myths. Guns are not dangerous - it's the persons holding it that is. Artex - how to live with it safely. This blog provides practical information about the risks involved and who is most at risk.

Employing a contractor can end up being a nightmare. This blog highlights a lady who chose a 5 star Central Heating contractor as recommended by one of those Internet 'Trader Checking' businesses. Read what happened and what she ended up with.

Hot always goes to cold unless energy is used. It cannot be stopped, only slowed down. So those companies who claim they can stop heat loss are kidding you. Heat is normally the product of molecule collisions. Similar to your hands becoming warmer if you quickly clap them together for a short period. In solid items the molecules cannot move much other than vibrate therefore requires a lot of energy to keep the vibrations going. That is why it takes a lot of energy to heat dense materials such as metal, masonry and glass. (Technically glass is a super cooled liquid as opposed to a solid).

We’re following on with Tracy and Roger and their apartment being expensive to heat. As their apartment has very high humidity levels the cost of heating will be higher than it need be. To heat anything be it a brick, a saucepan, a kettle full of water, they all require energy. However the amount differs with each material or liquid. Water for instance requires a lot of energy to heat it but it also holds heat reasonably well. If the weather is very hot and humid our body sweats to try and keep us cooler. The idea is the sweat being water will absorb heat energy and cool the surface of the skin. Conversely if we are feeling cold our body stops producing water vapour and raises the fine hairs that cover the body in order to trap air from moving. Still air is a good insulator. The bottom line is water and wet things take a lot of energy to try and raise the temperature. Dry air takes far less energy to heat it. Tracy and Roger have, or rather had a very humid apartment that made everything damp. Even the air was full of water vapour so it took a lot of energy to raise the air temperature. Drying the whole apartment out with the dehumidifier mentioned in the previous blog has made the air will be easier to heat. The air is in contact with most things in the apartment so it will raise the temperature of everything it is in contact with until it is all at the same temperature.

Mostly breathing and as a result of bathing. Moisture from breathing is easy to prove but it might be a surprise just how much water one adult produces. If the air is cold you can see breath condensing in the air. But we also breathe through our skin. More accurately we expel water vapour through the millions of holes in the skin. The vapour condenses (sweat) and the water then absorbs heat cooling us down. When we sleep our body temperature needs to cool down by about 1 or 2 degrees. To cool down whilst feeling cosy in bed means expelling water vapour – sweat. It mostly soaks into our PJs and into the bed linen, covers and mattress.

The Blog this week is about: Myths and mis-information regarding Condensation & Moulds There are Company websites proclaiming they are ‘experts in condensation and mould issues’. They state things like: ‘Get the professionals in’, ‘The condensation experts’. But should you believe them? How do you know if they are just a website that states ‘pseudo facts’ that are nothing more than just myths? Even Local Councils and Housing Associations get taken in. Look at some of their facts and compare with actual proven science: Opening windows ‘Open the window and let all the steam out’ – It helps very slightly however doesn’t do much at all to reduce the condensation around the home. As mentioned in a previous blog dry air is molecules of nitrogen (78%), oxygen (21%) and trace gases (1%) with space in between them. Humid air is dry air with water molecules (vapour) in the spaces. Water can be solid as ice, liquid as water or gas as vapour. The molecules are exactly the same with a ratio of 1 hydrogen atom to 2 oxygen atoms (H2O). Water can vaporise at temperatures well below boiling point (100°C). The evidence is water evaporates from the oceans and seas etc. Leave a glass of water and eventually the water will evaporate. (If you want to find out more it will be in Construction Science Explained – www.buildabooks.co.uk out next year). The atoms of a water molecule remain the same whether it is water, ice or vapour. As vapour they can float in the spaces between the other gases in the air. That process is termed humidity. A common ‘myth-statement’ ‘Steam is water vapour’ . Not true. Steam is water. It is water vapour that has condensed in the air therefore it is actually condensation and visible. Gases including water vapour are not visible. Molecules are more than one atom. It can be the same type or different types termed compounds. Either way although they do not have a weight as such (Atoms have an atomic weight that is a comparison with a carbon atom). Atoms do have a mass though. That mass can be attracted by a greater mass. The greater the mass the stronger the attraction. (Similar to weight). The planet Earth is made up of an enormous number of atoms. The combined attraction (pulling force) we call ‘gravity’. It’s a bit like a very large magnet will attract a smaller item such as a nail. The nail if magnetised will attract a smaller pin, and so it goes on down the sizes. Gravity however is a strong attractive force that can go through most things and still attract. It can go through the tallest buildings and still have an effect on an aircraft flying at 35,000 feet in the air. So logically it also has an attractive force on every atom be it in a solid (the aircraft), a liquid (rain comes downwards) and the gases. If it didn’t have any effect on the gases they would all have gone off into outer space. Irrefutable evidence: the higher the altitude the less molecules. We state that the air is ‘thinner’. What it actually means there are less molecules, less nitrogen, less oxygen etc. and a lot more space. So what has all this proved? Air can be dry – no water vapour in it. Very rare though, most air has some water vapour in it even in the hottest deserts. Atoms have a mass. The more mass in the same volume means there is more atoms for gravity to act on. We term that ‘weight’. If you could take say a gold bar that has a weight on Earth of 6kg then send it to the Moon it would then only weigh about 1kg. The gold bar hasn’t changed, it still has exactly the same number of atoms in it. The only difference is the attraction force ‘gravity’. The Moon is that much smaller so less atoms to to do the attraction. If air is heated the molecules will become more energised. They will move more quickly and collide with each other. The collisions tend to end up as the molecules bouncing off and going in a different direction to their next collision. All the time that is happening gravity is trying to pull them down to the lowest point and slows them down The result is less collisions = less heat generated = the air cools down. If a cubic metre of air is considered there will be a given number of air molecules in it at a specific temperature. If the molecules are given more heat (energy) they become more energised and travel faster and further. There will be fewer molecules in the cubic metre as the temperature rises. Fewer molecules means the pull of gravity has less effect. The cooler air will push the warmer less dense air upwards. Warm air rises and that is the reason why. Evidence: the attractive force of gravity can be compared to magnetic attractive force. The closer together metal particles are the easier the magnet can attract them (ignore friction). Warm air is less dense than cooler air as there are fewer molecules for gravity to act on. Warm air therefore is displaced by cooler air that has more molecules in the given volume. The end result is warmer air will be pushed upwards by the cooler air trying to get as low as possible. That was considering dry air only; Nitrogen, oxygen and trace gases argon and carbon dioxide. Now add water vapour. Water vapour (H2O) has mass so will be attracted by gravity. The more vapour that can fill the gaps in the dry air the denser the molecules. The more effect by gravitational pull and the air is effectively ‘heavier’. At the same temperature the humid air is going to sink. As is sinks it displaces (pushes) the drier air out of the way. If there are walls then the only place the lighter drier air can go is upwards. It is said it ‘rises’ but it is actually it is being pushed upwards by the more dense air. (Nothing can go upwards without energy being used, not even atoms). So dry air is less dense than humid air at the same temperature. The warmer the air the fewer number of molecules therefore they get pushed upwards (rise).

