Building a straw-bale house

There are a number of reasons we have chosen to build a straw-bale house:  to downsize and retire to a smaller property; to be practically involved in the building process and to build an inexpensive home; to continue a lifetime of care and concern for the natural environment and to live in a house that is ecologically sustainable with a zero carbon footprint. 

Straw has amazing properties: it is warm, breathable, extremely insulating, and thermally and acoustically efficient. It is also structurally strong. Used with lime and clay plasters, a straw house is healthy, non-toxic and hygienic, giving a cosy and warm space in which to live. It is quick to build, affordable, fire resistant and CO2 negative. (The CO2 remains stored in the straw for the life of the house).  Often the straw (and the other natural materials used such as wood, sheep’s wool and hemp) can be locally sourced thus saving on transport costs.  Very little heating is required as straw stores latent heat so is very cost effective.  Straw is also beautiful and tactile!  All the materials come from the earth and can return to the earth in a natural cycle.

The building of a straw house takes a lot of labour and is a great way to build communities of like-minded folk, all working together outside, learning and sharing skills, and building a beautiful home. Great fun.

If following this path encourages and inspires others, and shows what can be done with renewable and local resources, and that building a house doesn’t have to ‘cost the Earth’, then that will be our small contribution to a more sustainable world.

For anyone who is interested in the building of straw-bale houses, Barbara Jones’ book ‘Building with Straw bales – A practical manual for self-builders and architects’ (Green Books 2015) is an excellent read.  Barbara is a pioneer of straw-bale building and it is a very inspiring book.  She also runs courses in straw-bale building and lime and clay plasters (in Scotland and England) from her company School of Natural Building.

If anyone reading this would like to be involved in our straw-bale house building (depending on the Coronavirus, 2021 or 2022) then please get in touch via Kasha at Sustainable Selkirk. We welcome all those who are interested in a more sustainable way of making homes. JA November 2020.

PVs on my roof

When I moved house, I was keen to be as energy efficient as possible. Solar photovoltaic panels were suggested on my home energy report. I was lucky to hear about Sustainable Selkirk, and have a home energy assessment done. After discussing SolarPV panels with the Home Energy Adviser and attending an online meeting I decided to go ahead and get Solar panels.

The local company I approached was very helpful. The director came to discuss how the system worked, and the benefits, and was able to explain it all in an understandable way. The work was done very quickly. The panels were put up on the roof with very little disruption, the workmen were mainly outside. The internal connections, controls and storage battery were put in a couple of days later. It took longer than expected because of some unusual electrical problems in my house. The engineer and electrician were very patient and worked hard to sort out the problems. They made sure I was kept informed of what was happening. Once it was installed everything was explained, and any questions, however silly, were answered. As it is November (2020) I do not expect my Solar panels will produce much energy, but there have been some sunny days when I could see there has been some electricity produced. I have every confidence that if I have any questions or problems I will get the answers or support I need from the company. I am pleasantly surprised how quick and easy it has been to get my Solar panels. (SK)

My house, my changes …

My wife and I moved into our house in November 2009. The weather was terrible. Days of lashing rain turned into snow and ice, stress testing the heating system and our determination to enjoy the new space. The house is large and detached and built in the mid 70s when insulation was a luxury, not a given. As newly-weds in 1973 in our rented flat we would put on our coats in winter to go from the living room to the kitchen where sometimes the water pipes would be frozen. At the time we considered this as normal, and since the flat had a bathroom and a small kitchen it was better than the house, I grew up in.

However, expectations and standards have progressed since then and there is no going back even if in doing so, I might help save the planet by minimising our energy footprint.

The house had some insulation in the attic, cavity filled walls, double glazing, oil fired central heating and an open fire in the living room. Nothing much to complain about. But it still felt less than warm especially during the day when the heating was off. Maybe because of our earlier inurement to being cold we had both since got used to and enjoyed staying warm and being able to move around in comfort. Not for us our neighbours’ concern with saving heating bills or switching it off for the season.

We started to make improvements.

First was an AGA for the kitchen This had nothing to do with a preferred mode of cooking, neither of us were foodies or even particularly interested in cooking. It was to have something warm and friendly, great to come down to in the morning, and comforting for the whole day. We chose an electric one. It is programmable but mainly on. I have no idea what it costs to run. I would trade the cost of something else to keep it as the heart of the home. Probably food!

We replaced the living room fire, just in time for our first Christmas. The open fire was a Baxi, an expensive object of desire in the 60’s and 70’s but actually not very efficient with most of the heat going up the chimney. We bought a new, state of the art, glass-fronted, Danish Morso. What a treat. Very efficient. The chimney has only been swept twice since then and hardly needed to be. We only had to clear the ash about twice a year and often had to open the patio doors when it was going.

