Author Topic: Passive solar shop build (Read 8488 times)

bigrockcandymountain · « **on:** August 20, 2020, 12:27:46 PM »

I thought I would share some pictures of the shop I am building. It is 32 x 48 with 14' high sidewalls. My house has R60 walls and I wouldn't change a thing. So the shop will have R60 walls 17" thick and 4 large south facing windows.

I am leaning toward dense blown cellulose for the walls, but it is really not easy to make happen here. The house is rock wool batts but the price has doubled on those so they aren't too competitive.

Mary B · « **Reply #1 on:** August 20, 2020, 03:37:46 PM »

wow! They did 8 inch thick walls on my new garage. Insulated slab. With no heat on it never drops below 28 in there all winter. and is very easy to get back up to 60 with a small propane heater.

bigrockcandymountain · « **Reply #2 on:** August 20, 2020, 05:01:00 PM »

That is good to hear. I am hoping to keep this around 10c 50f all winter with no active heat system or very little. It goes down to -40 the odd time here, but not for long. Usually nights are -20c in the middle of winter.

I figure I would rather spend the money that would go to a heat system on insulation. It should work out about even, but quite a bit more work.

SparWeb · « **Reply #3 on:** August 20, 2020, 09:25:29 PM »

Have you seen Gary's solar thermal collectors on https://builditsolar.com ?

It's one of his "homepage" projects even though the site seems to have thousands of DIY projects on it.
He's studied it in great detail so you can even size it for a certain amount of heat you will need.

bigrockcandymountain · « **Reply #4 on:** August 20, 2020, 09:56:47 PM »

Spar I'm glad you posted a link to that website. They have a heat loss calculator that I use all the time. I'll check out the collector design sometime but probably won't really need anything that complicated.

Another great tool is https://susdesign.com/windowheatgain/

It calculates the heat gain of south facing windows based on your location etc.

Mary B · « **Reply #5 on:** August 21, 2020, 03:33:50 PM »

Quote from: bigrockcandymountain on August 20, 2020, 05:01:00 PM

That is good to hear. I am hoping to keep this around 10c 50f all winter with no active heat system or very little. It goes down to -40 the odd time here, but not for long. Usually nights are -20c in the middle of winter.

I figure I would rather spend the money that would go to a heat system on insulation. It should work out about even, but quite a bit more work.

-28c is a typical Mid January temp overnight, can get a solid week of -17c high temps...

bigrockcandymountain · « **Reply #6 on:** August 21, 2020, 03:46:34 PM »

Wow mary, your making me wonder if this might be a touch overkill. Oh well, hopefully it is room temp all winter with no heat. I wouldn't mind that one bit.

SparWeb · « **Reply #7 on:** August 21, 2020, 09:38:45 PM »

Thank you, too BigRock.
That SHG calculator will be handy to me, too.
At my latitude (and yours too I assume) the SHG is actually strongest in spring and fall.
Intensity AND angle matter.

MattM · « **Reply #8 on:** August 26, 2020, 08:10:31 AM »

Rock wool is worth the price of admission in many ways. I'd want at least part of any exterior void with it for sound deadening.

bigrockcandymountain · « **Reply #9 on:** August 26, 2020, 09:39:26 AM »

I have been pondering back and forth again on mineral wool. As far as sound deadening, I think cellulose is close. They are both fantastic though. My house has 15" rock wool and one of the most frequent comments we get is how quiet it is.

They benefits of passive house are way more than just saving money on heating. My biggest observation living with this house has been peace of mind.

One morning was about -40 and the propane didn't want to flow. The house was still cozy and warm, so I just left it and didn't worry and soon the sun hit the tank and the problem fixed itself. A normal older house you would be pretty panicked to get the heat back on.

Another thing is the price of energy. So the price of propane goes to $20 a gallon. We can still work with that. In fact I advocate the price of energy should be higher. After all, people won't conserve something that is cheap.

Comfort is another thing. It's pretty hard to explain, but a house with no drafts, nice humidity and fresh air via an HRV is way more comfortable than one that is just warm from a furnace working over time.

So quiet, comfortable, and ready for any disaster are the 3 reasons to build a passive house that I preach to most people. Most people that build new houses don't really care about saving on energy bills in my experience.

Mary B · « **Reply #10 on:** August 26, 2020, 02:00:56 PM »

Sprayed in foam is the ultimate insulation. Zero drafts because it seals every crack...

