diff --git a/LICENSE b/LICENSE
index 781b8cd..815defb 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 BSD 3-Clause License
 
-Copyright (c) 2022-2025, Denis Bourgeois
+Copyright (c) 2022-2026, Denis Bourgeois
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
diff --git a/lib/osut.rb b/lib/osut.rb
index 7561fec..b0ede77 100644
--- a/lib/osut.rb
+++ b/lib/osut.rb
@@ -1,6 +1,6 @@
 # BSD 3-Clause License
 #
-# Copyright (c) 2022-2025, Denis Bourgeois
+# Copyright (c) 2022-2026, Denis Bourgeois
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
diff --git a/lib/osut/utils.rb b/lib/osut/utils.rb
index 77d8014..09bb951 100644
--- a/lib/osut/utils.rb
+++ b/lib/osut/utils.rb
@@ -1,6 +1,6 @@
 # BSD 3-Clause License
 #
-# Copyright (c) 2022-2025, Denis Bourgeois
+# Copyright (c) 2022-2026, Denis Bourgeois
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -530,7 +530,7 @@ def resetUo(lc = nil, film = nil, index = nil, uo = nil, uniq = false)
       mt.setName(id)
 
       unless mt.setThermalResistance(r)
-        return invalid("Failed #{id}: RSi#{de_r.round(2)}", mth)
+        return invalid("Failed #{id}: RSi#{r.round(2)}", mth)
       end
 
       lc.setLayer(index, mt)
@@ -546,7 +546,7 @@ def resetUo(lc = nil, film = nil, index = nil, uo = nil, uniq = false)
       k = (m.thickness / (r + dR)).clamp(KMIN, KMAX)
       d = (k * (r + dR)).clamp(DMIN, DMAX)
       r  = d / k
-      id = "OSUT:K#{format('%4.3f', k)}:#{format('%03d', d*1000)[-3..-1]}"
+      id = "OSut:K#{format('%4.3f', k)}:#{format('%03d', d*1000)[-3..-1]}"
       mt = lc.model.getStandardOpaqueMaterialByName(id)
 
       # Existing material?
@@ -928,7 +928,6 @@ def genConstruction(model = nil, specs = {})
     if u and a[:glazing].empty?
       ro = 1 / u - film
 
-
       if ro > RMIN
         if specs[:type] == :door # 1x layer, adjust conductivity
           layer = c.getLayer(0).to_StandardOpaqueMaterial
@@ -944,27 +943,7 @@ def genConstruction(model = nil, specs = {})
           return invalid("#{id} construction", mth, 0) if lyr[:r    ].to_i.zero?
 
           index = lyr[:index]
-          layer = c.getLayer(index).to_StandardOpaqueMaterial
-          return invalid("#{id} material @#{index}", mth, 0) if layer.empty?
-
-          layer = layer.get
-
-          k = (layer.thickness / (ro - rsi(c) + lyr[:r])).clamp(KMIN, KMAX)
-          d = (k * (ro - rsi(c) + lyr[:r])).clamp(DMIN, DMAX)
-
-          nom  = "OSut:"
-          nom += layer.nameString.gsub(/[^a-z]/i, "").gsub("OSut", "")
-          nom += ":K#{format('%4.3f', k)}:#{format('%03d', d*1000)[-3..-1]}"
-
-          lyr = model.getStandardOpaqueMaterialByName(nom)
-
-          if lyr.empty?
-            layer.setName(nom)
-            layer.setConductivity(k)
-            layer.setThickness(d)
-          else
-            c.setLayer(index, lyr.get)
-          end
+          resetUo(c, film, index, u)
         end
       end
     end
diff --git a/lib/osut/version.rb b/lib/osut/version.rb
index eb36a41..2c1149c 100644
--- a/lib/osut/version.rb
+++ b/lib/osut/version.rb
@@ -1,6 +1,6 @@
 # BSD 3-Clause License
 #
-# Copyright (c) 2022-2025, Denis Bourgeois
+# Copyright (c) 2022-2026, Denis Bourgeois
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -29,5 +29,5 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 module OSut
-  VERSION = "0.8.0".freeze
+  VERSION = "0.8.1".freeze
 end
diff --git a/spec/osut_tests_spec.rb b/spec/osut_tests_spec.rb
index df34b9e..8d4a243 100644
--- a/spec/osut_tests_spec.rb
+++ b/spec/osut_tests_spec.rb
@@ -154,6 +154,7 @@
     expect(u).to be_within(TOL).of(uo2)
 
     # Insulated, unfinished outdoor-facing plenum roof (polyiso above 4" slab).
+    model   = OpenStudio::Model::Model.new
     specs   = {type: :roof, uo: uo2, frame: :medium, finish: :medium}
     surface = cls1.genConstruction(model, specs)
     expect(surface).to_not be_nil
@@ -161,10 +162,11 @@
     expect(surface.layers.size).to eq(3)
     u = 1 / cls1.rsi(surface, film[:roof])
     expect(u).to be_within(TOL).of(uo2)
-    expect(surface.layers[1].nameString).to eq("OSut:polyiso:K0.023:100")
+    expect(surface.layers[1].nameString).to eq("OSut:K0.023:100")
     expect(surface.layers[2].nameString).to eq("OSut:concrete:100")
 
     # Roof above conditioned parking garage (polyiso under 8" slab).
+    model   = OpenStudio::Model::Model.new
     specs   = {type: :roof, uo: uo2, clad: :heavy, frame: :medium, finish: :none}
     surface = cls1.genConstruction(model, specs)
     expect(surface).to_not be_nil
@@ -173,9 +175,10 @@
     u = 1 / cls1.rsi(surface, film[:roof])
     expect(u).to be_within(TOL).of(uo2)
     expect(surface.layers[0].nameString).to eq("OSut:concrete:200")
-    expect(surface.layers[1].nameString).to eq("OSut:polyiso:K0.023:100")
+    expect(surface.layers[1].nameString).to eq("OSut:K0.023:100")
 
