Wallpaper, warmth and the plaster cast of a toilet roll.

The big task of our current house renovation has been scraping off a century of interior design ideas that previous residents had found attractive.  I quite liked some fragments of wallpaper which have been found at the back of cupboards and under floorboards but I'm not certain about the dark green woodwork.   Most of the wallpapers are thick and heavy and may have been two layers deep at some point.  This made me wonder if these heavy papers were chosen for their thermal properties as much as their decorative value.

The starting point for the investigation was the plaster cast of a short length of toilet roll.  The idea was to create a section of wall, albeit without the supporting brickwork.  Embedded in the plaster was thermistor which allowed the internal temperature of the wall to be measured.

The idea was to place a sample of wallpaper between a heat source and the section of plaster and measure the temperature rise with the thermistor.  After some messing with kitchen utensils, the selected heat source was a flat bottomed coffee mug of just boiled water.  This is a diagram of the apparatus:

The implementation was not as neat as the diagram and for that reason no photo has been included. This setup was not going to capable of providing the data to estimate thermal conductivity (e.g. U values), but it was able to indicate the relative insulating effects of various wallcoverings. The methodology was to place a mug of freshly boiled water on top of the wallpaper and take measurements of the thermistor's resistance at one minute intervals.  These were then turned into a warming curve, the lower the temperature rise, the greater the insulating effect of the wallcovering.  The results are shown in the graph below:

The base case is just the plaster surface, a layer of lining paper had some moderate insulating effect, but a sample of thick wallpaper clearly reduced the flow of heat into the plaster.  Neither was a effective as a 2 mm layer of polystyrene.  So it might be reasonable to assume that wallpaper was an element in the house's energy economy.

As a schoolboy, I remember being taken/dragged around some stately piles whose walls were lined with portraits of dignified people, which I now realise may have have been quite degenerate (I'm not jealous).  In such places, the smaller rooms were hung with tapestries or lined with fabric to keep the place cosy, so heavy wall paper is just the mass market descendant of the tapestry.

Victorian and Edwardian houses were designed to be porous (i.e. drafty).  I'm not fully certain of the mechanism, but sealing/insulating walls can become a source of damp which degrades the bond between the top and base coats of plaster or the supporting brickwork.

The streets were paved with wood (from Australia)

Last year I had to repair a retaining wall which had done a good job for the better part of a century but poor quality bricks and and a large measure of town ash in the mortar finally caused it to succumb to weather and plant damage.  It is probable that the bricks were made with local clay mixed with ash and fired by lop and top from nearby woods.  I attempted to acquire some English bricks for the rebuild, but at the time there was a brick shortage and I had to use ones imported from Europe.  The new bricks were probably fired in a kiln fuelled by natural gas.  Whilst the new bricks were a big upgrade on the old ones, they were the product of an international industry, not a local one.  This started me thinking what other local materials were in use around 1900 when the house was built.

In Sussex, flint has been used for walls and road making for centuries.  As few weeks back, a section asphalt got worn away in the street outside the revealing what might be the remains of the original flint surface.  I have read that horse drawn carts took the town's filth out to farms in the countryside and returned with a load of flints for urban construction.  Evidently, flint roads  are well suited to horse traffic as the action of the hoofs compacts the surface.  In contrast, the braking and acceleration of motor vehicles causes rapid degradation.

Iron shod horses moving along a flint road create traffic noise. One way of reducing this was to surface roads in residential areas with wooden blocks sealed with tar (from the local gas works?).  Roads like this can be found in many cities in Europe and North America.  The section below survived into the 21st century, possibly having been resurfaced several times:

The material discarded during the upgrading of urban roads sometimes get recycled as filling for holes in rural roads and tracks.  Whilst out walking along a bridleway, I picked this wooden block from a pile of debris

A relative who had grown up in East London had told me about these blocks, being a combination of wood and tar they were a popular top-up for the domestic coal supply, being a combination of wood and tar they burnt well.  Whilst reading around for this post, I came across the Wikipedia article at the end of the link shown at the bottom of the page, this suggests that a lot of the wood used for these blocks was imported from Australia.

