diff --git a/3rdparty/expreval/except.h b/3rdparty/expreval/except.h
index ff8a9be2..d3d3a025 100644
--- a/3rdparty/expreval/except.h
+++ b/3rdparty/expreval/except.h
@@ -69,7 +69,7 @@ namespace ExprEval
     class NotFoundException : public Exception
     {
     public:
-        NotFoundException(const ::std::string &name);
+        explicit NotFoundException(const ::std::string &name);
     };
 
     // Already exists exception (function or value already exists)
@@ -77,7 +77,7 @@ namespace ExprEval
     class AlreadyExistsException : public Exception
     {
     public:
-        AlreadyExistsException(const ::std::string &name);
+        explicit AlreadyExistsException(const ::std::string &name);
     };
 
     // A null pointer was passed
@@ -85,7 +85,7 @@ namespace ExprEval
     class NullPointerException : public Exception
     {
     public:
-        NullPointerException(const ::std::string &method);
+        explicit NullPointerException(const ::std::string &method);
     };
 
     // A bad math error occured
@@ -93,7 +93,7 @@ namespace ExprEval
     class MathException : public Exception
     {
     public:
-        MathException(const ::std::string &function);
+        explicit MathException(const ::std::string &function);
     };
 
     // Divide by zero exception
@@ -150,7 +150,7 @@ namespace ExprEval
     class InvalidArgumentCountException : public Exception
     {
     public:
-        InvalidArgumentCountException(const ::std::string &function);
+        explicit InvalidArgumentCountException(const ::std::string &function);
     };
 
     // Assign to a constant
@@ -158,7 +158,7 @@ namespace ExprEval
     class ConstantAssignException : public Exception
     {
     public:
-        ConstantAssignException(const ::std::string &value);
+        explicit ConstantAssignException(const ::std::string &value);
     };
 
     // Pass constant by reference
@@ -166,7 +166,7 @@ namespace ExprEval
     class ConstantReferenceException : public Exception
     {
     public:
-        ConstantReferenceException(const ::std::string &value);
+        explicit ConstantReferenceException(const ::std::string &value);
     };
 
     // A general syntax exception
diff --git a/3rdparty/expreval/node.h b/3rdparty/expreval/node.h
index 9929207b..c16545a7 100644
--- a/3rdparty/expreval/node.h
+++ b/3rdparty/expreval/node.h
@@ -25,7 +25,7 @@ namespace ExprEval
     class Node
     {
     public:
-        Node(Expression *expr);
+        explicit Node(Expression *expr);
         virtual ~Node();
         
         virtual double DoEvaluate() = 0;
@@ -43,7 +43,7 @@ namespace ExprEval
     class FunctionNode : public Node
     {
     public:
-        FunctionNode(Expression *expr);
+        explicit FunctionNode(Expression *expr);
         ~FunctionNode();
         
         // Parse nodes and references
@@ -81,7 +81,7 @@ namespace ExprEval
     class MultiNode : public Node
     {
     public:
-        MultiNode(Expression *expr);
+        explicit MultiNode(Expression *expr);
         ~MultiNode();
         
         double DoEvaluate();
@@ -97,7 +97,7 @@ namespace ExprEval
     class AssignNode : public Node
     {
     public:
-        AssignNode(Expression *expr);
+        explicit AssignNode(Expression *expr);
         ~AssignNode();
         
         double DoEvaluate();
@@ -114,7 +114,7 @@ namespace ExprEval
     class AddNode : public Node
     {
     public:
-        AddNode(Expression *expr);
+        explicit AddNode(Expression *expr);
         ~AddNode();
         
         double DoEvaluate();
@@ -131,7 +131,7 @@ namespace ExprEval
     class SubtractNode : public Node
     {
     public:
-        SubtractNode(Expression *expr);
+        explicit SubtractNode(Expression *expr);
         ~SubtractNode();
         
         double DoEvaluate();
@@ -148,7 +148,7 @@ namespace ExprEval
     class MultiplyNode : public Node
     {
     public:
-        MultiplyNode(Expression *expr);
+        explicit MultiplyNode(Expression *expr);
         ~MultiplyNode();
         
         double DoEvaluate();
@@ -165,7 +165,7 @@ namespace ExprEval
     class DivideNode : public Node
     {
     public:
-        DivideNode(Expression *expr);
+        explicit DivideNode(Expression *expr);
         ~DivideNode();
         
