Monolithic Dome House (Round House)

[Ariba]

Looking for suggestions on how to approach appraising this 2-Story Monolithic Dome House. Nothing similar sold in the market over the past 4-years. How would you even measure something like this?

 

[gregb]

Circle
Solve for
area




A = π r2

 

[George Hatch]

You do it by looking for atypical designs of all types that have ever sold anywhere in that metro area, and then comparing them to the sales of the conventional designs which sold during the same time frame. If the subject itself has ever previously sold then it's own prior sale will demonstrate how the market has already previously reacted to that design.

You're looking for the adjustment factor you're going to apply. Not necessarily for direct comps to put into a Sales Comparison grid. The same as if you had excess land but no recent sales with the similar lot coverage ratio. You build the adjustment factor first, and then import it into your comparison.

 

[Meandering]

We have them here.

In a jam, if you can't find any other dome sales, they can be compared to other "non-conventional" building styles,

You'll need to explain how the market perceives the design, being "non-conventional" because it will impact "marketability in the minds of the mindless box checkers.

A frames, if you can find them large enough,

Or other homes mis-shapen with odd additions that alter the original conventional design.

Narrate how or why the comps fit the more conventional designs or not, and move along with adjusting or not, depending on the data.

 

[Terrel L. Shields]

Log home, geodesic home, bermed home, etc. Proxies for "unique" property.

 

[Renee Healion]

Seems simple enough, π r²
But here is a dome guy's calculator for more shapes and all sorts of questions: https://www.monolithic.org/calculators/dome-calculator

 

[George Hatch]

If we're measuring and diagramming the structure then the software will calculate the area automatically.

With the structure in the pic you start with the diameter of the circle and either add or subtract the cutouts. You don't have to get all those angles all at once. The CAD software doesn't care if you treat each cutout as its own area.

I just inspected this structure last week. I drew the lower level up in 5 different sections and moved them into place.

 

[gregb]

http://www.apexwin.com/main/downloads/supportdocs/Apex%20Sketch%20v7-Drawing%20Curves.pdf

 

[CANative]

Ask the owner (during the interview before scheduling) if they have the building plans.

GH's advice is spot on but may be hard to follow if you have not measured a lot of irregular buildings. There's a learning curve in sketching programs. Apex is probably the best. I assume he means "cut outs" to be areas that have negative GLA which will subtract from the overall GLA.

Apex also has a drawing function that allows one to easily draw polygons and circles and then convert them to whatever building area you need (GLA, barn, deck, etc.)

Find the widest point of the circle, from the inside if you can (might have to take several measurements due to interior walls.) That measurement can then be used to get the circumference. Draw a circle with that circumference and let it calculate as GLA. Do the same for the upper level if it is also a circle. If the upper level is not a circle and has "open to below" space, just do the best you can. Like measuring an odd ball condo.

IMO, it doesn't have to be exact and I don't think there are enough sales of similar to demonstrate a market reaction to small variances in living area. Just disclose and provide some explanation as to the rationale.

 

[CANative]

A geo-house I did when I was just starting off.