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Sandstone Tiny House

PostPosted: Sun Oct 28, 2018 11:39 am
by Hastings
Hi everyone.
New here as of last week and have been giving them a headache over on the solar thread, trying to learn the basics of solar power. :lol:
Reason for divulging my plans is to get positive feedback from persons who have actually built using alternative materials or have information that will help me achieve my goals, so here goes.
Being a retired builder gives me a head start on what materials/methodology are suitable for the construction of a sandstone tiny house near Gloucester NSW.
The only threat to these plans are short minded authorities who are book ended into their own unimaginative spaces, although I have an unfilled dam that will take care of that little problem.
Having said that, I'm looking for an open minded draughty who can draw up the plans, so anyone on here got a friend? Really.
Many years ago on a very very hot day, I visited the Berrima Courthouse built in 1839. Being completely built out of sandstone, gave reason why the temperature inside was 15 degrees cooler than out. The face of the stone was cool to touch and even outside too as it was not like bricks, where they can get so hot that you can burn your hand upon touching.
So, given our propensity towards a warming globe, Im building the structure to contend with 40 degree days, not the cold.
In winter the sandstone will act as a thermal mass to a degree, as its not the best rock for heat gain, due to air gaps within the grain, however the stone will absorb some of the heat given off by the integrated wood fire. Much like reverse brick veneer.
The structure will be around 35-40 sq mtrs tops, using 250-300 thick x same high, sandstone blocks with a sandwich panel roof. Yes, a very small house, but after having big homes that were energy pigs, I'm totally going the opposite way.
Roof may have to be changed due to BAL as the glue laminating the steel to the core will melt in a severe fire event and slide completely off, leaving the occupants and structure exposed.
Floor will be polished concrete for ease of maintenance and coolness. In Winter, rugs will be the du jour.
Although, Im looking into thermal siphoning for underfloor heating, however it may not be viable (solar) if a pump has to be employed due to the rising nature of hot water and not the other way. (Anyone?)
The only timber utilised will be door and window frames if the BAL will allow as I'd like to use HWD sleepers. (BAL HWD approved timber)
In addition to the normal windows, I will use perspex shields against the hot Nth Westers, which supplies the heat source for 40 degree days.These will clip in place and provide a small air gap to assist passive cooling features built into the house on the eastern and southern aspects.Just another little defence system to reduce convection by radiant heat.
The house will have a verandah on two sides. On the southern aspect a small shower/toilet/laundry will be housed at the western end of the verandah.
This will provide a barrier from the western sun in addition to the windowless, western wall.
I'm still trying to convince my wife, that you can swing a cat inside the home without hitting a wall, but that remains to be seen. You should have seen her face when I explained that the toilet would be outside.......priceless. :lol:
Having the bathroom outside has many advantages; Smell, dampness, construction methods and space. Apart from the modern theme that one must toilet inside, I just can't justify having such a smelly place within ones home, especially in a tiny home like this.
Power will be solar as the power lines are a rugged 5klms away. They will be mounted on a rotatable frame in the paddock about 12 mtrs away from the house, as I don't really want to see them. The batteries and equipment will be housed in a lean to off the back of the house. Running power cables is an issue with solid walls, so I will run metal conduit down the inside walls for PPs. Not unlike like federation houses.
Wont need too many, so not really an issue. A wood cooker will be employed for cooking and additional heating duties. As said earlier, under slab heating is still very much on the books.
The fireplace is still under discussion due to inefficiencies of some designs. We have had both slow combustion and open fires, however I believe with the right design of the chimney, I can achieve the least amount of heat loss and given the compact space, even a poorly designed fireplace will give off enough heat.
A fair amount of thought will be given on this subject, as this will be the focal point of our home.
Well thats it in a nutshell. Floor, walls, roof have all been accounted for, so if I haven't left anything off, its over and out for now.