         double DoEvaluate();
@@ -182,7 +182,7 @@ namespace ExprEval
     class NegateNode : public Node
     {
     public:
-        NegateNode(Expression *expr);
+        explicit NegateNode(Expression *expr);
         ~NegateNode();
         
         double DoEvaluate();
@@ -198,7 +198,7 @@ namespace ExprEval
     class ExponentNode : public Node
     {
     public:
-        ExponentNode(Expression *expr);
+        explicit ExponentNode(Expression *expr);
         ~ExponentNode();
         
         double DoEvaluate();
@@ -215,7 +215,7 @@ namespace ExprEval
     class VariableNode : public Node
     {
     public:
-        VariableNode(Expression *expr);
+        explicit VariableNode(Expression *expr);
         ~VariableNode();
         
         double DoEvaluate();
@@ -231,7 +231,7 @@ namespace ExprEval
     class ValueNode : public Node
     {
     public:
-        ValueNode(Expression *expr);
+        explicit ValueNode(Expression *expr);
         ~ValueNode();
         
         double DoEvaluate();
diff --git a/3rdparty/expreval/parser.h b/3rdparty/expreval/parser.h
index af9da7a1..e7253821 100644
--- a/3rdparty/expreval/parser.h
+++ b/3rdparty/expreval/parser.h
@@ -75,7 +75,7 @@ namespace ExprEval
     public:
         typedef ::std::vector<Token*>::size_type size_type;
     
-        Parser(Expression *expr);
+        explicit Parser(Expression *expr);
         ~Parser();
                     
         Node *Parse(const ::std::string &exstr);
diff --git a/src/ASM/ASMbase.h b/src/ASM/ASMbase.h
index a79b587e..8cd0becf 100644
--- a/src/ASM/ASMbase.h
+++ b/src/ASM/ASMbase.h
@@ -68,7 +68,7 @@ public:
     char RY;  //!< Boundary condition code for Y-rotation
     char RZ;  //!< Boundary condition code for Z-rotation
     //! \brief Constructor initializing a BC instance.
-    BC(int n) : node(n), CX(1), CY(1), CZ(1), RX(1), RY(1), RZ(1) {}
+    explicit BC(int n) : node(n), CX(1), CY(1), CZ(1), RX(1), RY(1), RZ(1) {}
   };
 
   typedef std::vector<BC> BCVec; //!< Nodal boundary condition container
diff --git a/src/ASM/ASMmxBase.h b/src/ASM/ASMmxBase.h
index 24484d74..c4b3bf2e 100644
--- a/src/ASM/ASMmxBase.h
+++ b/src/ASM/ASMmxBase.h
@@ -32,7 +32,7 @@ class ASMmxBase
 protected:
   //! \brief The constructor sets the number of field variables.
   //! \param[in] n_f Number of nodal variables in each field
-  ASMmxBase(const std::vector<unsigned char>& n_f);
+  explicit ASMmxBase(const std::vector<unsigned char>& n_f);
 
   //! \brief Initializes the patch level MADOF array.
   //! \param[in] MLGN Matrix of local-to-global node numbers
diff --git a/src/ASM/ASMs2D.h b/src/ASM/ASMs2D.h
index a93b218c..87c4af7c 100644
--- a/src/ASM/ASMs2D.h
+++ b/src/ASM/ASMs2D.h
@@ -91,7 +91,7 @@ protected:
     const ASMs2D& myPatch; //!< Reference to the patch being integrated
   public:
     //! \brief The constructor initialises the reference to current patch.
-    InterfaceChecker(const ASMs2D& pch) : myPatch(pch) {}
+    explicit InterfaceChecker(const ASMs2D& pch) : myPatch(pch) {}
     //! \brief Empty destructor.
     virtual ~InterfaceChecker() {}
     //! \brief Returns non-zero if the specified element have contributions.
diff --git a/src/ASM/ASMs3D.h b/src/ASM/ASMs3D.h
index d477917a..3d6acb48 100644
--- a/src/ASM/ASMs3D.h
+++ b/src/ASM/ASMs3D.h
@@ -110,7 +110,7 @@ protected:
     const ASMs3D& myPatch; //!< Reference to the patch being integrated
   public:
     //! \brief The constructor initialises the reference to current patch.
-    InterfaceChecker(const ASMs3D& pch) : myPatch(pch) {}
+    explicit InterfaceChecker(const ASMs3D& pch) : myPatch(pch) {}
     //! \brief Empty destructor.
     virtual ~InterfaceChecker() {}
     //! \brief Returns non-zero if the specified element have contributions.
@@ -122,7 +122,7 @@ protected:
 
