How to Green up your home
Part 1: Understanding your home
Welcome to a series of blogs on How to Green Up Your Home, a common sense and practical bit of guidance on how to help make your home the energy-efficient, affordable, healthy place that it should be. As an architect from Arisaig with over a decade of experience of putting this guidance into practice on all sorts of projects I’ve found that many folk want to do something about those draughts, or reduce their heating bills, or deal with that bit of damp…but don’t trust salesmen with obvious vested interests, or the government for that matter, and aren’t sure how to go about things.
First lesson: there isn’t a one-size-fits-all approach, and simply throwing money at your house and hoping for the best just ain’t gonna work. There are, however, basic principles that everyone should know about, which should then be applied in the most appropriate way to your house. In a nutshell, houses should be warm, dry and free of any dampness, well-ventilated, free of chemicals, bright, secure, soundproof, functional and have a view out. If yours is, and does, then there’s probably no need to read any further. If not, read on…
This series of blogs will cover those aspects mentioned above and in this one I’d like you to have a look at the house you’re living in. By understanding as much as possible about how your home is put together you’ll be in a much better position to know the most appropriate way to go about making it greener and the subsequent blogs will make more sense.
So, in what sort of house do you live? It is pretty likely that there will be a range of responses: timber-framed or concrete block houses, terraces and bungalows; detached or terraced stone cottages; converted barns, byres and steadings; and perhaps even the odd station building or wooden hut. For simplicity let’s split these into ‘traditional’ buildings (i.e. those built before 1919) and ‘modern’ buildings (i.e. those built after 1919).
‘Traditional’ buildings are typified by those with solid stone walls, bedded in lime mortar, bearing straight onto the ground without any discernible foundations, and which have ground floors of timber joists raised off the ground or solid earth or concrete floors. First floor and roof structures are built from timber, and roofs are finished with slates or slates directly on sarking boards, tiles, or thatch. Stone walls tend to be lined internally with timber laths on ‘dooks’ (wooden plugs hammered into the walls), internal walls were usually brick, and the finish was invariably lime plaster with wallpaper or paint. Doors were of panelled wood construction and windows were generally wooden sash & case.
Now, it’s important to remember that these were built in the days when materials were expensive and labour was cheap, so local materials (lower transport costs) were used and put together using local skills, knowledge (especially of climatic conditions) and cultural practices which were handed down over the generations. This is why a traditional building in Lochaber will look quite different from a traditional building in, say, East Lothian or Fife.
And how do traditional buildings work? Well, unless fronting a road, many tended to face south(-ish) so that the sun would help to warm the main rooms. Windows were used to provide views, daylight and ventilation to rooms, and many internal doors had ‘deadlights’ – fixed panes of glass – above them to get light into internal spaces such as hallways. As well as being the heat source for most rooms, fireplaces and chimneys played a vital part in ventilating rooms too. Some dampness in walls is inevitable but was controlled by having land drains around the outside of the house – the space between stone walls and lath & plaster linings also helped to limit dampness getting into rooms. Raised timber floors always had a ventilated space below, which kept the timbers in good condition and limited the risk of dampness.
There tends to be very little, if any, insulation in these buildings and there are little gaps everywhere in traditional buildings, so they are draughty (paradoxically this can help keep them dry). Front and back doors usually had porches to provide some shelter when going in and out of the house and reduce draughts. Eaves could be ‘clipped’ or might have an overhang, depending on how exposed the house was to strong winds but gutters, downpipes and soil pipes were always of cast iron as they are solid, durable and can be easily repaired. Being built of predominantly ‘natural’ materials such houses tend to flex in response to temperature and moisture. They are also quite straightforward to maintain and repair.
‘Modern’ houses tend to include those built of block or brickwork, timber frame or other mass-produced materials. Its advent was the end of the Great War (and the effects of World War Two) when many traditional building skills were lost with those who had perished, and a great rebuilding effort was required. The ensuing mass production of cheap building components requiring low skill input led to the building industry we see today. This doesn’t, however, mean that the resulting buildings were of poor quality and there are some very good examples of post-war housing throughout Lochaber that will last for decades to come if looked after.
Starting at the bottom again, such houses are typified by solid concrete foundations with masonry footings bedded in cement and capped with an impermeable barrier (a DPC, or damp proof course). Concrete floors tend to be laid over a plastic membrane to prevent moisture getting through; timber joist floors tend to be fitted above a ventilated space to keep them dry. External walls usually comprise an outer layer, or ‘leaf’, of brick or blockwork (maybe painted or rendered/harled with cement) and an inner leaf of brick or blockwork with gypsum plaster finish.
Blocks and bricks are invariably bedded and pointed with cement. The two masonry leafs are separated by a ventilated cavity (hence the term ‘cavity wall’) that helps to prevent dampness from the outer leaf getting to the inner leaf. (Confusingly, many builders refer to this as ‘traditional’ construction, when it’s nothing of the sort.) In timber-framed houses, the timber frame, which is insulated nowadays, replaces the inner leaf and is usually lined internally with plasterboard. It is also usually the load-bearing (i.e. structural) bit of the wall. Internal partitions may be plastered brick or block, or timber frame with plasterboard. First floors and roof structures are usually of timber with roof finishes of slate or concrete tile over a plastic membrane. There might be insulation in the floor, walls or roof, but its performance depends as much as on how well it was fitted as how much there is: there’s no point in having a foot of insulation in one bit of your loft and none anywhere else.
Other than the timber framing, these materials tend to be very hard, inflexible and not that straightforward to repair, which you may already have found on your own house. Modern houses also tend to rely heavily on plastic membranes to prevent moisture and water movement, rather than good design and understanding. The construction of houses built of such materials coincides with the rise in car ownership, which is why it’s common to find similar house designs orientated around road layouts rather than the more important aspects of wind direction, solar gains, views, surface water run-off, privacy etc.
So, whether you’re in a traditional building or a modern building, go outside and give your house a quick look over – how clear are your airbricks? Where do you think those draughts are coming from? Why is one part of your house so much colder than the other? You might be able to take an educated guess at the answers to these questions now and we’ll explore look at them in more detail in the next article on Getting the basics right – dry boots, a warm coat, a good hat. Bye for now.
Sam Foster, Sam Foster Architects