This board was tremendously helpful to me in planning my new house so now that it’s done I wanted to report back on what I did and lessons learned. I wanted to build a house with a unique design in a location with somewhat unique conditions. First the climate and site basics: This house is a DIY project with very little subbed out. It is on an island off the Rhode Island coast, Climate Zone 5 in the book with a microclimate more like 4. Being an island fuel costs are high – with electricity hitting a peak of $0.68/kWh! Oil and propane are also high, no gas available. My six acre site does have a constant supply of black cherry. The micro climate is humid, very windy (140 mph design wind) and I used +5 as a design temperature. The site is high and well drained. There is a terrific view to the east, northeast and north. Durability is very important and the mainland standard for exterior finishes and flashings etc just won’t last here. So, my priorities were good, interesting design, capture the view, be energy efficient, build in durability, recycle some materials, and control mold and mildew (my spouse has severe allergies). I wanted to get 4 bedrooms and 2 ½ baths into about 1,900 square feet. I spent 2 years in the design stage went through hundreds of designs. I debated going for LEED or Passive certification and decided against it to avoid the arbitrary thresholds and point grubbing involved. So I came up with a house that is a series of five plain gable boxes, each proportionally smaller than the one before and attached by their gabled ends to progressively step down in size. The ridges run due east/west. The largest “box” is 25’ x 30’ and the smallest (the outside shower) is about 5’ x 8’. The roof is standing seam aluminum and the siding is painted cedar board and batten. Windows are Accurate Dorwin fiberglass windows (non impact resistant – structure designed as partially enclosed), doors are Andersen Patio doors. The full basement foundation is ICF (6”), first floor is bar joists and metal deck with 4” polished concrete slab (with radiant tubing). Exterior structural walls are 2x4 @16 with zip sheathing (walls contain steel portal frames and trusses for wind loading), second floor is TJI framing, subfloor with 1 ½” of gypcrete poured over radiant tubing. Roofs are 2x10 rafters, unvented cathedral ceilings. Here’s where it gets different…. To the interior side of the exterior walls I added horizontal 2x4’s on the flat screwed to the studs @16” to create a 7” cavity with minimal thermal bridges (sometimes called a Mooney wall). On the exterior of the Zip I added 2” of continuous XPS, commercial Tyvek, strapping and the board and batten rainscreen (with venting top and bottom). The 7” cavity was blown with cellulose. That works out to about an R38 wall. Roof is Zip sheathing over which is 4” of XPS and a layer of 5/8 CDX, Grace Ultra, Vapro Shield Slope Shield and metal roofing. So the roof is roughly R-58. The foundation ICF is about R23 and there is 4” of xps under the slab for R20. Air sealing was a huge priority everywhere. I hit 0.5ACH50. Windows work out to about R4 and the glazing was tuned to the various exposures – I decided to not go crazy with windows and chose durability of fiberglass over efficiency of triple pane. I have more south glass than north but also gave in to the view so there is a lot of east glass, too. There are only three 24x24 west windows. The heating is radiant hydronic throughout – fired by a Lochinvar propane boiler with indirect water heater off it. Cooking and dryer are propane. I have used approximately 240 gallons of propane from May 15 and February 8 (averaging 6.2 gallons per week) plus about ½ cord of wood. Every light in the house is an LED. I have a small, six panel 1.8 KV solar array on the roof. Ventilation is via two HRV’s – one upstairs, one down. No A/C. So how does it all work? Overall, really great!! The good – the house is solid and stiff and very comfortable to be in even at 10 degrees out and blowing 60 knots. The propane radiant keeps the inside temp nailed at 68 without fluctuating even a degree. The solar is great and most months meets my demand of +/- 200 kWh with lighting, well pump, fridge and chest freezer. The highly insulated basement may be the only basement on the island that doesn’t smell of mold! Passive solar is great – I spent many hours working out the shading and it works well – doesn’t overheat in summer and on a sunny 15 degree day the house will go up to 72 or 73 which feels great. There is so little heat load the radiant floors do not get noticeably warm but I expected that given the low heat loss. I like the polished concrete floors and second floor cork floors. We built a masonry chimney and have a Grand Godin wood/coal stove. An armload of wood each night makes the first floor pleasant and snug (I have a ton of coal in case of power failure – stove on coal heats whole house pretty well). The Mooney walls are nice and stiff and the dab of PL400 at each wood on wood crossing eliminated all squeaking. Now, lessons learned – actually not much I would change. I learned a lot about polished concrete and I think would get a better result if I were to do it again – but no regrets on that flooring choice. I did my own version of a heat loss calc figuring every square foot of exterior material and my heat loss came to about 25,000 Btu’s. Two propane service guys told me I needed a 250,000 boiler – they made me nervous enough so I went with an 80,000 boiler instead of 45,000 (the smallest). The boiler short cycles in spring and fall. I was concerned about the aesthetics of the roof mounted solar so I kept it small – I now wish I had gone to 2.4 or even 3.0 kW. Not having A/C is becoming an issue as we have several weeks a summer with hotter temps (75 maybe 80) but with 99% humidity. I’m researching some sort of dehumidification system – aesthetically there is no good place to put an outside condensing unit – spousal pressure to do A/C is mounting. I did place operable transoms over the bedroom doors and they work great for cross ventilation at night (idea stolen from the 1890’s seaside hotels out here). I installed 6 heating zones: basement, first floor, master BR and bath, BR & bath, BR & bath and BR. The smaller zones have a very small heat loss and are tiny compared to the boiler size. I might rethink that but being able to close off two bedrooms is nice. No surprise – I could use more closet space. I wish I had known to avoid XPS do to it’s GHG contribution. I used some recycled materials – beach stone shower floors, old school slate blackboard for backsplashes, old soapstone sinks turned into sinks and wood stove base, driftwood structural columns – but I would have liked to do more. I’m happy to answer any questions!

