Passive cottage project

Mike Haasl wrote:Welcome Suleyman, that's a meaty first post!
HI MIKE!
THANK YOU VERY MUCH  FOR YOUR REPLY.

How easy is it to dig where you plan to put the cottage?  
WHAT I THINK IS THAT IT IS A HARDPAN LONG TILLED CLAY SOIL ON LIMESTONE. I HAVE NOT GET THE SOIL TESTING DONE, YET. BUT I DID SIMPLE TESTS LIKE JAR AND RIBBON TEST. AND MORE, I HAVE GET SEVERAL SWALES DUG. ALTHOUGH IT WAS HARD ON THE HIGHER SIDE OF THE LAND, IT WOULD NOT BE HARD ON THE PLACE WHERE COTTAGE WILL BE.

Have you calculated how much water you'll need to collect for the year and if your roof can collect that much?  I think the tank will need to be at least partially buried to avoid freezing in the winter.  
I HAVE TO DO IT, BUT NOT DONE IT YET

My assumption is that radon comes up from the ground when there's lots of granite down there.  I'm not so sure that you'd get an appreciable amount of radon off of granite building blocks but I'm not sure....
YOU MIGHT BE RİGHT. I SEARCHED IN THE NET, BUT COULD NOT FIND ANYTHING SAYING NEGATIVE IF I USE THEM ON THE WALLS.

I tend to try to copy historical building techniques and adapt them to a passive or efficient modern design.  What kind of foundations, walls and roofs did people do in your area 200 years ago?  
THAT IS A GOOD POINT. THANK YOU. I WILL CHECK.

Earthships are a design that seems to work well in those temperature ranges.  Maybe you could simulate one with granite instead of old tires?
WITH MY LIMITED KNOWLEDGE FROM WHAT I READ AND SAW, I CAN SAY THAT THE SOIL IS GOOD FOR ADOBE. I HAVE DONE SOME SMALL BALLS AND MADE SIMPLE PRESSURE AND DROP TESTS. HOWEVER, I AM ALONE WITHOUT ANY SUPPORTIVE COMMUNITY ARROUND. IT WOULD TAKE SO LONG FOR ME TO BUILD ONE. AND IN ADDITION, THERE ARE NOT ADOBE HOUSES AROUND WHERE WE LIVE. IT MIGHT BE BECAUSE OF HEAVY RAIN IN WINTER. OLD HOUSES WERE MOSTLY CONSTRUCTED OF STONE AND SLIP STRAW IS USED AS A MORTAR.

Lina Joana wrote:Interesting project!
I am curious as to what you mean by passive, and how tight your comfort window is. A truly passive house that keeps the temperature at 25 c year round is tricky - witness the earthships that have gotten way too hot, etc. people do simple houses that way (as described in Mud Ball), but they are willing to put up with wider temperature fluctuations - so if you are comfortable with 16 C in the house on winter days, no problem. I am not an expert, but I think the things you need to look at are solar gain in summer vs winter, and air flow based on window positioning. You want sun in winter, shade in summer, and the ability to regulate air flow by opening and closing windows. Remember, insulation only keeps heat in if you are generating heat in the first place! Now, if you include a heating stove, that is different, of course. Apologies if you have thought all this out already!
18 DEGREES WOULD BE FINE WITH ME IN THE WINTER DURING THE DAY AND 15 IS GOOD ENOUGH WHEN I AM SLEEPING. I AGREE WITH YOU ABOUT SOLAR POSITIONING, VENTING, SHADE IN THE SUMMER. WHAT I WANT TO DO IS TO HAVE A THERMAL MASS INSIDE THE HOUSE AND, IF POSSIBLE, A STONE OUTER COVER THAT WOULD FIT ON A COTTAGE IN A VILLAGE. THERE WILL OF COURSE BE A WOOD STOVE IN THE COTTAGE FOR WHICH I WILL USE MY PRUNINGS.