 public:
   //! \brief Default constructor.
-  ASMs3D(unsigned char n_f = 3);
+  explicit ASMs3D(unsigned char n_f = 3);
   //! \brief Special copy constructor for sharing of FE data.
   ASMs3D(const ASMs3D& patch, unsigned char n_f);
   //! \brief Default copy constructor copying everything.
diff --git a/src/ASM/ASMs3DLag.h b/src/ASM/ASMs3DLag.h
index cc5e97ff..64aac7b1 100644
--- a/src/ASM/ASMs3DLag.h
+++ b/src/ASM/ASMs3DLag.h
@@ -27,7 +27,7 @@ class ASMs3DLag : public ASMs3D
 {
 public:
   //! \brief Default constructor.
-  ASMs3DLag(unsigned char n_f = 3);
+  explicit ASMs3DLag(unsigned char n_f = 3);
   //! \brief Special copy constructor for sharing of FE data.
   ASMs3DLag(const ASMs3DLag& patch, unsigned char n_f);
   //! \brief Default copy constructor copying everything.
diff --git a/src/ASM/ASMs3DSpec.h b/src/ASM/ASMs3DSpec.h
index eedaa520..a61a2136 100644
--- a/src/ASM/ASMs3DSpec.h
+++ b/src/ASM/ASMs3DSpec.h
@@ -26,7 +26,7 @@ class ASMs3DSpec : public ASMs3DLag
 {
 public:
   //! \brief Default constructor.
-  ASMs3DSpec(unsigned char n_f = 3) : ASMs3DLag(n_f) {}
+  explicit ASMs3DSpec(unsigned char n_f = 3) : ASMs3DLag(n_f) {}
   //! \brief Copy constructor.
   ASMs3DSpec(const ASMs3DSpec& patch, unsigned char n_f = 0)
     : ASMs3DLag(patch,n_f) {}
diff --git a/src/ASM/ASMs3Dmx.h b/src/ASM/ASMs3Dmx.h
index 342b350b..e0c909b2 100644
--- a/src/ASM/ASMs3Dmx.h
+++ b/src/ASM/ASMs3Dmx.h
@@ -33,7 +33,7 @@ class ASMs3Dmx : public ASMs3D, private ASMmxBase
 {
 public:
   //! \brief The constructor initializes the dimension of each basis.
-  ASMs3Dmx(const CharVec& n_f);
+  explicit ASMs3Dmx(const CharVec& n_f);
   //! \brief Copy constructor.
   ASMs3Dmx(const ASMs3Dmx& patch, const CharVec& n_f = CharVec(2,0));
   //! \brief Empty destructor.
diff --git a/src/ASM/ASMs3DmxLag.h b/src/ASM/ASMs3DmxLag.h
index eb3f4b59..d66f40ef 100644
--- a/src/ASM/ASMs3DmxLag.h
+++ b/src/ASM/ASMs3DmxLag.h
@@ -30,7 +30,7 @@ class ASMs3DmxLag : public ASMs3DLag, private ASMmxBase
 {
 public:
   //! \brief The constructor initializes the dimension of each basis.
-  ASMs3DmxLag(const CharVec& n_f);
+  explicit ASMs3DmxLag(const CharVec& n_f);
   //! \brief Copy constructor.
   ASMs3DmxLag(const ASMs3DmxLag& patch, const CharVec& n_f = CharVec(2,0));
   //! \brief Empty destructor.
diff --git a/src/ASM/ASMunstruct.h b/src/ASM/ASMunstruct.h
index a46e1d5f..e1e6e1d9 100644
--- a/src/ASM/ASMunstruct.h
+++ b/src/ASM/ASMunstruct.h
@@ -47,7 +47,7 @@ namespace LR //! Utilities for LR-splines.
     RealArray errors;   //!< List of error indicators for the elements
 
     //! \brief Default constructor.
-    RefineData(bool rs = false) : refShare(rs) {}
+    explicit RefineData(bool rs = false) : refShare(rs) {}
   };
 