The Blog this weeks is about: Condensation & Moulds Now is the time that condensation and mould growth are most noticeable. The temperatures outside are dropping and rain and damp mornings are commonplace. Here are: · 6 easy ways to reduce Condensation and moulds around your home And if you’re interested into the ‘whys and what ifs’ then the science will explain all. The science behind as to: · ‘Why does mould grow behind and under my furniture?’ · ‘Why have my best leather boots gone mouldy in a box under my bed?’ · ‘What if I turn the heating up?’ · ‘Why do my clothes get mould on them when they’re in a drawer?’ · ‘Why does the grout on my bathroom tiles go mouldy?’ To start with though: 6 easy ways to reduce Condensation and moulds 1.  Install an efficient extractor in the bathroom over the shower area. 2.  Turn the extractor on before you turn the shower or bath taps on. 3.  Ensure there is a minimum gap of 10mm (3/8”) under the bathroom door. Make sure the gap is above the top of the carpet pile. 4.  Have the maximum over-run (30mins) set on the timer. Or leave the extractor on for 30minutes after you have finished the shower. 5.  Wipe down the shower walls and shower tray or bath to remove as much water as you can. 6.  Keep the bathroom / en-suite door closed or very slightly open to keep the humid air in that room. Stop it spreading throughout your home. Those 6 easy steps will significantly reduce condensation in your home. Mould needs moisture to multiply and you’ve just reduced that. The science for those interested: Air is mainly nitrogen (78%) and oxygen (21%), plus 1% traces of other gases. That’s only a guide though. Imagine nothing, absolutely nothing. No atoms, no gases, not a single thing – space – nothing. Now imagine lots of tennis balls and table tennis balls in that space. They can represent the nitrogen and oxygen molecules. There is still space between them though where there is nothing. In that space there will be argon and carbon dioxide. They make up about 1% of the gas content of air. Now we can put in some other gases into the spaces: Hydrogen and some more oxygen at the ratio of H2O or more commonly known as water. Water can be as a solid (ice), liquid (water) or gas (vapour). It is still H2O though. Gravity acts on gases in the same way as it does on solids and liquids. The main difference is that the molecules in gases have energy that makes them continually move. They continually collide with other molecules bouncing around in the space. When there are lots of molecules close together (more dense) the gravity has more effect. Dry air has fewer molecules than humid air therefore lighter (at a comparable temperature). Back to the shower – Hot water has put more energy into the molecules. They are moving around very quickly colliding frequently. Eventually unless more energy (heat in this case) is put in the molecules they will slow down and collide less. The pressure will slowly decrease and more molecules will be in one place (density = mass divided by volume). The humid air will cool down and become even heavier as more molecules gather together. End result; A hot shower will produce a lot of water vapour (it hasn’t got to be above 100°C though) The water vapour will go in between the nitrogen and the oxygen molecules until it virtually fills all the spaces. That is saturation point. If the air is at a specific temperature it can be calculated how much water vapour it can take up. As the air cools down the molecules slow down and the collisions reduce. The number of molecules in the same volume increases and the air becomes denser. Cooler saturated air is heavier than warmer drier air. Therefore the humid air will go to as low as it can get – the floor. Leave the bathroom door open wide and all that humid air will fall out of the room into other rooms, even down the stairs. As it does so the humid air will condense on anything that is cooler than the air. Cold surfaces like walls, windows, ceramic tiles, and carpets. Furniture such as beds, settees, wardrobes and drawers will all be cooler than the humid air so will condense the moisture. Areas behind furniture are particularly vulnerable as there will be minimal heat (thermal convection). The gap will have a cool wall on one side and cool back of the furniture on the other. The wall is likely to have plaster on it, or be made from a sheet of plasterboard. Gypsum plaster requires a lot of water to enable it to be fully workable. Literally hundreds of