A better-informed
way to build.

Use the prescriptive values when that is the project’s approved compliance method and no specific exception applies. New conditioned construction and additions generally need energy-code compliance. An accepted total-UA or performance design may use different component values; it needs the required calculations and approval, not just a contractor’s opinion. Compare the three approaches.

Michigan: use Michigan’s amended requirements and accepted compliance documentation. The residential code also provides a separate Energy Rating Index route. Michigan energy provisions, N1105–N1106.

Wisconsin: SPS 322 provides prescriptive, total-UA, and simulated-performance options for covered one- and two-family dwellings. Requirements still apply unless that method specifically exempts them. SPS 322.02, 322.31 and 322.50–53.

Michigan: an alteration generally brings the work being changed into compliance without requiring untouched portions of the house to meet new-construction standards. Specific exceptions include existing exposed ceiling, wall, or floor cavities filled with insulation, and work where existing cavities remain unexposed, provided building energy use is not increased. These are alteration exceptions—not permission to underinsulate a new addition. N1101.3.1 and its exceptions.

Wisconsin: additions and alterations to covered dwellings follow the code applicable to the project; true repairs and maintenance have a separate exemption. Building age and local adoption matter. Chapter 322 energy rules began December 1, 1978; other UDC chapters began June 1, 1980. Older dwellings may be exempt under the state UDC, while municipalities may adopt its requirements for their additions and alterations. “Pre-1980” alone is not a reliable answer. SPS 320.03–320.05.

Describe what will be opened, replaced, or newly enclosed when you request the permit review. An attic top-up, a stripped wall, and a converted garage can have different obligations.

Michigan: converting an unconditioned or low-energy space to conditioned space triggers the residential energy code’s change-in-conditioning requirements. Review the enclosure around the converted space, not just the surface receiving new insulation. An accepted performance route may provide flexibility. Do not assume the ordinary existing-cavity exception settles a garage, attic, or workshop conversion. DOE/PNNL explanation of the 2015 conversion provisions.

Wisconsin: a barn or garage converted to residential use must comply with the UDC. Installing heating or air conditioning in a covered dwelling also invokes Chapter 322. A limited exception exists for supplemental heat in an attached garage: a permanently limited thermostat of 50°F or less, a separate heating zone or equipment, and any separate equipment sized for no more than 50°F. This is not a general exemption for heated shops or living space. SPS 320.04 · SPS 322.30(4).

Tell us the intended temperature and use before selecting insulation. Air sealing, ventilation, moisture control, and fire protection belong in the conversion plan too.

Michigan: yes. The residential update remains stayed; LARA lists the 2015 residential framework and the separate 2021 commercial energy code, effective April 22, 2025. Also, building-code and energy-code labels do not always match: some low-rise multifamily buildings use residential energy provisions while their construction is under the Michigan Building Code. Confirm occupancy and energy-code scope before using a house insulation table. LARA code list · Michigan residential-energy scope and paths.

Wisconsin: one- and two-family dwellings use the UDC framework. Commercial buildings and larger multifamily projects need separate review under SPS 361–366 and the applicable adopted energy provisions. The updated commercial codes took effect September 1, 2025, with compliance required for plans submitted on or after November 1, 2025. Do not apply the one- and two-family table to every building that contains residences. DSPS commercial-building guidance.

For existing commercial buildings, alteration rules generally focus on the work changed; new envelope assemblies and changes in use can trigger additional requirements. 2021 IECC C503–C505.

No automatic exemption. The actual use of the building matters. Agricultural zoning and post-frame construction do not establish an exemption by themselves.

Michigan: the statutory exclusion concerns a building incidental to agricultural use of the land, provided it is not used in retail trade. A house or unrelated business on farm-zoned land does not become exempt just because of the parcel’s zoning. MCL 125.1502a(1)(g).

Wisconsin: the UDC farm-building exemption requires exclusive farm operations and no human habitation. The commercial exemption also has specific farm-premises and farming-use conditions, including limits on consumer access and farm-product sales. Retail, an event venue, a residence, or mixed use requires a fresh review. SPS 320.05(6) · DSPS farm-building explanation.

Have the building department confirm the exemption for the intended use. Zoning, electrical, plumbing, mechanical, and other applicable requirements still need their own review.

No. Condensation-control insulation and total energy-code insulation are different checks. The 2015 IRC table lists R-25 for zone 6 and R-30 for zone 7 in applicable unvented assemblies; those values do not replace total insulation requirements. Ventilation, vapor control, and the assembly’s layers still need review. IRC R806.5.

No. The studs interrupt that layer. Continuous insulation crosses the framing. The material name does not change that distinction.

Not by itself. Insulation and air sealing do different jobs. Attic penetrations, hatches, and transitions need attention along with insulation coverage. DOE attic air-sealing guide.

A ground membrane addresses ground vapor. Drainage, leaks, groundwater, humidity, and the location of the thermal boundary still need to be evaluated. A liner-only price is not a complete moisture-remediation design. DOE/PNNL foundation guidance.

The answer depends on the space, access and use, product, and tested assembly. Thermal barriers and ignition barriers have different roles. A product’s fire test is not blanket permission to leave foam exposed; the final scope must identify the required protection. Manufacturer technical documents.

No. It prices the dimensions and material level you choose. It cannot determine the approved compliance path, inspect a roof assembly, or confirm local requirements. We review those details before setting the final scope.

There is no honest universal percentage. Existing insulation, leakage, heating equipment, weather, and how you use the building all affect the outcome. Jesse is a BPI energy auditor and building analyst. Our energy audits and blower door testing can help you understand the building and prioritize improvements. DOE guide to home-energy assessments (PDF).

Send the project town, approximate dimensions, a wide view, close-ups of framing or obstructions, and the access point. Roof pitch, cavity depth, crawlspace height, piers, and known moisture issues are especially helpful. Measure only areas you can reach safely.

For a flat, vented attic, we often start with cellulose for value and coverage. Fiberglass can be preferable where ceiling weight or an approved cavity installation favors it. Closed-cell foam offers compact insulation and air control at a higher cost. Our attic material guide explains settling, weight, slopes, and air barriers.

We plan the installation using the selected product’s initial thickness and required material quantity, with its settled depth already accounted for. The goal is the labeled long-term R-value. See how settling is included.