diff --git a/src/EnergyPlus/DataHeatBalance.cc b/src/EnergyPlus/DataHeatBalance.cc
index 3a9d427acc4..719a610c8b3 100644
--- a/src/EnergyPlus/DataHeatBalance.cc
+++ b/src/EnergyPlus/DataHeatBalance.cc
@@ -906,6 +906,7 @@ int AssignReverseConstructionNumber(EnergyPlusData &state,
         }
         if (Found) {
             NewConstrNum = Loop;
+            state.dataConstruction->Construct(Loop).IsUsed = true;
             break;
         }
     }
diff --git a/tst/EnergyPlus/unit/DataHeatBalance.unit.cc b/tst/EnergyPlus/unit/DataHeatBalance.unit.cc
index 62e079f2619..8cf2ebeadd8 100644
--- a/tst/EnergyPlus/unit/DataHeatBalance.unit.cc
+++ b/tst/EnergyPlus/unit/DataHeatBalance.unit.cc
@@ -991,3 +991,50 @@ TEST_F(EnergyPlusFixture, DataHeatBalance_setNodeSourceAndUserTemp)
     EXPECT_EQ(expectedNodeNumberAtSource, thisConstruct.NodeSource);
     EXPECT_EQ(expectedNodeNumberAtUserSpecifiedLocation, thisConstruct.NodeUserTemp);
 }
+
+TEST_F(EnergyPlusFixture, DataHeatBalance_AssignReverseConstructionNumberTest)
+{
+    int ConstrNum;
+    int expectedResultRevConstrNum;
+    int functionResultRevConstrNum;
+    bool ErrorsFound = false;
+
+    state->dataHeatBal->TotConstructs = 2;
+    state->dataConstruction->Construct.allocate(state->dataHeatBal->TotConstructs);
+    state->dataConstruction->LayerPoint.allocate(Construction::MaxLayersInConstruct);
+
+    auto &thisConstruct(state->dataConstruction->Construct(1));
+    auto &otherConstruct(state->dataConstruction->Construct(2));
+
+    // Test: For an interzone surface that uses the zone as the other side, a new
+    //       interzone surface for that zone has to be created.  That interzone has
+    //       to have the reversed construction.  If that reversed construction is
+    //       not used for any defined surface, the variable IsUsed is false.  However,
+    //       since it now is being used, IsUsed has to be set to true.  Prior to
+    //       work on Defect #8919, when using CondFD and a zone other side condition
+    //       for an interzone surface (implied or E+ internally created other side)
+    //       for a construction that was reversed in the input file but not used
+    //       for other defined surfaces, IsUsed was set to false and this construction
+    //       was then skipped in the CondFD routine that calculates the number of
+    //       nodes.  This led to a hard crash.  This test simply makes sure that
+    //       IsUsed is set to true when the reversed construction already exists.
+    ConstrNum = 1;
+    thisConstruct.IsUsed = true;
+    thisConstruct.TotLayers = 2;
+    thisConstruct.LayerPoint.allocate(Construction::MaxLayersInConstruct);
+    thisConstruct.LayerPoint = 0;
+    thisConstruct.LayerPoint(1) = 10;
+    thisConstruct.LayerPoint(2) = 12;
+    otherConstruct.IsUsed = false;
+    otherConstruct.TotLayers = 2;
+    otherConstruct.LayerPoint.allocate(Construction::MaxLayersInConstruct);
+    otherConstruct.LayerPoint = 0;
+    otherConstruct.LayerPoint(1) = 12;
+    otherConstruct.LayerPoint(2) = 10;
+    expectedResultRevConstrNum = 2;
+
+    functionResultRevConstrNum = AssignReverseConstructionNumber(*state, ConstrNum, ErrorsFound);
+    EXPECT_EQ(expectedResultRevConstrNum, functionResultRevConstrNum);
+    EXPECT_TRUE(otherConstruct.IsUsed);
+    EXPECT_FALSE(ErrorsFound);
+}