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The truth about thermal insulation

Robert Cooke • 2 January 2019

Why thermally insulate anyway?

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).

Materials that are made up of thin membranes with voids between them have a mixture of solids and gases. Timber is a good example. Softwood has millions of very small tubes termed trachieds. The walls of the trachieds are very thin cellulose. The air trapped inside the tracheid has very few molecules. The ratio of cellulose wall to void is important.

Due to the cellulose walls being very thin the amount of thermal energy required is small. There are not many molecules to move and the vibrations take longer to slow down.

The thermal insulation qualities of timber are very good, especially softwoods. In comparison PVCu the density of European Redwood is about twice that of extruded PVCu. The former being about 510kg/m3 compared with about 240kg/m3.

However it isn’t an easy comparison. The heat transfer through the material is dependent on how much connection there is between the components.

A dense material can transfer heat easily by conduction but if there isn’t much of it and it isn’t continuous then it can be a good insulation. That is why fibre glass loft insulation is a good insulator. The main component is glass which conducts heat easily.

If the glass is formed into fine fibres it would easily fall apart therefore the manufacturers extrude thousands of fibres from one angle and then thousands at right angles forming a mat like layer each time. The layers build up to form the thickness of the insulation.

Air is trapped between the fibres. It cannot move therefore the few molecules in the air will not transfer heat energy very easily, hence making it a very good insulating material. The insulation is sold in compressed rolls making it easier to transport and get through a loft hatch. The rolls must be ‘fluffed’ up just like a duvet on a bed.

The manufacturing process described has the benefit of added strength preventing the roll of insulation falling apart. ‘Earthwool’ is the brand name used by Knauf. The base material is made from recycled glass bottles therefore making use of waste that would otherwise have gone to landfill.

The thermal value is very slightly less than that advertised for similar insulation however the difference is negligible. However the cost difference is noticeable.

The fibres are long therefore create less dust when the material is handled. It is still advisable to wear a dust mask.

The heated air in the room has risen to the ceiling. As it is in contact with the plasterboard the air temperature will raise the plasterboard temperature until they are equal. The process will cool the air as the energy is transferred. The other side of the plasterboard will naturally be cooler therefore a heat flow will continue until the full thickness of the plasterboard is the same temperature as the air in the room. In reality the flow will actually be cooling the air as all of the molecules in the plasterboard use the energy.

Some of the heat will then pass to the glass fibres and they will heat up. So the glass fibres touching the ceiling will be heating up until they are the same temperature as the ceiling plasterboard. The trapped pockets of air will very slowly increase in temperature.

The temperature within the insulation will cool down gradually as less heat energy is available until the top of the insulation will be at the same temperature as the air in the loft (cold).

There is a point within the thickness of the insulation where it has lost much of the heat energy. Beyond that point putting more insulation to make it even thicker is a waste as there is not much heat energy to save. That point has been calculated at about 270mm thick.

Installing loft insulation

There are several good videos on YouTube showing how to insulate a loft. However some of the technical details are missing. For example in a typical loft the ceiling joists will be 100mm deep (4”). The space between each joist can vary depending upon the span of the roof or room below and the size of the other roof members.

Insulation as previously mentioned is supplied in compressed rolls held in a polythene sleeve.


  1. Measure the width between the joists and using a tape measure and a marker pen put a line on the sleeve. Then repeat several times around the sleeve so that when cutting the section will be parallel. You may find the roll has been pre-marked making it easier to cut. If an old carving or bread knife is available it makes cutting the roll much easier. (If you use your normal carving knife it will require sharpening afterwards).
  2. Place the cut section still in its polythene sleeve roughly in the position you will be starting at. Then cut the sleeve and unroll the insulation fluffing it up when unrolled.

That's straightforward but what about all those cables and junction boxes?


Depending upon the age of the property, and more to the point when the cabling was run will make a difference. Also the quality of workmanship and materials used.

Lighting cable should be a minimum of 1mm² cross section of each wire. The old cables were typically insulated in rubber; red for live and black for neutral. There was not an earth wire within the cable. Some electricians ran a bare earth wire to specific fittings. There were different versions of outer insulation from cotton covered rubber and occasionally lead.

More recently the cabling would have PVC insulation around two cables; live red and black neutral. Between them a single wire without any insulation for the earth line. This too is very old and probably out of its useful lifespan.

If either of those types of cable are present contact a qualified and experienced electrician for advice. DO NOT leave it and insulate over it as it is dangerous. Also do not try moving the cables as the old rubber insulation is well past its useful life and will crack to expose the wiring.

Modern cabling has light grey or white outer insulation with blue and a brown insulated inner wires. The earth line is still bare wire running in between the blue and the brown wires.

Enter 'The Problem!' - DIY man (or woman)

Since the 1950’s DIY has become popular. Why pay someone for something you can do yourself?

The easy answer is would you do your own dentistry on you and your family? Why not?