What started as a search for local connections has ended up with a reference to forests on the other side of the world.

Wikipedia Article

Eucalyptus marginata

Drifting back in time

For some time I have been renovating my four bedroom Edwardian semi which was built around 1901.  A close personal relationship has grown up between us but I don't want this post to be a sugar sweet dose of nostalgia.  At the time it was built society and technology were more than a century apart from where they are now.

The Ground Floor

It's reasonable to assume that the smallest bedroom, which is slightly apart from the other three was intended for a cook/housekeeper, if this is correct it is probable that this role was filled by a woman.  Domestic service has dropped off the list of desirable jobs for women and when I look at my daughter and her contemporaries which include lawyers, architects, doctors, designers, teachers I feel a deep sense of gratitude for that element of social change (not certain about the lawyers?).  To get back to the point, keeping the house functioning for a family, probably was a full time job.  Maintaining six open fires and a cooking range was not a trivial task, let alone cooking and cleaning.

Today, within easy walking distance are two supermarkets, whilst these do sell fruit, veg., meat etc., the bulk of the shelf space is given over to prepared food and this is what many people pick up on their way home.  In 1901, meals would have been cooked from scratch and ingredients would have made up a greater proportion of shop sales than they do today.  We moved to the area in the early 1980s when some old style shops were still trading, but fading fast.  One of these was a family run grocery store which had been built when the neighbourhood was being developed.  The last owner had grown old with his customers and felt no desire to change so the stock was tins, dry goods, bacon sliced to order, cheese cut into portions with a wire and biscuits in boxes.  He had been in Malta whilst it was under siege during the second world war.  I remember him as a practical man who had a natural authority who gave me some good advice on dealing with a household infestation which his wartime experiences had given him some experience.  Oddly, my first office was the space above that shop.  A short walk away was a baker supplying cakes and bread and nearby was a green grocer and a butcher.  Today, most shopping is done at supermarket and the goods bought home either in the family car or in box shaped vans, both of which embed the motor vehicle into the domestic economy.

Where the bedrooms are

The house had a large volume of space for food storage.  This is split between a large cupboard which now contains the central heating system and a larder which was demolished to make way for a fitted kitchen.  This was made of chipboard and crumbled during our first week of occupancy, in contrast, the cupboards in the original kitchen still look good after 110 years.  This is a guess, but there could be enough food in the house to keep the occupants fed for several days.  The larder may have had some long term storage role.  Family oral and written history suggests that most households grew some fruit and vegetables if they had the space.  A cool, dry space would have allowed stuff to be stored, for example, carrots can be kept for several weeks in dry sand and tomatoes will ripen during September and October.  In addition, produce would have been bought for preserving.  Even today, supermarkets stock preserving sugar and jars of vinegar for a brief period during late summer.  In keeping with a family tradition, my wife makes marmalade from Seville Oranges in early February each year.    All these things take time and effort and can become a full time job.

Next to the larder in the scullery was the coal store which seems to have had a capacity of about two tons or more, This might have kept the house warm during December and January.  Whilst the soot from coal fires, led to the creation of smoke free zones in the 1960s to combat smogs, they have two interesting economic features which are relevant today.  The first is that they allow zoning, which simply means heating the rooms you are using, many modern gas fuelled central heating systems heat the whole house which can make them inefficient. Central heating systems can be zoned, but it does not seem to be a common feature.  Secondly a local market existed for coal in a way that it does not for gas and electricity.  Most reasonably sized towns would have had several coal merchants who would compete with each other.  You can haggle with a coal merchant in a way that is not equivalent to swapping your gas supplier.

Coal fires and gas boilers differ in at least one respect.  For a coal fire to work, it needs a supply of air or drafts as they are sometimes known.  A charitable view of drafts is that they were also a form or ventilation which bought health benefits at a time when respiratory diseases were common and potentially fatal.  My mother would put library books in the oven as a defence against TB, this  made me fearful when it was time to take them back in case I had to explain charred dust jackets or evidence of rice pudding.  Many modern houses are pressure tested to ensure that drafts have become and endangered species, the logic being that once you have heated the air, you want to sit in it, not feel it ebb away through rattling sash windows and under ill fitting doors.