litres are required to plaster out a house. It then takes about a year for it to fully evaporate off if the room air is dry. The plaster when dry is then full of minute holes that the water once filled. Crystals have formed with tiny gaps between them. The result is a hygroscopic material, meaning it will absorb moisture where available. Now back to the plot. Shower of hot water vapour saturating the air. The hot water is providing energy to the air molecules and they are all moving very fast and colliding. Gravity is trying to pull all the molecules downward therefore slowing them down. As they slow down more molecules gather in a specific volume of air and it sinks downwards. Humid air contains more molecules than dry air therefore it is heavier and will sink. Any material that is cooler than the humid air will condense the water vapour back into liquid form – water. If it is a non-porous material such as glass, metal or plastic it will form beads of water – condensation. If it is a porous material such as a carpet, bed linen, curtains, clothes then the condensation will soak into the material and it becomes damp. Hygroscopic materials actually pull the moisture into them (a bit like kitchen towel soaks up spills). The walls and ceilings are plaster and most likely gypsum plaster and will pull in water vapour. Even if the surface has been painted over with a plastic emulsion the vapour can still go though. Water molecules are too big though so they cannot pass through. So what have we ended up with? Hot and steamy air in the shower room. The air is cooling down and the high humidity air drops to the floor. The door is left open and all that humid air has a greater pressure than the cooler air of the other rooms. The pressure enables the humid air to roll across the floor and down stairs if there are any (not very common in a bungalow though) filling anywhere it can. As it does so the water vapour condenses out of the air and either forms condensation (water) or makes things damp. Enter the mould spore. Air isn’t just nitrogen and oxygen plus a few trace gases. It also contains pollutants. They can be particulates (tiny particles of solid matter that are so small they cannot normally be seen). They are there though. That is what dust is. There is enough energy in air to bounce the gas molecules against the solids causing them to float. As the air cools down, less energy and the solid particulates are pulled downwards by gravity. (Dust settles more so at night when it is cooler and the air more static). Moulds Mould spores are microscopic, so tiny they are virtually invisible. They are naturally blowing around in the air. Natural and necessary they are one of nature’s cleaners taking anything they can back into the ground. A dead tree would still be there forever if it wasn’t for moulds and fungi. The spores float in and out of everywhere including buildings and vehicles. We breathe them in and our bodies have various methods to stop them doing any damage to us. If we have a breathing issue though, or generally unwell the spores can set up reactions. They can cause eyes and ears to itch, throats to become inflamed, breathing difficulties and possibly worse. Black spore mould is very common. The spores are present in the air as mentioned. If they become attached to a host surface they can soak up moisture and the chemicals it contains. They cannot eat as such but absorb moisture. If the moisture has carbon in it that is food to the spore and it will multiply. More moisture, more carbon = more spores until there is a colony of them. Sugar is made up of carbon. Cellulose is the natural sugar found in wood and wood based products such as paper and cardboard. It is also a base for wallpaper paste hence; ‘Poly cell ’. Plaster is hygroscopic and will soak up moisture from the air. The wall is a conductor of heat energy therefore the plaster will be continually cooled down. The plaster will condense water vapour and any wall paper will in turn become damp. The mould spores can suck up (actually they can’t ‘suck’ they just absorb) the moisture including the carbon content in the cellulose. The wallpaper is a wood pulp product and the paste also full of cellulose. Mould spores can then multiply very quickly. More steamy showers = more moisture everywhere = mould growth. The cooler areas behind curtains, behind furniture, in and under drawers, under mattresses and in wardrobes are all ideal for mould spores. The moist air will go everywhere.