DamonHD · « **Reply #11 on:** August 26, 2020, 02:48:16 PM »

Providing it (a) doesn't shrink and (b) doesn't crack and leak when the building flexes over time.

Plus some people aren't keen on the blowing agents or the fossil fuel source of the foam itself or the other volatiles.

Rgds

Damon

MattM · « **Reply #12 on:** August 26, 2020, 06:36:53 PM »

I've always wanted to try foamed cement products as an exterior insulation, but that's never been a good option where I've lived. Your byproduct from cement foaming is very mild to the environment.

You roll the dice with spray foam. A bad manufacturer batch can leave the house smelling like cat urine or worse. And a tight house is great but consider all spray foams offgas. You want it to go outside and not get trapped in the interior of the home.

Cellulose is second favorite attic fill but my least favorite wall insulation. It always sags. I prefer two layers of sheathing on the exterior of the house, with rock wool on the outside half of the stud spaces at a minimum. Even with 2x4 walls you're pretty quiet at this point and you're looking at an R19 overall score with insulated siding.

Rock wool is a nice firebreak, better than cellulose without the mess. Wrap the exterior of your home and tape to assure air tightness. Then go right ahead and cover with insulated siding if you like foam. Fewer seams on insulated siding and all your offgasing products on the exterior. I eliminate the older fan fold crap that is just a scam IMHO.

richhagen · « **Reply #13 on:** August 26, 2020, 11:52:36 PM »

Being in a big city I am very envious of all of that space. My solar collection is limited because of the size of my roof and lot here. Your shop is looking good, and I for one, am a bit jealous. Rich

bigrockcandymountain · « **Reply #14 on:** August 27, 2020, 11:04:59 AM »

I am not a fan of spray foam. It has its place with very irregular shapes(quonset etc) , but I would never consider it for a regular stud cavity. It is way too expensive for the r value, and all the people who have it that I know of are disappointed with it.
Air sealing is better accomplished with good attention to detail on a well defined air barrier.

Matt m, do you have experience with dense blown cellulose in walls? I have never tried it, but was wanting to use it for this shop. Research suggests it shouldn't settle at all if blown at 3.5lb per cu ft. I would really like to hear from some people that have good long term experience with it though.

To be clear, rock wool batts would be my first choice, if the price were the same for everything. I really do love working with it and think it does the best job.

MattM · « **Reply #15 on:** August 27, 2020, 08:38:16 PM »

I've torn out cellulose from walls never tried to dense pack it. Humidity shrinks it, so no matter how dense it is packed it will settle under its own weight. I've yet to see a wall cavity more than 60% full. I'm sure they all started full.

bigrockcandymountain · « **Reply #16 on:** August 27, 2020, 09:52:16 PM »

Wow 60% is really bad. Are you in a particularly humid place? We have really low humidity here most times, but still enough moisture at times to be a concern.

I still have not committed to cellulose. I have never even seen it in a wall. It is common in attics here but not walls.

MattM · « **Reply #17 on:** August 28, 2020, 12:03:02 AM »

I've spent most of my time in the Midwest and the last decade in Florida, so Yes & Yes.

bigrockcandymountain · « **Reply #18 on:** August 28, 2020, 08:59:25 AM »

Hmm you have me thinking Matt. We have a climate more like Arizona here.

I will get rock wool figured out by the bag and get a quote. Surely they can do a bit better. It will be over 100 bags.

We just started doing roof trusses yesterday.

Then it got too windy and we had to stop.

MattM · « **Reply #19 on:** August 29, 2020, 04:48:56 PM »

I'm having a hard time seeing your wall detail. If myy eyes are seeing corrrectly you extended the 2x4 studs out with OSB planks and tied on half studs on the planks to give your wall more volume. It looks like your double-plate spans both inner and outer walls. That's a lot of detail work.

SparWeb · « **Reply #20 on:** August 29, 2020, 05:02:57 PM »

It took a double-take for me, too.
The inner wall is on the concrete pad, at the edge somewhat like a normal stud-framed wall.
The outer wall overhangs the concrete. While I see a top header all the way around, there are many places where the outer wall does not come down to the level of the pad.
So in a way the outer wall is "suspended" and definitely not load-bearing.
For a sense of scale I can now see the entrance door on the latest photo, and I realize this will be very tall and impressive.
I'm also impressed that the bracing in the end-rafter is aligned with all the studs.
Since you aren't done the rafters yet, I'm a little confused by what I see there.
Will the next rafter go over the inner (load-bearing) wall? Or have I mixed something up?
Will you be attaching things to the roof such as a crane?