So, we were comfortable and would not need to do much more.

However, it seemed like a good investment to conserve energy by improving the insulation.

I investigated ways to do this. The best place for insulation is on the outside faces of the walls but this is expensive and creates a lot of awkward details at chimneys, eaves, etc.

The main problem of adding insulation internally is that it can encourage and conceal a build up of moisture in places within the wall-interstitial condensation.

Our solution was to line the inside of the whole ground floor with 100mm sheep’s wool insulation between new studs. Sheep’s wool absorbs and releases moisture. We sliced the ends of partitions to allow the insulation to be continuous along the external walls. We left the chimney breast uninsulated.

We then added an (expensive) moisture control membrane throughout. To minimise later penetration of the membrane we added smaller straps to create a gap between the membrane and the new plasterboard and placed wiring and plumbing to radiators in the gap. This seems to have worked well.

At much the same time we insulated the attic with Ecotherm, taking advantage of a limited grant available at the time and then adding a lot more. The attic now looks like a luxurious duvet albeit a pretty scratchy one.

The toughest bit was adding insulation under the suspended timber floor. This work was made horrendously difficult because of our decision to lay oak flooring on top of the nice stable chipboard flooring leaving it undisturbed. I will never again in my life crawl under a floor for weeks on end stapling netting and imprisoning fibrous quilt then insulating pipework. That said it has made a huge improvement.

We did not insulate the walls on the upper floor. The positions of doors and cupboards makes that more complicated. There seems to be enough heat percolating up from below and in any case the rooms have a nice thick woolly hat just above them.

The front of the house had 11 sash and case windows built into the original house. At the time they would have had single glazing as was the norm and this had been replaced with double glazing rather clumsily done. The rear windows had been replaced with hardwood tilt and turn windows before we came and were fine.

We had repaired the front windows, largely by replacing rotting cills and some re-cording, and done a first round of painting. The thought of continuing to maintain them did not appeal so we investigated replacements either as wood by Ventrola an industry standard, or in pvc. PVC won on a fine balance. The new windows are technically very good and require no maintenance. The detailing is considerably less refined than a well-crafted Georgian window would be and the catches are crude by comparison. However, the fact that they are sash and case and match the original proportions seems like the right gesture given the house is next to a conservation area.

The next move in the quest to improve the planet one house at a time came with the installation of photovoltaic panels on the roof. You may remember that feed-in tariffs were available to encourage their use and that the tariffs were successively reduced as the take-up increased. We got our panels completed just in time before a change in tariff. The electricity is sold into the grid. After about 8 years the income now exceeds the cost to install them so they are in profit and have given no trouble over the years except perhaps in a hard winter when snow and ice tend to dive off this part of the roof faster than elsewhere.

One morning the original oil-fired central heating boiler decided to end its life. We had done some homework on alternative heating systems with a view to doing the right thing by finding something more environmentally friendly than oil. All had their flaws. A biomass boiler was expensive and large and the acquiring, handling, pricing reliability and storage of fuel seemed energy-sapping itself. So that idea was parked. Then there was the idea of a heat pump. A ground source heat pump might do the job but would require much of the garden to be dug up. Air source heat pumps seemed inadequate. Internal heat recovery systems looked to be difficult to tune and supervise. None of these are bad ideas and in fact some of them might be hunky dory. They do work best with a large slow heating area such as underfloor heating. Ceiling heating seems to have gone out of fashion. However, with the sudden demise of the boiler the easiest solution was to replace it with a modern efficient version that also responded to external temperature. So that happened. The cost was reasonable and the work not disruptive. The system is pressurised and eliminated the thank in the attic. I guess the next right move will be to go electric probably by replacing the wet system of radiators with panels and I expect a super-duper remote sensoring and control system operated via mobile phone or whatever. It seems a shame to replace the oil-fired boiler when it is still young and vigorous. How altruistic do I feel and more important how does my bank manager feel?

The hot water cylinder gave up with a dramatic flood and has been replaced by a much bigger efficiently insulated one. My family are grown up and far off with families of their own so having so much hot water available is probably an indulgence. Great when they visit. Finally, I changed my electricity supplier to one that purports to use only renewable energy. Not sure how that is done but they seem trustworthy, efficient and communicative to the point of being chatty, so that seems to be ok.  Almost everything I pay for is done as a direct debit in many cases as a set monthly amount that gets reviewed every year.