Re: Sandstone Tiny House

PostPosted: Sun Oct 28, 2018 2:05 pm
by jules
Great post, umm err "Hastings" :) and your project looks great!

A comment on just one part of your post ... I built a fireplace in stone using Ken Kerns design ideas. [Ken Kern wrote a number of books about what could be called alternate building.] Most open fireplaces are totally horrible and can actually extract more heat from a house than they put in. You've possibly looked at various designs already but just getting the proportions right, not having them too deep, not using silly shelves or stepped chimneys that can't draw, getting the slope and reflection on the back right and possibly using a steel "box" around the whole thing to heat air for circulation are all factors that make a huge difference.


addition: Could I also suggest that you have a look at the Rainbow Power Co site

They have been around for ever and have various plans for different sized systems, inc smaller ones like you're planning.

Re: Sandstone Tiny House

PostPosted: Sun Oct 28, 2018 6:00 pm
by Hastings
Thanks Jules.
You are exactly right in heeding caution when constructing stone fireplaces.
There are some great sites, that detail the "correct" method of constructing, but still is an art form in itself.
We've had an infill/surround type fire before, but you just can't beat an open fire, bear skin rug and a willing subject to complete the dream.
I'm missing just one component for that to happen and I will let you work that one out...... ;)
I'm also well aware of the RPC as I lived near Murwillumbah in a previous life.
Thanks for reading.

Re: Sandstone Tiny House

PostPosted: Sun Oct 28, 2018 6:29 pm
by Hastings
Jules, Ive just read a preface from your man Ken Kearns.
It turns out that the fireplace design I was referring to is his.... ha ha
Amazing that back in 1972, he had the smarts on housing, that most uni people today just don't grasp.
Thank you again for your interest.

Re: Sandstone Tiny House

PostPosted: Mon Oct 29, 2018 7:30 am
by jaahn
Hastings :D
A very interesting house. I guess you have given it some thought in lots of areas. There are lots of ideas on passive solar, and how to make it work. But sometimes people seem to mix them up so some cancel out others. You need to have clear goals and work to them.

The other thing that is confusing sometimes is the difference between thermal heat transfer and thermal mass. Just because a material has high thermal mass, it does not mean it has good insulation properties. A good blend of these properties is important. Or a blend of two types of materials used together to achieve the goal. That is what we do in 'normal' houses. :shock:

The climate in our part of the world means that the sun can provide most/all of the heating in winter, as you know, and excluding it in summer can be most productive, and night cooling is available most times. But this all needs good window planning and shading. No doubt you have read books/ information to calculate that.

Another aspect that I see you have mentioned is a rotating solar array. In the solar threads there is a description of a "Virtual Tracker" that Gordon built and documented instead of a movable one. Read all about it there. :roll:

Re: Sandstone Tiny House

PostPosted: Wed Oct 31, 2018 6:52 am
by Hastings
Thank Jaan, I'll check out Gordon's post.

Re: Sandstone Tiny House

PostPosted: Thu Nov 01, 2018 6:16 am
by davidg
jaahn wrote:I see you have mentioned is a rotating solar array

I designed an array tracker system. I did not build it.

Virtual tracking is cheaper to do frankly and since nothing moves and no motors in volved there is little to maintain. However one day if it really takes my fancy I might build it, swinging 20 panels in 2 axis would be very cool 8-) to watch. Oh and custom designed slew ring arrangement with tilting pivot point that takes both high non linear compression and tension. The other biggest issue design wise was making sure it stayed attached to the ground, micro piles woundup meeting the issue, they just needed to be wound into the ground so they had an uplift resistance of about 10+ tonnes for each leg as the array would sit on a 3m high tripod to hold it in place. It is a pretty big sail otherwise. :D

Re: Sandstone Tiny House

PostPosted: Sat Nov 03, 2018 5:13 am
by Hastings
I was thinking something a little less techy, but I get here you are coming from......
I'm still torn over the cost of lithium/AGM...... :lol: