We’re building with concrete, for a number of reasons. It is strong, it can survive hurricanes and tornadoes, it is thick, giving us the wall thickness we desire, but also it is incredibly energy efficient, and I wanted to build an energy efficient castle.

Concrete has immense thermal mass which allows it to only slowly transfer heat. It actually works very well for a home since it takes so long for the walls to warm up and transfer heat, it takes all day, then they give the heat back during the night. Concrete walls are pretty much more energy efficient than any other wall type.

But we’re not even using regular old concrete, we plan to use ICFs, which are insulated concrete forms. Normally when forming a concrete wall wooden forms are put up and the concrete is poured in, it hardens, and the forms are removed. With ICFs the forms are premade with foam, the concrete is poured in, but the forms are then left in place.  This gives you a moisture/insulating layer of foam, then concrete, then more foam. In our castle it’ll be an inch of stone, half inch of mortar, 2 inches of foam, 6 inches of concrete, two more inches of foam, half inch of mortar, and another inch of stone, making for a fairly thick wall, and incredibly energy efficient.  Essentially it makes the whole house a double walled cooler.

For heat we plan to use a geothermal heat pump with radiant in floor heating on the first floor, which should be enough to heat the entire building as the heat rises. Our location is too remote for gas and geothermal is the most efficient electrical powered heating form I know. You essentially use the heat of the earth, which is a constant 55 degrees, running through various heat exchangers to heat or cool your house seasonally, the one system can do both (though, ducts will be required for cooling).  As far as energy uses go, it is very efficient, the most efficient heating method I know other than passive solar.

As far as cooling goes, I hope we don’t need much, by limiting windows, and having high ceilings, I think it’ll stay quite cool on the inside. When I visited Rome it was sweltering outside, yet stepping in St. Peters Basilica or the Parthenon it was always cooler, even though windows and doors were open, just being inside a large stone structure made it cooler.

Also our main skylight, which runs the center of the house, will be operable, allowing hot air to escape automatically in the summer in what is known as a solar chimney.  The skylight also provides ample natural light hopefully limiting the need for lights during the day in a house with this few windows.

The roof, being largely flat and hidden from prying eyes by the battlements, becomes an excellent place for a solar array, as pictured. I want to cram as many panels as possible on to the roof, as budget and space allows. In my ideal world we’ll be a net 0 (no net energy use) castle, but we’ll see how things turn out.

I have thought for some time, because of the height, that rooftop mounted wind might work as well, but as near as I can tell that technology just doesn’t seem to work well. Buildings can’t support turbines of any appreciable size because of vibrations and wind load and all these other things. We can leave the option open for the future.

We hope to heat the pool as much as possible through solar thermal heat as well. Much of the surrounding land will be used for home food production, which doesn’t necessarily make the building more energy efficient, but our lives will be.

I am not building a time capsule. It is not my desire to recreate a castle as it existed back in 1350. I am aiming for a more evolutionary structure. Conceptually with the idea that the castle may have been originally built many hundreds of years ago, and the bones of the structure would be that old, but that it would have been lived in since, and the interiors would have evolved with the ages. So the exterior would like old, but the interior might have very old beams and raw stone married with Victorian era woodwork styles, I don’t have a problem with that.

I am however of course making some sacrifices on the interior in order to both make it more livable and to better achieve the look I want on the exterior. Namely instead of doing relatively smaller interior rooms, I am doing large open floor plans, and I’m putting in a massive skylight. In my post on What Makes a Castle a Castle, which you should read before this post if you’ve not. I talk about how you need to minimize windows, especially at lower levels (and the “face” or front of the building) in order to look like a defensible structure (ie, castle). I’m doing that, heavily minimizing windows, but I don’t want to spend the rest of my life living in a dark and dreary place.

So I am using an open floor plan on the lower floors with minimal room dividers to allow what windows there are to light multiple rooms, and I am putting a large skylight over the center core of the castle, which will be open for three straight stories shining on the main staircase. The thing is like at least 12×25, I think bigger even. This feature is very uncastle-like, or at least I’ve never seen it, but it is the only way I think I can minimize windows to the extent that I want to.

I will also be using a splayed base as I discussed in my What Makes a Castle a Castle post, as well as very substantial battlements.

The other thing you can do is go tall, and get any windows as high off the ground as possible. I’m having the 1st floor start 6 feet off grade. The basement will have no windows of course. So you’ll ascend steps to enter the home from the front door (like so many churches). The floor structure is two feet, then if we say the first window is 4 feet off the floor, you essentially, on the exterior, don’t have a window start until 12 feet up (and even then I’m keeping them small). In the great room, which is two stories (the first floor will be 12 foot ceilings, others 10 foot ceilings), I’m putting in very large gothic windows with buttresses between them, but they’re not going to start until 8 to 10 feet off the floor (on a 24 foot ceiling height), so while they’ll be large windows, on the exterior they’ll still be 16+ feet off the ground. And they’re on one of the back sides of the house, facing state forest, not the public side of the house.

And yes, we’re are going tall. Our footprint, not counting the towers, is just a 40×60 keep. This section will be three stories tall. 6 feet off grade, plus two feet for the floor, plus 12 feet for the first floor, two more feet for the floor, 10 feet for the second floor, two more feet for the floor, 10 feet for the third floor, two feet for the roof, 6 feet for the battlements. The wall height of this section should be 50 feet.

We’re doing a four tower structure, the two front towers will be slightly smaller and have 4 stories with conical roofs, the back towers will be 5 stores with crenelated roofs, maximum wall height off grade including the battlements is going to be around 74 feet.

We are going tall both because it looks more like a castle, and once you get up high you’re allowed more windows (in fact, the tops of the towers will be all windows, as they should be. Once you get that high a tower without windows for full range of view isn’t fulfilling the purpose of a tower). But also to maximize our view. We’re on the summit of a ridge, but it is wooded. If we clear the immediate area of the summit our goal is to have the building high enough that we get the view above the trees lower on down.

Of course, going this tall necessitated us finding land not covered by a homeowners association, which was difficult, but ultimately we found the perfect lot.