diff --git a/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionList.C b/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionList.C
index 4f53af759f..83a4ac4c8e 100644
--- a/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionList.C
+++ b/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionList.C
@@ -37,7 +37,7 @@ void Foam::DirectInteractionList<ParticleType>::buildDirectInteractionList
 {
     Info<< "    Building list of direct interaction neighbours" << endl;
 
-    const polyMesh& mesh(il_.mesh());
+    const polyMesh& mesh = il_.mesh();
 
     List<DynamicList<label> > DirectInteractionList(mesh.nCells());
 
@@ -294,9 +294,94 @@ void Foam::DirectInteractionList<ParticleType>::buildDirectInteractionList
 
     // sorting DILs
 
-    forAll((*this), dIL)
+    forAll((*this), dilI)
     {
-        sort((*this)[dIL]);
+        sort((*this)[dilI]);
+    }
+}
+
+
+template<class ParticleType>
+void Foam::DirectInteractionList<ParticleType>::buildWallFaces()
+{
+    Info<< "    Building list of wall faces in range of cells" << endl;
+
+    const polyMesh& mesh = il_.mesh();
+
+    // DynamicLists for data gathering
+    DynamicList<label> thisCellOnlyWallFaces;
+    DynamicList<label> otherCellOnlyWallFaces;
+
+    forAll(wallFaces_, thisCellI)
+    {
+        // Find all of the wall faces for the current cell
+
+        const labelList& thisCellFaces = mesh.cells()[thisCellI];
+
+        labelList& thisCellWallFaces = wallFaces_[thisCellI];
+
+        thisCellOnlyWallFaces.clear();
+
+        forAll(thisCellFaces, tCFI)
+        {
+            label faceI = thisCellFaces[tCFI];
+
+            if (!mesh.isInternalFace(faceI))
+            {
+                label patchI =  mesh.boundaryMesh().whichPatch(faceI);
+                const polyPatch& patch = mesh.boundaryMesh()[patchI];
+
+                // move reference point for wall
+                if (isA<wallPolyPatch>(patch))
+                {
+                    thisCellOnlyWallFaces.append(faceI);
+                }
+            }
+        }
+
+        // Add all the found wall faces to this cell's list, and
+        // retain the wall faces for this cell only to add to other
+        // cells.
+        thisCellWallFaces.append(thisCellOnlyWallFaces);
+
+        // Loop over all of the cells in the DIL for this cell, adding
+        // the wallFaces for this cell to the other cell's wallFace
+        // list, and all of the wallFaces for the other cell to this
+        // cell's list
+
+        const labelList& dil = (*this)[thisCellI];
+
+        forAll(dil, i)
+        {
+            label otherCellI = dil[i];
+
+            const labelList& otherCellFaces = mesh.cells()[otherCellI];
+
+            labelList& otherCellWallFaces = wallFaces_[otherCellI];
+
+            otherCellOnlyWallFaces.clear();
+
+            forAll(otherCellFaces, oCFI)
+            {
+                label faceI = otherCellFaces[oCFI];
+
+                if (!mesh.isInternalFace(faceI))
+                {
+                    label patchI =  mesh.boundaryMesh().whichPatch(faceI);
+                    const polyPatch& patch = mesh.boundaryMesh()[patchI];
+
+                    // move reference point for wall
+                    if (isA<wallPolyPatch>(patch))
+                    {
+                        otherCellOnlyWallFaces.append(faceI);
+                    }
+                }
+            }
+
+            thisCellWallFaces.append(otherCellOnlyWallFaces);
+
+            otherCellWallFaces.append(thisCellOnlyWallFaces);
+        }
     }
 }
 
@@ -311,7 +396,8 @@ Foam::DirectInteractionList<ParticleType>::DirectInteractionList
 )
 :
     labelListList(il.mesh().nCells()),
-    il_(il)
+    il_(il),
+    wallFaces_(il.mesh().nCells())
 {
     if ((*this).size() > 1)
     {
@@ -324,6 +410,8 @@ Foam::DirectInteractionList<ParticleType>::DirectInteractionList
 
         (*this)[0].setSize(0);
     }
+
+    buildWallFaces();
 }
 
 
@@ -334,7 +422,8 @@ Foam::DirectInteractionList<ParticleType>::DirectInteractionList
 )
 :
     labelListList(il.mesh().nCells()),
-    il_(il)
+    il_(il),
+    wallFaces_(il.mesh().nCells())
 {
     Info<< "    Read DirectInteractionList from disk not implemented" << endl;
 }
diff --git a/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionList.H b/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionList.H
index d85bd06190..f3acc18bfb 100644
--- a/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionList.H
+++ b/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionList.H
@@ -59,8 +59,13 @@ class DirectInteractionList
 {
     // Private data
 
+        //- A reference to the InteractionLists object holding this object
         const InteractionLists<ParticleType>& il_;
 
+        //- Data specifying which patch faces of type "wall" are in range
+        //  of each cell
+        labelListList wallFaces_;
+
 
     // Private Member Functions
 
@@ -69,6 +74,8 @@ class DirectInteractionList
             bool pointPointListBuild
         );
 
+        void buildWallFaces();
+
         //- Disallow default bitwise copy construct
         DirectInteractionList(const DirectInteractionList&);
 
@@ -103,6 +110,8 @@ public:
 
         // Access
 
+        inline const labelListList& wallFaces() const;
+
         inline const InteractionLists<ParticleType>& il() const;
 };
 
diff --git a/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionListI.H b/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionListI.H
index e422373b44..9611a033d6 100644
--- a/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionListI.H
+++ b/src/lagrangian/basic/InteractionLists/DirectInteractionList/DirectInteractionListI.H
@@ -26,6 +26,14 @@ License
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+template<class ParticleType>
+inline const Foam::labelListList&
+Foam::DirectInteractionList<ParticleType>::wallFaces() const
+{
+    return wallFaces_;
+}
+
+
 template<class ParticleType>
 inline const Foam::InteractionLists<ParticleType>&
 Foam::DirectInteractionList<ParticleType>::il() const
diff --git a/src/lagrangian/basic/InteractionLists/ReferredCellList/ReferredCell/ReferredCell.C b/src/lagrangian/basic/InteractionLists/ReferredCellList/ReferredCell/ReferredCell.C
index fa32d375c2..8a0003c119 100644
--- a/src/lagrangian/basic/InteractionLists/ReferredCellList/ReferredCell/ReferredCell.C
+++ b/src/lagrangian/basic/InteractionLists/ReferredCellList/ReferredCell/ReferredCell.C
@@ -156,7 +156,7 @@ void Foam::ReferredCell<ParticleType>::locallyMapFaceList
     {
         const labelList& sourceCellFace(sourceCellFaces[sCF]);
 
-        labelList& localFace(faces_[sCF]);
+        face& localFace(faces_[sCF]);
 
         localFace.setSize(sourceCellFace.size());