There are several things to consider if it is to be done safely. Cabling should run along the ceiling joists and be clipped ideally near to the top edge. Light fittings were normally pendant type secured to a length of floor board fixed at both ends to the ceiling joists. The lighting cable would run over the board and through a hole and attached to the ceiling rose. Simple, neat and safe.

DIYer or cheapo electrician. Run the cable loose anywhere and everywhere as can be seen in the photo's above. Apart from a trip hazard or becoming caught up with anything put in the loft space it is all to typical.

There are other reasons / excuses:


  1. the 'electrician' doesn't want to be in the loft for very long (in the summer months it can be very hot in the loft - or very cold in the winter).
  2. The loft is full of stored items so it is difficult to work unless the loft is cleared first.
  3. Running the cables the shortest route = cheaper on materials

Does it matter?

When the insulation is between the ceiling joists the cables will then be on top of the first 100mm (4"). Then placing another 170mm (7") or 200mm (8") on top of the cables sandwiching them in is going to prevent the cables naturally cooling.

Another very common issue is recessed spotlights. Very popular halogen or LED spotlights are cut into the ceiling. Halogen light bulbs produce a lot of heat. If in a ceiling of an upper floor the heat can normally dissipate within the void. However where they are installed in the ceiling of the roof void there is a problem with insulation.

If the insulation covers the lamp holder and transformer there will be a heat build up. The heat can be enough to melt the transformer casing leaving the bare wires exposed with a potential of electrocution if touched. Fire is also possible. Glass fibre will not readily burn as glass is non-combustible but it will melt and char. Recessed light fittings should have a protective heat cup over them that enables the insulation to continue over the fitting but leaves enough space to allow the dissipation of heat produced by the light.

LED lights do not produce much heat but should be protected from the insulation with a cup over the fitting.

Bathroom / shower room extractor ducting

There are several different types of ducting but they all have the same function. To enable humid air to be blown out of the building. Insulating the loft will reduce the heat that would be lost via the ceiling therefore any ducting will be even colder after the ceiling has been insulated. There are insulated ducting tubes available relying on the heat from the ventilated room keeping the duct warm enough to prevent condensation.

Ordinary convoluted PVC ducting will very quickly condense the water vapour and form condensation. If the duct leaks damp patches will form on the ceiling. Ideally if possible have the ducting without any insulation below it. The heat from the room will go through the plasterboard and keep the ducting warm. Place the full amount of insulation over the top of the ducting so that it in effect is protected from the cold. Ducting should have a natural fall towards the outlet for the building so that any condensation will trickle out of the building.

Any water storage tanks in the loft should have a close fitting lid and insulated on all sides and over the lid. If the water tank is supported over the ceiling joists there should not be any insulation below. It used to be said that not having insulation below the tank stopped the water from freezing. In reality the insulation around and on top of the tank should do that. Cold water storage that is on a high level platform is more susceptible to freezing therefore it should be very well insulated. There are kits available that include bags of insulation material and straps so it can be removed for maintenance. Ideally look for water tank insulation that meets 'Water Bye-Laws'.

Water pipes should have pipe insulation around them. There are different types and materials including foamed plastics, hemp bandage, and bubble wrap with a foil layer.

The foamed plastic insulation tubes are very easy to use if the pipe clips are long enough. The insulation tubes are available in 15mm and 22mm diameter meaning that is the size pipe they fit. There are other sizes available but normally used on commercial systems. There are are also different grades that claim better insulation qualities. Are they worth paying a premium price for?

The water pipes in the loft are likely to be from the water storage tanks down to the hot water cylinder (cold feed), cold feed to the shower and bath, could be to the basin depending how the plumber ran the pipes. Those pipes will be full of water all of the time so need to be well insulated. There will be a pipe that takes the water to the tanks. It is part of the mains pipe so it will be under mains pressure and always full of water. It must be well insulated to stop it freezing.

If there is a smaller water tank in the loft it is probably the 'header' tank for the hot water system. There will be a pipe taking the water to it at mains pressure so it must be insulated. There will be another pipe that looks like a shepherds crook. That is a safety pipe from the hot water cylinder. If the boiler controls malfunction and the water temperature goes well over the maximum to boiling point the pressure will push the water up the safety pipe so it falls into the header tank. In normal circumstances the pipe should be empty above the ceiling so nothing to freeze.

Other pipes in the loft may include central heating pipes. Some installers prefer to run the pipes through the loft space to each room rather than taking up the floorboards. Very common where a room has fitted furniture or the modern sheet chipboard floor deck has been used. The pipes in the loft should already be well insulated but it is worth checking.

Pipe insulation is important. In normal winters the roof void / loft is unlikely to become cold enough to freeze water. However in the past the amount of heat entering the loft from the dwelling was enough to keep the temperatures up. Putting the extra layer of insulation will significantly reduce the heat entering the loft so pipes etc. may well freeze. Also there are freak years when the temperatures really fall below freezing and even water mains in the road can burst. So insulating the pipes is a must.

What is more important? The pipe fittings.