For the insulation: if you expect moisture to reach the insulation, loose straw is probably worse than synthetic. Damp straw is an invitation to mould and bugs. Straw bale gets away with it because it is so tightly packed, and because the moisture doesn’t get far before drying back out. Have you looked at cordwood building techniques? They typically fill the area around the logs with sawdust, preferably pine, mixed 12:1 with hydrated lime. Even that small amount of lime is enough to discourage bugs and mold, and if it gets damp, it hardens rather than collapsing. Something to think about. Might even work with chopped straw, I am not sure.
THANK YOU ABOUT YOUR INFORMATION ON LOOSE STRAW. I HAVE BEEN INVESTIGATING TODAY AND FOUND OUT THAT CAVITY STONE WALLS WERE COMMON IN THE UK AND THEY HAD BEEN BUILT TO LET THE MOISTURE/WATER FALL DOWN INTO THE CAVITY AND DRAINED AWAY WITOUT TOUCHING THE INNER WALL. HOWEVER, I FOUND NO INSULATION METHOD THAT WOULD BE SUITABLE IN BETWEEN, BECAUSE THERE IS A DANGER THAT THE MOISTURE WILL GO IN AND DAMAGE AND LESSEN THE AFFECT OF THE INSULATION BECAUSE OF THE DRIVING RAINS HERE IN THE WINTER. THAT IS WHAT I READ ALMOST EVERYWHERE THAT HAPPENS IN THE UK WHERE THEY NEED TO BE SURE THAT THERE IS NO LEAKAGE IN IN ORDER TO INSTALL THE INSULATION.

Two stone walls sounds like a LOT of work. What about an outer wall a granite, an insulation cavity, and a pine interior? A lime plaster on the inside of the granite could help discourage moisture, and you could leave a south facing wall, or one that is protected from the wind, as the granite if you want that look inside the cottage. Just a thought, and I admit the closest I have come to building with stone is cinderblock, but it seems to take forever in my hands.
LIME PLASTER IS A GOOD IDEA AND I HAVE READ THAT THEY (TADELAKT) WORK REALLY GOOD WHEN THEY ARE DONE IN THE CORRECT WAY. THAT COULD BE A GOOD SOLUTION MAYBE ON THE INTERNAL SIDE OF THE EXTERIOR WALL. I WILL DISCUSS THIS WITH MY FRIEND WHO IS AN ARCHITECT.

Suleyman Koseoglu wrote:HI LINA!
THANK YOU FOR YOUR REPLY!
I AM NOT SURE HOW TO REPLY TO QUOTES. I AM DOING IT WITH CLICKING ON THE "QUOTE THIS QUOTE BUTTON" AND WRITE BACK IN CAPITOL LETTERS WITHIN THE ORIGINAL QUOTE. IF THERE IS ANY OTHER WAY. PLEASE LET ME KNOW.

Denis Wang wrote:Hi, sounds like a nice project.  I live in a 15' x 20' small house I built 4 years ago.  I'm wondering if you have building codes where you're going to build.  If you do, that may influence what you can do.  My house has 8 inch walls, double studded without thermal conduction between them and have worked great.  Perhaps you could do the same with a stone wall, vapor barrier, insulated thermal space, then interior wood-framed wall with insulation and surfacing. As mentioned, the type of insulation that can 'breathe' and/or resist mold and bugs is important.  Do you have sheep wool available in your area for insulation?  In a small tight house, moisture is the #1 consideration from cooking, bathing/showering, breathing moisture, indoor plants, etc.  Be sure to have good interior air flow and exchange all year round (especially in the winter) through windows or vents placed to utilize seasonal wind directions.  The challenge is during the winter when you want best interior heat retention plus adequate air exchange.  Of course there are mechanical/electric heat recapture solutions, but that might not be what you want.  A perfectly vented, interior wood stove could solve that problem.  I'd also recommend that a good 'hat' on a small house is paramount, so have enough dry insulation up there.  Through good insulation, I'm able to keep my house warm in the winter (using a green energy 300W infrared heat panel) and cool in the summer here in the Pacific Northwest, a bit cooler but similar to a med climate with wet winters and dry hot summers.  Best of luck!

