By: Simon Brooke :: 20 May 2020
These are detailed notes from my reading of Chapter 2, 'Buildings', of Common Weal's The Common Home Plan. I should start by saying I strongly deprecate publishing documents like this as PDF, it is such a bad format for any critical purpose! Also note that the PDF linked above from the website has slightly different page numbering from the printed version — in my notes, I have used the page numbers from the printed version.
The first point to make I generally agree with this document. Where I haven't commented, assume I'm in agreement! What follows ia mainly nit-picking.
"As soon as the Common Home Plan is agreed, all new houses must be ready for district heating — unless they are 'Energy Neutral' so require no net heating" — P 31
In rural areas? Seriously?
"New-build houses which are off the future heating grid must be built with renewable heating systems installed" — P 31
Better!
"One of the best ways to reduce the embedded carbon of a building is to ensure it has a long lifespan. Many of today's buildings are built to low quality standards and have a short planned lifecycle" — P 31
"This is incredibly harmful and no buildings should be designed with anything less than a 60-year projected lifecycle (and most should aim for 100 years and more)" — P31
Good points — and argues against my own 'low impact, low cost, light hearted' approach.
"new-build activity should be reduced altogether through a strategy of 'repair and renovate first' — existing buildings have already embedded the carbon of construction, so unless there are very specific reasons should always be renovated rather than demolished" — P32
OK, strongly disagree. Many of Scotland's older existing dwellings are built of random rubble using mortar made with sand and baked seashells from beaches — the resulting mortar is salty and hydrophilic, resulting in permanently damp structures which are both hard to heat and promote fungal and mould growth leading to spore-laden internal air. This is really bad for health. These buildings are also extraordinarily thermally inefficient, and making them thermally efficient is almost certainly more energy intensive than tearing them down and starting again.
Of our more recent housing stock, much is of such poor quality that there's barely any need to tear it down — it will fall apart anyway before very long.
All this is acknowledged in the next paragraph:
"There are approximately 2.5 million households [sic - I think what is meant is 'dwellings'] in Scotland at varying degrees of energy efficiency and with a wide range of technical issues to be addressed. Achieving maximal thermal performance is likely to be unachievable in many houses and in many where it might be technically achievable, getting the last ten per cent or so of efficiency may be so expensive as to be prohibitive" — P 32
Note that I'm not saying 'rip all Scotland's housing stock down and rebuild it' — there are very many well built, graceful buildings throughout the country, especially from the Georgian and Victorian periods, where attention to glazing, draughtproofing, damp course and roof insulation would result in buildings which are reasonably efficient, particularly in a context of widespread district heating schemes, and where the grace and spaciousness of the living space will to some extent offset the slightly higher cost of heating.
"completing a target 60,000 installations a year in the early years would be achieved with a workforce of approximately 6,000 people. Roughly ten per cent of these jobs would be at managerial and senior technical level, about 30 per cent at skilled trades level (particularly joiners and electricians) and the remainder semi-skilled (trained on installation of insulation and draught-proofing)" — P 33
Semi-skilled work in draughtproofing and insulating homes could easily be done by householders, working together with neighbours and with support from a few trained tradespeople. I see two major benefits from involving people in the construction and maintenance of their own homes: it reduces cost, and, more importantly, it builds their self-confidence, their ability to undertake projects, their sense of ownership of and responsibility for the dwelling; and, if done communally, their sense of community cohesion. I appreciate that part of what Our Common Home is seeking to do is to create well-paid jobs, but in an era of (hopefully) Universal Basic Income, I cannot help feeling that community empowerment may be of greater benefit to the nation than 4,000 semi-skilled jobs.
"However, small businesses (and in some circumstances, some landlords) will need financial support to achieve this. Discussion with the private sector on establishing a regime fair to all should begin immediately after the Common Home Plan is agreed." — P35
Please let us not offer state aid to private landlords. Let us instead require them to carry out the work within a stated period, allow the market value of unimproved housing stock to fall through the floor, and then take it over as public housing as low cost. We have enough vermin in society without fattening them further on public money.
"Dowel Laminated Timber (Dowel-Lam or Brettstapel) is fabricated from planks of softwood timber stacked and then connected under pressure with dowels, enabling lower grade timer to be formed into load-bearing panels.
Nail Laminated Timber (NLT) is similar to Dowel-Lam but with nails rather than dowels connecting the timber planks." — P36
Generally I'm of the view that for long term carbon sequestration dowel-lam is preferable to nail laminated timber because it is much easier/safer to dismantle and re-use. Nailed timber is more likely to be smashed up and burned because no-one is going to want to risk damage to saws in cutting it into new shapes.
"Certainly domestic housing can easily be built using only organic materials." — P36
I don't believe this is currently true, much as I would like it to be. Specifically I believe that we still need to use non-organic materials for
- Glazing — this is the big one. As we build houses for better insulation and better passive solar gain, we're going to need to use (much) more glazing materials — and I am not currently aware of an organic substitute for glass. Glass is not, of course, a toxic material, but recycling glass is expensive of energy.
- Electrical conduction — currently we use metals to conduct electricity, and thermoplastics to insulate the conductors. Organic insulators are possible, both cotton and rubber have historically been used, but may be undesirable because it may be difficult to know when their performance has degraded beyond a safe limit. I'm not aware of an organic conductor which is anything like as efficient as metals.
- Distribution of fluids — we currently use metals and thermoplastics for pipework to distribute water and gasses to where they are to be used within a building, and to carry waste water away. As we adopt district heating, we'll need a considerable amount of extra pipework. While historically wooden pipes have been used, and bamboo pipes are still used in some places, neither timber nor bamboo has the service life as pipework of metal or thermoplastic, and again I'm not aware of any current organic replacement.
I also think that the use of fieldstone in foundations, thermal storage, and gabions, and of masoned stone in facings where desired, is sensible use of a widely available material which has a low energy cost. Obviously the use of a cement or kilned lime mortar is much more problematic.
I strongly believe that use of organic materials is a desideratum to aim at wherever possible.
"concrete, metals and plastics can all be recovered and recycled" — P36
No, honestly, concrete can't, at any reasonable energy cost. Where mass is required, e.g. in foundations, ground anchoring and thermal storage, stone in gabions is almost always going to be a better and more reusable solution.
In summary, my criticisms are all detail nit-picking. I agree with and support 90% of this document.
Not mentioned: the use of agricultural byproducts — especially straw and sheep's wool — as insulating materials. Sheep's wool is especially something which should be seen as a priority, as at present a great deal of it is burned every year in Scotland as there is no economic market for it; but it is an excellent insulant, which, when treated to protect from insect infestation (and possibly to retard flammability) could be used everywhere fibreglass insulation is currently used.
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