The house was built with an extensive system of gas pipes.  It seems that the living and dining rooms where lit by gas chandeliers hanging from the ceiling, whilst the other rooms were lit with mantles, usually one is over the fire place and another at some random location which probably suited the first owner.  The gas lighting was short lived, bits of newspaper found under the floorboards suggest that electric wiring was installed in 1911.  Whilst the gas lighting was blanked off at this time, it seems that the coal fires, may have been replaced or augmented by gas.  Lighting a coal fire with old newspaper and kindling wood is time consuming.  A quick and easy alternative is the gas poker with one of these devices you simply fill the grate with coal, light the gas poker and plunge it into the fuel and leave it there until the coal is burning.  Gas and oil lamps need regular cleaning an maintenance whilst electric lights just have to be replaced after a few hundred hours of use.  The house has about twenty light sockets and in the days of incandescent bulbs, there was always one and probably two bulbs that needed replacing, now with LED lighting, failures are rare.

There have been four generations of electric wiring, the current one whilst not being very tidy, seems to be the most robust.  The first system was based on rubber sheathed wires mounted in wooden conduits, some of this was put in by someone with reasonable carpentry skills.  At some point, the wood was replaced by metal tubes, probably because the insulation had improved, this in turn was replaced by polythene sheathed conductors and the current cables are covered in PVC.

Domestic hot water has been a challenge.  I'm guessing, but hot water for the kitchen came from the range and hot bath water was supplied by a gas fired geyser.  I have a horror of these devices which was  acquired during my early post-student days when I was once denied a bath by the presence of a dead pigeon in the flue and my hygiene was determined by the direction of the wind.  Modern ones work properly.  My dislike of geysers may have been shared by an earlier owner who had installed a range or stove with a back boiler.   The hot water produced by this contraption reached the bathroom by an iron pipe, by the time it was decommissioned around 1980, the bath taps must have run a slow trickle of dark red water.  The inside of the pipe was blocked with rust and limescale.  The next upgrade appears to have been gas boiler and hot water cylinder with a gravity flow system, the efficiency of this was somewhere in the range 20 - 40%.  A pumped system has increased the efficiency, but there is still room for improvement.

The picture I'm trying to paint is one of change, some of it good, some of it debatable.  Whilst I don't know the people who worked on the house, I know a little of their smoking habits.  The men who built the house smoked clay pipes (oddly my wife has one), I have a few bowls and fragments of stem turn up when least expected.  By the 1950s, the high tar brands were offering filter tipped versions of the gaspers and a few discarded packets were dropped between the rafters.

Soil Moisture Content

I've been collecting soil temperatures once a week at a randomly selected spot in my back yard for just over two years, some days the soil turns to mud as soon as I step on it and during the summer regular watering is needed to stop it turning into dust.  I became curious to know how the water content varied over the year.

The methodology is very simple.  Around sunset on most Sunday afternoons, I take an empty and washed dog food tin which has been weighed and half fill it with earth after which it is weighed again.  This being winter, we heat one room with a coal fire, this burns down overnight, by morning there is a pile of hot ash in the grate.  These ashes are piled up around the tin and by evening, the soil is dry and crumbles into dust when rubbed between the fingers.  The final step before the soil is returned to the garden is to weigh it a third time.  When spring arrives, I will simply leave the tin in a warm place until it's weight stabilises.

The weather during January can best be described as winter, at the beginning of the month it was wet winter and at the end of the month it has been cold winter (relative to places like Scotland and New York, winter in the south of England is just mild).  During this time, the moisture content from the sample area has remained constant at around 25%.

At present, I have no idea what the range of values should be.  The garden is a series of terraces on a slope, the sample is taken at the top where the drainage is good.  The lowest terrace often becomes water logged so there is clearly some significant variation over a small area.