Jennifer Davis wrote:Your climate sounds just like Texas, where I live.  Your soil does, too.

I've thought about using a double-wall method before also.  My idea was to ventilate inside the wall to cause moisture to dry up before it damages the insulation.  It would also help to cool things in summer.

Your window insulation ideas sound great.

Good floor ideas.  The standard way we build floors in Texas is to put the pipes down and then pour an uninsulated concrete slab over them.  The pipes won't freeze, and they do help to insulate the house.  However, if you ever leave your house empty in the winter and don't leave the heat on, the pipes could freeze.  It would be better if you had insulation in the floor.  I saw this person who used lava rock with earth over it as her floor.  She said the lava rock insulated the floor because it's porous and traps air inside of it.

Granite has been used as a building material for centuries.  I suppose it still could emit radon.  Maybe that's why they used to make ceilings much higher in old buildings.  From what I understand about radon, it won't be a problem as long as you can ventilate all the air out of your house on a regular basis--especially the air near the ceiling.

The rainwater storage tank placement sounds good.  I would use IBC totes for water storage because we can get cheap used ones around here.  I can get about 175 gallons of storage for $50.  If I try to buy new or used water tanks, they cost $1 per gallon.  Another idea I have is to build a sand cistern.  This would only be cost-effective if you have sandy soil on the property; otherwise, you're going to have to have a lot of sand hauled in.  If you have plants shading your pipes, they should be ok in the sun.  You really need to keep them shaded so the water doesn't get too hot.

Thomas Michael wrote:  I like Mike's idea of looking at earth ships you have a wetter and warmer climate than they are normally built in,  Also the wofati is a kind of modified earth ship, built in colder climes.  Building materials changed to granite / wood.  Look at the space designs, venting, water control etc. but use your locally available  materials.  

 In 9b and with your acceptance of a wider temp range in the house, you can look at full passive designs.  Since you have free rock you should look at a Trombe wall.  35cm  thick with 1 way vents top and bottom it should work well there.  This would be a very conventional looking cabin. You can improve the performance if you add a small porch.  The overhang sized to shade the Trombe wall in summer. In-closing the porch with glazing will help in the winter heating  but will need removal  for summer.  

Cooling can be aided with vents both high and low on the north wall.  In the summer leave them open at night.  Vents need to be the same size top and bottom.  In the winter sleep high (loft) in the summer sleep low.

East, west and north wall double wall.  In-fill with lava rock, perlite, 3cm gravel or just leave it as an air gap.  Ask local builders what has been done.  

Materials:  lava rock / pumice stone  for insulation.
In Europe I believe commercial roman lime mortar is available.  This has self healing properties.

Roof, regardless of earth berm walls, consider a living roof is not flammable.    

With stone walls you can always add earth berming later.  

Trombe wall.
https://www.sciencedirect.com/topics/engineering/trombe-wall
Tom.

roberta mccanse wrote:It seems to me that you would do well with an earthen roof. A waterproof film of some sort covered with a foot or more of dirt can be planted with native grasses, or whatever you want, provides good insulation, rain water catchment, and cooling in summer.

I live in and earth sheltered home and I garden on the roof. Of course my structure is concrete and rebar and I have three feet of dirt on top. It’s basically a cave so it’s cool in summer and easy to heat with wood in winter. My pipes never freeze.

Of course you don’t have to have an earth sheltered home in order to have an earthen roof. I have seen a restaurant in Wisconsin that has a roof of earth and grass where the roof rises at an angle from the ground. There were goats happily climbing up the roof and eating the grass. What a great multipurpose structure.

roberta mccanse wrote:The only water catchment system I have is a gutter at the bottom of an overhang I put outside my garage doors. The gutter directs water, snow melt, etc. to a rock lined ditch that waters a maple tree planted at the bottom. I considered gutters, and a rain barrel, on a narrow overhang that is over my directly south facing windows but I'm not sure how much water I would collect. In any case it hasn't happened yet. Ha.