To review, my last 2 blog posts discussed 3 of our strategies for adding thermal mass to the northern side of our home in an eco-thrifty manner. (A reminder to all ya’ll Yankees up naaath, weez in ta southin hemisfiyah.) Those include: a multi-fuel stove with brick surround that will serve multiple purposes beyond thermal mass; an extra layer of gib/drywall/sheetrock on top of the existing layer (see Mas Mass); stackable green wine bottles filled with water added and removed seasonally (see Every Bit Counts). Our next two strategies include an antique cast iron claw foot bathtub and some sort of dark floor tiles/slate/polished concrete.

We picked up the tub on Trade Me (Kiwi version of Craig’s List/EBay) cheap as chips and our lovely, lovely friends Murray and Lindy picked up the tub in their truck on their way to our house for dinner.

It is a beautiful tub that needs only a little cleaning up. A mixed blessing that I only discovered while looking over our ‘Alteration to Approved Plan’ (future blog post) is that the lovely, lovely feet are destined to disappear behind an ‘impervious wall lining as per Para 9.2.3.2’ as explained in Figure 9.4 of Paragraph 9.2.4 of SH/AS1 for a ‘Simple House’ (Department of Building and Housing, 31 March, 2010).

First of all, the last sentence is the absolute truth. Could a Kiwi builder please post a comment confirming this? Second of all, if this is the regulation for a ‘Simple House,’ I am glad I am not renovating a ‘Complex House.’ But I digress.

The other side of the coin regarding covering the feet is that the ‘impervious wall lining’ would also hide everything above the feet, which is where the tub would require sanding, priming and painting. It’s a little like an old woman with varicose veins simply putting on long pants instead of having expensive surgery and wearing shorts.

The tub’s position in the bathroom was chosen specifically because it will receive direct sunlight during the 3 coldest months of the year but not during the other 9. This solar gain will make a difference – no matter how small – to the thermal comfort of our loo at zero additional cost. I’m just trying to convince my wife to paint the obligatory ‘impervious wall lining’ a dark color – maybe a nice ‘mildew green’ would serve multiple purposes. (See outcome in future blog post sometime in 2015 when the bathroom is complete.)

And finally, as we inch our way toward a day when our kitchen and dining room floors will want for something other than borer-infested ancient rimu and a patchwork of particleboard flooring, we troll Trade me, the Wanganui Chronicle and Hayward’s Auction House for a large box lot of – and this is important – matching, dark slate or tile squares.

Patience is another key to eco-thrifty building and with about 10 weeks before the floor must be laid, we can wait and see what comes up. Additionally, while looking at websites about building concrete countertops a thought occurred to me: Could we pour a thin concrete floor over the 15 square meters of the kitchen and dining room? This option could be a) cheaper, b) thicker (more massive), and c) any color we like (just add pigment). I may need to add a few more floor joists, but that would be a small price to pay. Any advice or suggestions on this one?

Peace, M.C. Estwing

I mentioned mindfulness in my first post as being central to eco-thrifty renovation. Mindfulness in this respect relates to energy consciousness, attention to detail and stewardship of materials. When I was growing up outside of Detroit, the Mormons had a TV advertisement with the tag line, ‘In life, the little things are the big things.’ Maybe Mitt Romney was thinking about that when he signed the Massachusetts Health Care Bill aka ‘Romney-Care.’ (By the way, thanks Mitt.)

Being eco-thrifty is all about the little things, as you’ll see through our ECO School projects. But in a world of cheap, abundant fossil fuel, humanity can afford to ignore them. ‘Don’t sweat the small stuff’ we’re told.

This week, while I was sweating the small stuff, on three separate occasions I was reminded of mindlessness. A local builder who has been helping me on occasion make sense of the NZ building code told me at least 300 times one day, ‘The fastest way is the best way. That’s what I reckon.’ One of those utterances came while he was wreckin’ a perfectly good ‘four-ba-two’ rafter we were removing. While I would have carefully pried it from the wall and de-nailed it for future re-use, he grabbed a circular saw and ripped through it twice and dropped it to the floor before I could protest. (Not that he would’ve listened anyway.)

(Note: I am paying him hourly, so I appreciate his need for speed, but personally I do not like to work at the pace of a conventional builder. I often call this type of attitude ‘dumpster mentality’ because most everything ends up in a dumpster which is not necessarily so eco or thrifty.)

(Sub-Note: I thrive off dumpster diving, aka tip-stripping. I have a long and beautiful relationship with it. My mindfulness thrives off of others mindlessness. My greatest joy in life is making something beautiful out of what another has considered worthless rubbish. However, I will welcome the day when ‘dumpster mentality’ has been retired.)