I'll post some pics when I get some internet access that can handle that......

Not trying to be a jerk. Your wall of text is a nasty side-effect with this forum on some web browsers.
This should make it more readable.

This board was tremendously helpful to me in planning my new house so now that it’s done I wanted to report back on what I did and lessons learned.

I wanted to build a house with a unique design in a location with somewhat unique conditions.

First the climate and site basics: This house is a DIY project with very little subbed out. It is on an island off the Rhode Island coast, Climate Zone 5 in the book with a microclimate more like 4.
Being an island fuel costs are high – with electricity hitting a peak of $0.68/kWh! Oil and propane are also high, no gas available.

My six acre site does have a constant supply of black cherry. The micro climate is humid, very windy (140 mph design wind) and I used +5 as a design temperature.
The site is high and well drained. There is a terrific view to the east, northeast and north.

Durability is very important and the mainland standard for exterior finishes and flashings etc just won’t last here.

So, my priorities were good, interesting design, capture the view, be energy efficient, build in durability, recycle some materials, and control mold and mildew (my spouse has severe allergies).


I wanted to get 4 bedrooms and 2 ½ baths into about 1,900 square feet. I spent 2 years in the design stage went through hundreds of designs.
I debated going for LEED or Passive certification and decided against it to avoid the arbitrary thresholds and point grubbing involved.

So I came up with a house that is a series of five plain gable boxes, each proportionally smaller than the one before and attached by their gabled ends to progressively step down in size.
The ridges run due east/west.
The largest “box” is 25’ x 30’ and the smallest (the outside shower) is about 5’ x 8’.
The roof is standing seam aluminum and the siding is painted cedar board and batten.

Windows are Accurate Dorwin fiberglass windows (non impact resistant – structure designed as partially enclosed), doors are Andersen Patio doors.

The full basement foundation is ICF (6”), first floor is bar joists and metal deck with 4” polished concrete slab (with radiant tubing).

Exterior structural walls are 2x4 @16 with zip sheathing (walls contain steel portal frames and trusses for wind loading), second floor is TJI framing, subfloor with 1 ½” of gypcrete poured over radiant tubing.

Roofs are 2x10 rafters, unvented cathedral ceilings. Here’s where it gets different….

To the interior side of the exterior walls I added horizontal 2x4’s on the flat screwed to the studs @16” to create a 7” cavity with minimal thermal bridges (sometimes called a Mooney wall).
On the exterior of the Zip I added 2” of continuous XPS, commercial Tyvek, strapping and the board and batten rainscreen (with venting top and bottom).
The 7” cavity was blown with cellulose.
That works out to about an R38 wall.

Roof is Zip sheathing over which is 4” of XPS and a layer of 5/8 CDX, Grace Ultra, Vapro Shield Slope Shield and metal roofing.
So the roof is roughly R-58.

The foundation ICF is about R23 and there is 4” of xps under the slab for R20.

Air sealing was a huge priority everywhere. I hit 0.5ACH50.

