Skip to content
Plot

Browse by place

Five counties have had their own code read — the rest answer from state law:

Appearance

Modular

Sections built in a factory to the same building code as site-built homes, then transported and craned onto a permanent foundation. Oregon operates a state approval program for factory-built structures.

At 1,500 sq ft
$165,000–$352,500
Timeline
4–7 months

What this figure rests on

No survey covers this method — pegged to one that does

No official survey separates modular from site-built construction. Trade research generally places modular ten to twenty percent below site-built for comparable quality, which against the Census West region median of $176.87 per square foot would imply roughly $140 to $160. The range kept here is wider in both directions because that relationship is a trade generalisation rather than a measurement.

Last verified August 16, 2026 · source

What it costs, broken down

  • Modular — base construction$120,000–$262,500

    Published ranges for this method generally represent a complete build, though not utility service to the parcel.

  • Site half of the cost$45,000–$90,000

    Quoted module prices typically cover only the factory-built portion, often around $50 to $100 per square foot. Foundation, delivery, crane set, utility connections, site work and general contractor overhead commonly add roughly $30 to $60 per square foot on top. On raw rural land this is the part that most often breaks a budget.

Advantages

  • Roughly ten to twenty percent below site-built for comparable quality, per industry research
  • Factory construction is unaffected by weather; timeline is roughly half
  • Treated as real property for financing and appraisal, unlike manufactured homes

Tradeoffs

  • Requires crane access and a road capable of carrying module transport
  • Design changes after the factory order are expensive or impossible
  • Fewer factories serving any given rural area

What building does to the tax base

Oregon generally limits growth in a property’s maximum assessed value to three percent per year, and treats new construction as an exception to that limit.

In general terms, holding unimproved land tends to mean a low tax base that grows slowly and predictably.

Adding a dwelling generally causes a step change in assessed value rather than a gradual increase, because the new structure is brought onto the roll at its own value rather than inheriting the capped figure.

Illustrative assessed value added: $82,500–$299,625

This range is illustrative only. It applies a wide assumed ratio to construction cost to show rough scale and direction, and is not a tax estimate. Actual assessed value depends on the county’s changed property ratio for the year and the assessor’s valuation, and the resulting tax also depends on the district’s permanent rate.

  • Ask the county Assessor how new construction would be brought onto the roll for this property.
  • Ask for the current changed property ratio and the applicable district tax rate.