Is a hexagonal house feasible?

Question

Recently I have been considering the economics and feasability of building a house versus buying a used one. In my design I settled on a hexagon as the logical shape for the frame, which I am considering for masonry construction. This would be a big house, each side being at least 30 feet wide (footprint 2340 sq ft). The advantages of a hexagon are obvious: simple roof shape, no valleys, space efficient, heat efficient (this would be in New England and subject to cold winters), good wind resistance.

What I can't understand is why there seems to be no-one building hexagonal houses? The only notable building I could find at all was the Supreme Court.

Possible explanations would be that the shape is expensive for small houses due to the 6 corners, but for a large house like mine the room shapes work out fine, in fact they are better than a box house. Maybe its just tradition? People don't like it because it looks like church? Builders have some objection to 60-degree angles?

What is the reason there are no hexagonal houses?

Answer 1

Building parts, building tools, building techniques, and building skills are all based on square walls. With building parts, you have things like bricks with 4 sides, wood sheathing with straight edges, not to mention studs, drywall, and most other building materials with factory edges. With tools, framing squares, levels, speed squares, and corner tools for drywall mud and paint, are all based on 90 degree angles.

However, the big reason to me are building techniques and skills. With 90 degree cuts, a top/bottom plate for framing the wall doesn't matter if it's upside down. You don't have to worry about which side of the framing the measurements are based on because it should be the same measurement. When checking that walls are aligned, builders use 3-4-5 triangles and measure the diagonals of a rectangle to ensure that they are square.

Finally, many homes are built on lots that often have parallel sides and homes are often built to maximize the utilization of these lots.

When building things that aren't square, there's also an increased risk for waste due to mistakes. Construct the framing with the 60 degree angle reversed and you'll likely have to throw out some of the framing. And for the exterior siding/finish, you'll end up with lots of cuts for bricks or custom corner pieces for siding. With the added materials and labor, this significantly increases the expense of building a home.

Answer 2

I live in an area with at least 3 or 4 N-gon (not necessarily octagon) houses. I've been inside one and, as a house geek, asked the owners plenty of questions.

Here's what I picked up:

• They love the house
• It is FAR larger than it looks from the outside. Like most houses in the neighborhood, this is in the 2000-2800 ft² range.
• Cabinetry wasn't a problem. The kitchen runs a large part of the diameter of the house, so isn't along the outer walls except for one side. (Side note: The kitchen is quite nice and the design works really well).
• Many were built, probably from the same contractor. We are in a low-population area, so if we have a contractor with such experience, you probably do, too.
• Because of the pseudo-curve of the roof, the view is particularly amazing in this house because the windows facing the valley view both out and up without interruption.

Downsides:

• Just last Saturday, I commented about how Re-roofing must be pretty interesting. Many of the shingles are bent over the diagonals joining each triangle. They hired a roofing company which did the work just fine, but it's better in the rear than the front where they started. So if you have a spherical roof built, be sure they start shingling in the back of the house.
• Looks small for the internal volume.
• Replacing the view windows I mentioned was done by the owner and required rope hanging form the top of the roof because there's no safe surface on which to to stand.

We live in an area which gets quite cold in the winter, but I have no information on their HVAC cost. I'd say it's MUCH more important to build your house using closed-cell spray-in foam insulation than it is to make the house any particular shape if the target is saving utility costs.

Here's a map of one of the houses: https://www.google.com/maps/preview/@42.8755102,-112.4149699,51m/data=!3m1!1e3

Answer 3

I agree with others... the amount of custom work required is going to obliterate your budget. Custom-cut flooring, custom-cut drywall, custom wood framing, custom kitchen. Everything will be a hand-done one-off. I wouldn't be surprised if the final cost were double what you'd pay for a square house of comparable footage, and take a lot longer to build.

If you're concerned about heat efficiency (and you should be, in New England), spend a fraction of that money on extra insulation and a high-efficiency furnace instead.

Edit

I don't mean to sound pessimistic about a hexagonal house. Sounds like a very cool idea, and if you're passionate about building an unusual house I'm sure you will find a builder willing to work with you. If a contractor laughs you off, tell them they just lost a big job.

Just don't have any disillusions about making a "more efficient" house. A hexagonal house is definitely going to cost more money and it will not pay for itself in energy savings. But that doesn't mean you shouldn't do it. Stainless steel appliances and granite counters don't pay for themselves either; people install them because they like them.

Answer 4

There are many reasons why you don't see many round homes (this includes octagon and hexagons).

Tradition

The majority of homes constructed in the United States starting with the colonial period were rectangular. The European settlers took designs from their homeland and replicated them here. From then on, especially on the east coast, many houses had a similar appearance.

Ease of Construction

It is much easier to plan out a rectangular building than a round one. Even with modern technology, these angles can be difficult to calculate and to cut. It would have been much more difficult to build these kind of buildings without the aid of power tools, CAD programs, etc.

Interior Design

Round homes are a challenge to plan the inside space. Rooms usually have odd shapes, and there are often strange little alcoves and wasted areas. Splitting up rooms is like trying to evenly fit a bunch of squares inside of a circle. It can be done, but it does take quite a bit more planning.

Efficiency

A round home isn't going to be much more or indeed any more efficient than a rectangular one as far as energy consumption. Any home that is properly insulated and has efficient HVAC will perform around the same.

Maintenance

As another user pointed out, some things will be more difficult to maintain such as the roof. Most roofers don't have a lot of experience with these buildings and there will be trial and error.

Answer 5

Wow: talk about "thinking inside the box". I've been building "oddly shaped" houses for years, and the Hexagon is by far the most efficient, acoustically sound and strongest structure to build. No; it doesn't have to cost a lot extra. The trick is to do the math ahead of time to make the most efficient use of dimensional (especially sheet goods) materials, or move away from the "2x4" mental prison and use native (rammed earth, block, adobe, straw bale, timber frame, etc) materials that aren't constrained by "conventional" (think: Industrial") production methods. There are specific sizes that make very good use of "lumber yard" materials. The trick is to keep track of off-cuts (especially metal roofing) to use in reverse elsewhere. Or make an Earth Roof (much better insulation and pretty). Run shingles long on the hips and cut at peak. A little planning and cabinets can easily be fit within. Talk about waste: the #1 source of landfill waste is conventional (box) construction!

Answer 6

IIRC, all of Frank Lloyd Wright's later houses were done on a 120° grid. If you want to know more about them, head down to your local architecture school and dig into their library; most architecture libraries will have books on Wright giving detailed to-scale drawings of his buildings.

Answer 7

Hawaii and other islands build these Octagonal shaped homes but I prefer metal frames so I moved on with the research. I am not a builder but it looks like this site which has sizes up to 70' : http://www.rcpshelters.com/SLF-OCT.php plus my favorite house plan: http://www.coolhouseplans.com/details.html?pid=chp-19987 could work with multi-unit. However, I am not far enough along to determine structural integrity and cost so take it as an idea.

Answer 8

For reference, there are two-story hexagonal apartment buildings in Waveland, Mississippi that share a common wall and are divided into quadrants in the interior.