Windows work out to about R4 and the glazing was tuned to the various exposures – I decided to not go crazy with windows and chose durability of fiberglass over efficiency of triple pane.
I have more south glass than north but also gave in to the view so there is a lot of east glass, too. There are only three 24x24 west windows.

The heating is radiant hydronic throughout – fired by a Lochinvar propane boiler with indirect water heater off it.

Cooking and dryer are propane.

I have used approximately 240 gallons of propane from May 15 and February 8 (averaging 6.2 gallons per week) plus about ½ cord of wood.

Every light in the house is an LED.

I have a small, six panel 1.8 KV solar array on the roof.

Ventilation is via two HRV’s – one upstairs, one down. No A/C.

So how does it all work? Overall, really great!!

The good – the house is solid and stiff and very comfortable to be in even at 10 degrees out and blowing 60 knots.
The propane radiant keeps the inside temp nailed at 68 without fluctuating even a degree.
The solar is great and most months meets my demand of +/- 200 kWh with lighting, well pump, fridge and chest freezer.
The highly insulated basement may be the only basement on the island that doesn’t smell of mold!

Passive solar is great – I spent many hours working out the shading and it works well – doesn’t overheat in summer and on a sunny 15 degree day the house will go up to 72 or 73 which feels great.

There is so little heat load the radiant floors do not get noticeably warm but I expected that given the low heat loss.

I like the polished concrete floors and second floor cork floors.

We built a masonry chimney and have a Grand Godin wood/coal stove.
An armload of wood each night makes the first floor pleasant and snug (I have a ton of coal in case of power failure – stove on coal heats whole house pretty well).

The Mooney walls are nice and stiff and the dab of PL400 at each wood on wood crossing eliminated all squeaking.

Now, lessons learned – actually not much I would change.
I learned a lot about polished concrete and I think would get a better result if I were to do it again – but no regrets on that flooring choice.
I did my own version of a heat loss calc figuring every square foot of exterior material and my heat loss came to about 25,000 Btu’s.
Two propane service guys told me I needed a 250,000 boiler – they made me nervous enough so I went with an 80,000 boiler instead of 45,000 (the smallest).
The boiler short cycles in spring and fall.

I was concerned about the aesthetics of the roof mounted solar so I kept it small – I now wish I had gone to 2.4 or even 3.0 kW.
Not having A/C is becoming an issue as we have several weeks a summer with hotter temps (75 maybe 80) but with 99% humidity.
I’m researching some sort of dehumidification system – aesthetically there is no good place to put an outside condensing unit – spousal pressure to do A/C is mounting.
I did place operable transoms over the bedroom doors and they work great for cross ventilation at night (idea stolen from the 1890’s seaside hotels out here).

I installed 6 heating zones: basement, first floor, master BR and bath, BR & bath, BR & bath and BR.
The smaller zones have a very small heat loss and are tiny compared to the boiler size.
I might rethink that but being able to close off two bedrooms is nice.
No surprise – I could use more closet space.

I wish I had known to avoid XPS do to it’s GHG contribution.
I used some recycled materials – beach stone shower floors, old school slate blackboard for backsplashes, old soapstone sinks turned into sinks and wood stove base, driftwood structural columns – but I would have liked to do more.

I’m happy to answer any questions!

If AC is a minor issue of a couple degrees, you should be able to make do with strategic placement of a mini-split unit.
You will need to look into some form of dehumidification though.

Also, the nice thing about solar is that you can always add on to it.

And congrats on that 0.5 ACH50! You're in Passivehaus-land!

Also, New Shoreham?

Sorry for the wall of text - I'm on a Mac and in the past at least my browser wouldn't allow returns.

Yes. I'm on Block Island.

Looks like I can use return! Now I really feel dumb!

My solar uses micro inverters and clipping to standing seam makes racking easy so I will likely add on.

I the A/C almost all my load is latent and Ive seen over cooling cause other issues here. working on that one.

Yes. I'm on Block Island.

Looks like I can use return! Now I really feel dumb!

My solar uses micro inverters and clipping to standing seam makes racking easy so I will likely add on.

I the A/C almost all my load is latent and Ive seen over cooling cause other issues here. working on that one.

That's the thing, if you need AC, and can't get the home itself to self-regulate cooling in your comfort band, then a small mini-split, probably in your main living area, wild work fine.

And if you're that tight already, it's not as if the thing is going refrigerate you...