A pipe may freeze and burst. Even plastic water pipes can burst. However the fittings such as valves and bends etc. are difficult to insulate. Compression fittings are bulkier than the pipes so foamed pipe insulation will not go round it. That is why some installers use the wrap around hemp bandage and cable ties. The bandage can be wrapped around a valve and then cable tied to keep it in place. The plastic bubble wrap is an alternative but I found that duck tape was the only way to keep in in place.

Service valves such as found on the feed pipe to each water tank should be well insulated but still accessible when needed. The hemp wrap and cable ties works very well.

Why are compression fittings so vulnerable to freezing?

Most commonly made of brass they will conduct heat easily. That means any heat energy in the cold water will be lost through the pipe and even more easily through the fitting. So the area around the fitting will freeze quicker. Moving water freezes at a lower temperature.

Problem

A family goes on a winter holiday for two weeks skiing. They turn the gas off. Why heat the home if they are not going to be there? They arrive back from holiday to find their home completely gutted. Ceilings hanging down, carpets, sofa and everywhere soaked. They go upstairs to find exactly the same thing, everywhere soaked.

The neighbour pops round to say they had heard noises and knew they were away. Probably the ceilings falling down. The emergency services turned off the water at the road stopcock. The bill the insurance company paid out was in excess of £47k. The family had to live at a local hotel whilst the house was dried out and completely refitted. What was the cause? An un-insulated cold water pipe valve in the loft.

The water had been still for a long period and the weather had been unusually cold. The water in the pipe had frozen and expanded enough to push the copper pipe out from the olive. (A small ring of metal that forms the water seal in a compression fitting). The mains water pressure was enough to then to push the ice plug out and continue to gush into the property.

Yes it is important to insulate all the valves and elbows properly.

by Robert Cooke 22 February 2019
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.
by Robert Cooke 8 January 2019
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.
by Robert Cooke 12 December 2018
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.
by Robert Cooke 3 December 2018
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.
by Robert Cooke 23 November 2018
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).
by Robert Cooke 15 November 2018
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.
by Robert Cooke 3 November 2018
Buying property can be very stressful. You find something you like and hopefully can afford. It's not a new build so it won't come with any guarantees or warranties. 'Caveat emptor' - let the buyer beware! You'll be paying stamp duty, legal conveyance fees, valuation fee and so on so why pay out for a Building Surveyor? The house I surveyed this week was built in the 1950's, roughly 70 years ago. It had been through long drought years, wet years, cold year etc. so things will wear out. When you look around the property the main focus tends to be on what you can do with it. Settee can go there, tele' can go on the wall over there, kitchen needs a bit of an update, bathroom's not bad and the main bedroom is a reasonable size. And so it goes on. A Building Surveyor isn't interested in any of that at all. He or she will be looking at the roof lines, chimney condition, whether all the opening windows actually open easily, doors shut properly, locks actually lock, drains are working and so on. Basically all the nuts and bolts that keep the building together. The surveyor checks for anything that moves that shouldn't, has a crack in it, a chip out of it, water in it when it should be dry. Looks in spaces behind furniture, looks for strange marks, different materials, checks lights work, sockets have been wired up correctly, looks for signs of condensation, mould, mildew and a whole gambit of issues that you wouldn't dream of looking at when you view the property. The house I looked at was very neat and tidy and very clean, not a quick wash round. That made checking for condensation and moulds very easy as there were no tell-tale stains anywhere. The vendor was a keen DIYer. Very good at decorating and gardening. Not so good at complying with Regulations though. A Building Surveyor should be familiar with various styles of building and materials that would be used. If a room proportion looks out of character or sounds strange when tapped interest should be shown. Has the position of a wall been moved? If so should it should have had Building Regulation approval or a Building Notice Certificate? Many people just knock walls down to make two rooms into one. A bit of steel and plasterboard - all done. Is it safe though? Was the wall a buttress wall, part of a cruciform structure for a semi-detached? It may not have any joists on it but it is required to support another wall. What about the electrics? The vendor has re-wired the house. He wasn't a qualified electrician but had an electrician put a new consumer unit in. Checking the cabling in the loft it was clear nothing had been clipped, connectors and switches just left loose on and under the loft insulation. A qualified electrician will need to check all of the wiring and sign the work off as complying with the Building Act and Building Regulations. The UPVC windows had been foam fixed. Not a fixing screw anywhere. Do the windows need fixing screws? Were they fitted in compliance with FENSA and certificated or checked and Certificated by the Local Authority Building Control. Is it important? Yes is the short answer. It is going to cost money to remedy all the issues. Who is going to pay? The buyer or the vendor? Does it need to be remedied? Again yes. If it is a safety issue that is important. If it is something that needs to comply with Regulations then apart from being an offence if not Certified it may devalue the property especially if something collapses or starts to fall apart later. If you want to sell in the future then the conveyancing firm will be asking for the information. There is a lot more information in Buying Your First Home. It is also very useful for anyone considering moving home.
by Robert Cooke 28 October 2018
What are Property Surveys? There are many different types and lots of mis-conceptions about what they actually cover.
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