The second reminder came when I was taking a VERY SMALL load of demo material (not reusable, compostable or burnable) to the transfer station. I dropped off two bags, emptying our rented cargo van and then proceeded to re-fill it with shipping palettes, old bricks, 4 x 2s, concrete fence posts, grass clippings and little squares of sod. All of this material was in a small mountain in a corner of the yard, destined to be landfilled or burned. As I loaded the van, the attendant came over to see what I was up to. Referring to the sod, I joked that I was picking up my new lawn. He told me to be sure to water it when I got home. That’s when I explained that I planned to compost the grass clippings and sod in case there was any persistent herbicide and/or noxious weed seeds. He looked at me and said I should just order a load of compost and have it delivered.

And finally, the last reminder was in reference to what was supposed to be the topic of this post: thermal mass. At one of my favorite op shops (‘opportunity shops,’ ie second-hand stores) I found a pair of stackable wine bottle holders.

Minutes later, at another of my favorite op shops the woman working there commented on my recent purchase. I proudly explained my plan to incorporate a human-scale, seasonal, moveable, eco-thrifty form of thermal mass (water in green wine bottles) as part of our plan. These wine racks, I explained, would be used as a template for others that I would make from scrap wood. In multiples of 4, bottles could be stacked to any desirable height where they would be struck by the low winter sun, and then removed entirely for the summer season. To my enthusiastic description she replied, ‘Why bother. That won’t make a bit of difference. You should build a trombe wall instead.’

I told her that a trombe wall was an unrealistic option in our case and that the water-filled bottles were just one of five small measures to add mass that, cumulatively, would make a difference. Every bit counts.

If perception is reality, why is it that we perceive the world differently? Each of the well-intentioned people above was genuinely trying to be helpful by offering their sincere advice. But at its heart that advice comes from a lifetime of experience in a world of material abundance. Would their advice to me change had their life experiences been different?

Almost all environmentalists and economists describe a future with higher population and fewer resources to go around. What would someone who grew up in a developing country think of dumpster diving? What would be the advice of someone from the future, living in a resource-constrained world coping with the wastefulness of their forefathers? What’s your advice?

Peace, M.C. Estwing

As discussed in my last post, thermal mass helps buffer temperature extremes in passive solar buildings. Including it in new construction is easy, and, may I suggest, that failing to design and build climatically-appropriate passive structures is not only ignorant but borders on criminal. Climate change and peak oil will define the rest of our lives. Enough said.

Our challenge is adding mass to a 100 year-old villa built at a time when folks had more of an excuse to ignore energy efficiency. Although you have to wonder why the English immigrants to New Zealand faced their houses toward the South Pole when clearly the sun was at the back door. I thought all the psychopaths and criminals were sent to Australia.

At this stage in the project we are focusing on increasing our solar gain (as mentioned in a previous post) but plans for adding mass are being carefully laid and materials collected. At this time they include:

Our second-hand, vintage Shacklock multi-fuel cookstove will occupy the northwest-facing wall of the kitchen and include a brick surround for fire protection. The heavy iron stove and brick will only receive direct sunlight in mid-winter when the sun is low in the sky and its rays penetrate deep into the house. In summer, when the sun is high in the sky, direct light is largely excluded from the interior. In true permaculture fashion, the stove and surround will serve multiple functions: cooking, space-heating, water heating, thermal mass and disposal of unpainted wood pulled out during the renovation. Plus, the wife thinks it is cute as hell.

While not everyone can add iron and brick to their home as we plan to do, our next strategy is one that can be installed cheaply and easily by nearly anyone. If you have ever picked up a sheet of Gib (aka ‘drywall,’ ‘Sheetrock’) you know how much mass it contains – a lot! Installing an extra layer of Gib board on top of existing Gib walls is practically invisible and fairly low-cost. Our plan is to add an extra layer of Gib to as many walls as practicable in the northern corner of the house.

Added bonus: Covering up hideous wallpaper with another sheet of Gib saves hours of steaming and scraping.

The next post will include two more strategies we plan to use and one experiment in the making.

– M.C. Estwing

Last year, we did some house sitting in just such a place. At 6 a.m. when I got up for coffee and PhD research, the temperature in the kitchen was in the low teens C / 50 F. On sunny days it rose to 30+ C / 86+ F by late afternoon only to return to sweater weather (‘jumper weather’?) the next morning.

The role of thermal mass is to moderate these extremes – to buffer the system. It is like a bank account where an excess ‘wealth’ of heat can be ‘deposited’ on sunny days and ‘withdrawn’ at night. Think of a concrete stoop that has been sitting in the sun all day. It holds heat after sunset. Please note, thermal mass in passive solar design must be within the building envelope – that is, inside the glazing and the insulation.

Many new homes are built on insulated concrete slabs that can serve as thermal mass. This is smart design, but our 100 year-old villa is up on 1 meter piles with air flowing beneath the floor. The challenge is incorporating thermal mass inside our envelope in effective, attractive, eco-thrifty ways. The next post will explain some ways in which we plan to do this.

-M.C. Estwing

This picture is posted to authenticate that two real hippies were used in the making of this post. We have done our best to ensure that no hippies will be injured during the completion of this project.