   //! \brief Expands the basis coefficients of an LR-spline object.
diff --git a/src/ASM/BDFMats.h b/src/ASM/BDFMats.h
index ea5bece8..9f42e153 100644
--- a/src/ASM/BDFMats.h
+++ b/src/ASM/BDFMats.h
@@ -28,7 +28,7 @@ class BDFMats : public NewmarkMats
 public:
   //! \brief The constructor initializes the time integration parameters.
   //! param[in] bdfscheme BDF time discretization scheme
-  BDFMats(const TimeIntegration::BDFD2& bdfscheme) : bdf(bdfscheme) {}
+  explicit BDFMats(const TimeIntegration::BDFD2& bdfscheme) : bdf(bdfscheme) {}
   //! \brief Empty destructor.
   virtual ~BDFMats() {}
 
diff --git a/src/ASM/DomainDecomposition.h b/src/ASM/DomainDecomposition.h
index 7057aef4..1f11a201 100644
--- a/src/ASM/DomainDecomposition.h
+++ b/src/ASM/DomainDecomposition.h
@@ -48,7 +48,7 @@ public:
   class SlaveOrder {
     public:
       //! \brief The constructor initializes the DomainDecomposition reference.
-      SlaveOrder(const DomainDecomposition& dd_) : dd(dd_) {}
+      explicit SlaveOrder(const DomainDecomposition& dd_) : dd(dd_) {}
       //! \brief Hide ill-formed default assignment operator.
       SlaveOrder& operator=(const SlaveOrder&) { return *this; }
       //! \brief Compare interfaces.
diff --git a/src/ASM/ElmNorm.h b/src/ASM/ElmNorm.h
index 38d7e99e..11286287 100644
--- a/src/ASM/ElmNorm.h
+++ b/src/ASM/ElmNorm.h
@@ -39,7 +39,7 @@ public:
   //! by the application, but are only used to assembly the global norms.
   //! To avoid the need for a global array of element norms in that case,
   //! an internal array is then used instead.
-  ElmNorm(size_t n) : buf(n,0.0), nnv(n) { ptr = &buf.front(); }
+  explicit ElmNorm(size_t n) : buf(n,0.0), nnv(n) { ptr = &buf.front(); }
   //! \brief Empty destructor.
   virtual ~ElmNorm() {}
 
diff --git a/src/ASM/Field.h b/src/ASM/Field.h
index 6617fcaf..7349d868 100644
--- a/src/ASM/Field.h
+++ b/src/ASM/Field.h
@@ -31,7 +31,7 @@ class Field
 protected:
   //! \brief The constructor sets the field name.
   //! \param[in] name Optional name of field
-  Field(const char* name = nullptr) { if (name) fname = name; }
+  explicit Field(const char* name = nullptr) { if (name) fname = name; }
 
 public:
   //! \brief Empty destructor.
diff --git a/src/ASM/FieldBase.h b/src/ASM/FieldBase.h
index 0b62f142..4201a7a1 100644
--- a/src/ASM/FieldBase.h
+++ b/src/ASM/FieldBase.h
@@ -31,7 +31,7 @@ class FieldBase : public Field
 protected:
   //! \brief The constructor sets the field name.
   //! \param[in] name Optional name of field
-  FieldBase(const char* name = nullptr) : Field(name) { nelm = nno = 0; }
+  explicit FieldBase(const char* name = nullptr) : Field(name) { nelm = nno = 0; }
 
 public:
   //! \brief Empty destructor.
diff --git a/src/ASM/Fields.h b/src/ASM/Fields.h
index e7ef3c1c..82997384 100644
--- a/src/ASM/Fields.h
+++ b/src/ASM/Fields.h
@@ -36,7 +36,7 @@ class Fields
 protected:
   //! \brief The constructor sets the field name.
   //! \param[in] name Name of field
-  Fields(const char* name = 0) : nf(0), nelm(0), nno(0)
+  explicit Fields(const char* name = 0) : nf(0), nelm(0), nno(0)
   { if (name) fname = name; }
 
 public:
diff --git a/src/ASM/GlbForceVec.h b/src/ASM/GlbForceVec.h
index d86fe1df..77c5fd73 100644
--- a/src/ASM/GlbForceVec.h
+++ b/src/ASM/GlbForceVec.h
@@ -31,7 +31,7 @@ class GlbForceVec : public GlobalIntegral
 {
 public:
   //! \brief The constructor only sets its reference to the SAM object.
-  GlbForceVec(const SAM& _sam) : sam(_sam) {}
+  explicit GlbForceVec(const SAM& _sam) : sam(_sam) {}
   //! \brief Empty destructor.
   virtual ~GlbForceVec() {}
 