MattM · « **Reply #21 on:** August 29, 2020, 05:53:10 PM »

It almost looks like a lip for bringing up a brick or stone wall from down at ground level. I'm only guessing here.

The floor must be a foot thick.

bigrockcandymountain · « **Reply #22 on:** August 30, 2020, 09:10:34 AM »

Yes you guys are mostly seeing correctly. The outer wall being suspended is because it will be back filled up to that point. It will have rigid foam insulation 10" thick and then the inside wall of 2x6. That makes it flush with the stud wall above it.

It is on a pretty steep grade so about 5' backfill along the back wall. The inner wall is 2x6 and designed to take all the roof load and lateral soil pressure/ wind loads. It has proper headers over the windows etc.

The outer wall is connected to the inner with a web of osb glued and nailed with clinched nails. It forms a beam/ truss kind of. The outer wall is 2x4 studs and only there to space out the exterior so you can fit in a lot of insulation. No headers, single top plate etc.

The floor is a thickened edge slab so 12" thick at the edge but only 6" in the middle. It has floor heat pipes but I get the feeling I won't need them.

The next rafter will go over the inner load bearing wall. I don't have plans for anything suspended from the roof. I may build a rolling crane in the future that I can place anywhere.

bigrockcandymountain · « **Reply #23 on:** November 08, 2020, 10:29:56 AM »

Here we are doing the rigid foam yesterday. We got all done and backfilled.

This is this morning. I love snow so I really couldn't be happier.And the turbine has the batteries full so we can catch up on laundry today.

mbouwer · « **Reply #24 on:** November 08, 2020, 03:37:28 PM »

Beautiful landscape and nice ideas about building passive in this topic.

And I also think the turbine you built yourself is very special.

Greetings Rinus.

MattM · « **Reply #25 on:** November 08, 2020, 05:16:16 PM »

Are those R30 beaded foam, roofing insulation panels?

bigrockcandymountain · « **Reply #26 on:** November 08, 2020, 08:16:06 PM »

So it is 10" / r40 of type 1 eps for the vertical wall insulation. The horizontal insulation is 6" thick /r24 30 psi hard eps foam. Both were bought well below retail off kijiji (like craigslist). Some was used, some was new.

Bruce S · « **Reply #27 on:** November 09, 2020, 08:56:31 AM »

That snow sure looks like fun!!

Will you be using some sort of fan to move the warmer air from ceiling to body height?

Great timing
Bruce S

bigrockcandymountain · « **Reply #28 on:** November 09, 2020, 05:44:07 PM »

Yes tons of fun. Today was mostly digging out. Tomorrow hopefully some tobogganing.

I hadn't thought of a fan but i will use one if needed.
Before shovelling

After shovelling
[ Specified attachment is not available ]

SparWeb · « **Reply #29 on:** November 09, 2020, 11:15:49 PM »

My skis are waxed already - but I didn't get nearly as much snow as you did.

kitestrings · « **Reply #30 on:** November 15, 2020, 04:56:32 PM »

The building looks great, but wow, you got winter handed to you early, huh? We got one storm with maybe 4-5" of snow, but then an unusually warm spell that lasted nearly a week; and hit almost 70 degF It was quite welcome.

What's you're elevation? ~ks

bigrockcandymountain · « **Reply #31 on:** November 15, 2020, 05:04:11 PM »

We are 2500' here. This is the most snow any of the old guys have ever seen. Everyone estimates about 2' on the level of pretty heavy snow. It is looking like it will shrink a bit in the next few days above freezing.

I was just out at the shop a bit today. I shovelled the bank out of the door opening and located my pile of tin out back. I didn't quite get it extracted yet. I would like to build the doors and get it closed up, but have a lot of more pressing matters. We also have a baby due any day now, so that will slow the projects for awhile too.

Did you get your turbine back running ks? Or are you doing ok without it?

SparWeb · « **Reply #32 on:** November 15, 2020, 10:41:25 PM »

Quote

We also have a baby due any day now

Wait - What?!?

CONGRATULATIONS!

News:

Author Topic: Passive solar shop build (Read 8488 times)