     # Uninsulated plenum ceiling tiles (alternative :shading).
+    model   = OpenStudio::Model::Model.new
     specs   = {type: :roof, uo: nil, clad: :none, finish: :none}
     surface = cls1.genConstruction(model, specs)
     expect(surface).to_not be_nil
@@ -185,6 +188,7 @@
     expect(u).to be_within(TOL).of(uo6)
 
     # Unfinished, insulated, framed attic floor (blown cellulose).
+    model   = OpenStudio::Model::Model.new
     specs   = {type: :floor, uo: uo2, frame: :heavy, finish: :none}
     surface = cls1.genConstruction(model, specs)
     expect(surface).to_not be_nil
@@ -192,9 +196,10 @@
     expect(surface.layers.size).to eq(2)
     u = 1 / cls1.rsi(surface, film[:floor])
     expect(u).to be_within(TOL).of(uo2)
-    expect(surface.layers[1].nameString).to eq("OSut:cellulose:K0.023:100")
+    expect(surface.layers[1].nameString).to eq("OSut:K0.023:100")
 
     # Finished, insulated exposed floor (e.g. wood-framed, residential).
+    model   = OpenStudio::Model::Model.new
     specs   = {type: :floor, uo: uo2}
     surface = cls1.genConstruction(model, specs)
     expect(surface).to_not be_nil
@@ -202,9 +207,10 @@
     expect(surface.layers.size).to eq(3)
     u = 1 / cls1.rsi(surface, film[:floor])
     expect(u).to be_within(TOL).of(uo2)
-    expect(surface.layers[1].nameString).to eq("OSut:mineral:K0.024:100")
+    expect(surface.layers[1].nameString).to eq("OSut:K0.024:100")
 
     # Finished, insulated exposed floor (e.g. 4" slab, steel web joists).
+    model   = OpenStudio::Model::Model.new
     specs   = {type: :floor, uo: uo2, finish: :medium}
     surface = cls1.genConstruction(model, specs)
     expect(surface).to_not be_nil
@@ -212,10 +218,11 @@
     expect(surface.layers.size).to eq(3)
     u = 1 / cls1.rsi(surface, film[:floor])
     expect(u).to be_within(TOL).of(uo2)
-    expect(surface.layers[1].nameString).to eq("OSut:mineral:K0.023:100")
+    expect(surface.layers[1].nameString).to eq("OSut:K0.023:100")
     expect(surface.layers[2].nameString).to eq("OSut:concrete:100")
 
     # Uninsulated slab-on-grade.
+    model   = OpenStudio::Model::Model.new
     specs   = {type: :slab, frame: :none, finish: :none}
     surface = cls1::genConstruction(model, specs)
     expect(surface).to_not be_nil
@@ -225,6 +232,7 @@
     expect(surface.layers[1].nameString).to eq("OSut:concrete:100")
 
     # Insulated slab-on-grade.
+    model   = OpenStudio::Model::Model.new
     specs   = {type: :slab, uo: uo2, finish: :none}
     surface = cls1::genConstruction(model, specs)
     expect(surface).to_not be_nil
@@ -233,7 +241,7 @@
     u = 1 / cls1::rsi(surface, film[:slab])
     expect(u).to be_within(TOL).of(uo2)
     expect(surface.layers[0].nameString).to eq("OSut:sand:100")
-    expect(surface.layers[1].nameString).to eq("OSut:polyiso:K0.010:043")
+    expect(surface.layers[1].nameString).to eq("OSut:K0.010:043")
     expect(surface.layers[2].nameString).to eq("OSut:concrete:100")
 
     # 8" uninsulated basement wall.
@@ -247,6 +255,7 @@
     expect(u).to be_within(TOL).of(uo7)
 
     # 8" interior-insulated, finished basement wall.
+    model   = OpenStudio::Model::Model.new
     specs   = {type: :basement, uo: 2 * uo2, clad: :none}
     surface = cls1::genConstruction(model, specs)
     expect(surface).to_not be_nil
@@ -255,7 +264,7 @@
     u = 1 / cls1::rsi(surface, film[:basement])
     expect(u).to be_within(TOL).of(2 * uo2)
     expect(surface.layers[0].nameString).to eq("OSut:concrete:200")
-    expect(surface.layers[1].nameString).to eq("OSut:mineral:K0.037:075")
+    expect(surface.layers[1].nameString).to eq("OSut:K0.037:075")
     expect(surface.layers[2].nameString).to eq("OSut:drywall:015")
 
     # Standard, insulated steel door (default Uo = 1.8 W/K•m).
@@ -291,7 +300,7 @@
     u = 1 / cls1::rsi(surface)
     expect(u).to be_within(TOL).of(uo9)
 
-    # Invalid Uo (here, skylights and windows inherit default Uo values)
+    # Invalid Uo (here, skylights and windows inherit default Uo values).
     specs   = {type: :skylight, uo: nil}
     surface = cls1::genConstruction(model, specs)
     expect(surface).to be_a(OpenStudio::Model::LayeredConstruction)
@@ -299,7 +308,7 @@
     u = 1 / cls1::rsi(surface)
     expect(u).to be_within(TOL).of(uo[:skylight])
 
-    # Invalid Uo (here, Uo-adjustments are ignored altogether)
+    # Invalid Uo (here, Uo-adjustments are ignored altogether).
     specs   = {type: :wall, uo: nil}
     surface = cls1::genConstruction(model, specs)
     expect(surface).to be_a(OpenStudio::Model::LayeredConstruction)