diff --git a/src/ASM/IBGeometries.h b/src/ASM/IBGeometries.h
index 488aada4..b4374c99 100644
--- a/src/ASM/IBGeometries.h
+++ b/src/ASM/IBGeometries.h
@@ -93,7 +93,7 @@ public:
   //! \brief Default constructor.
   PerforatedPlate2D() {}
   //! \brief Constructor creating a single hole.
-  PerforatedPlate2D(Hole2D* hole) { holes.resize(1,hole); }
+  explicit PerforatedPlate2D(Hole2D* hole) { holes.resize(1,hole); }
   //! \brief The destructor deletes the holes.
   virtual ~PerforatedPlate2D();
 
diff --git a/src/ASM/ImmersedBoundaries.C b/src/ASM/ImmersedBoundaries.C
index 6b3814ac..b621c9a7 100644
--- a/src/ASM/ImmersedBoundaries.C
+++ b/src/ASM/ImmersedBoundaries.C
@@ -63,7 +63,7 @@ struct cell
   vertex CellVerts[4]; //!< Global coordinates of the cell vertices
 
   //! \brief Default constructor.
-  cell(int level = 0) : depth(level), xi(0.0), eta(0.0) {}
+  explicit cell(int level = 0) : depth(level), xi(0.0), eta(0.0) {}
 };
 
 
diff --git a/src/ASM/IntegrandBase.h b/src/ASM/IntegrandBase.h
index 9ee6f681..48b3ed90 100644
--- a/src/ASM/IntegrandBase.h
+++ b/src/ASM/IntegrandBase.h
@@ -41,7 +41,7 @@ class IntegrandBase : public Integrand
 {
 protected:
   //! \brief The default constructor is protected to allow sub-classes only.
-  IntegrandBase(unsigned short int n = 0) : nsd(n), npv(1), m_mode(SIM::INIT) {}
+  explicit IntegrandBase(unsigned short int n = 0) : nsd(n), npv(1), m_mode(SIM::INIT) {}
 
 public:
   //! \brief Empty destructor.
@@ -285,8 +285,8 @@ class NormBase : public Integrand
 {
 protected:
   //! \brief The default constructor is protected to allow sub-classes only.
-  NormBase(IntegrandBase& p) : myProblem(p), projBou(false), nrcmp(0),
-                               lints(nullptr), finalOp(ASM::SQRT) {}
+  explicit NormBase(IntegrandBase& p) : myProblem(p), projBou(false), nrcmp(0),
+                                        lints(nullptr), finalOp(ASM::SQRT) {}
 
 public:
   //! \brief Empty destructor.
@@ -392,7 +392,7 @@ class ForceBase : public Integrand
 {
 protected:
   //! \brief The constructor is protected to allow sub-classes only.
-  ForceBase(IntegrandBase& p) : myProblem(p), eBuffer(nullptr) {}
+  explicit ForceBase(IntegrandBase& p) : myProblem(p), eBuffer(nullptr) {}
 
 public:
   //! \brief The destructor frees the internally allocated objects.
diff --git a/src/ASM/LR/ASMu3D.h b/src/ASM/LR/ASMu3D.h
index 9b5e18ce..fd668522 100644
--- a/src/ASM/LR/ASMu3D.h
+++ b/src/ASM/LR/ASMu3D.h
@@ -39,7 +39,7 @@ class ASMu3D : public ASMunstruct, public ASM3D
 {
 public:
   //! \brief Default constructor.
-  ASMu3D(unsigned char n_f = 3);
+  explicit ASMu3D(unsigned char n_f = 3);
   //! \brief Copy constructor.
   ASMu3D(const ASMu3D& patch, unsigned char n_f = 0);
   //! \brief Empty destructor.
diff --git a/src/ASM/Lagrange.h b/src/ASM/Lagrange.h
index 4b082eed..2bcb31af 100644
--- a/src/ASM/Lagrange.h
+++ b/src/ASM/Lagrange.h
@@ -26,7 +26,7 @@ class Lagrange
 public:
   //! \brief Constructor initializing the reference to natural coordinates.
   //! \param[in] p Natural interpolation point coordinates in range [-1,1]
-  Lagrange(const RealArray& p) : points(p) {}
+  explicit Lagrange(const RealArray& p) : points(p) {}
 
   //! \brief Evaluates a 1D Lagrange polynomial.
   //! \param[in] polnum Which polynomial of the basis to evaluate
diff --git a/src/LinAlg/ISTLMatrix.h b/src/LinAlg/ISTLMatrix.h
index 1e68d6a7..9f00a152 100644
--- a/src/LinAlg/ISTLMatrix.h
+++ b/src/LinAlg/ISTLMatrix.h
@@ -33,7 +33,7 @@ class ISTLVector : public StdVector
 {
 public:
   //! \brief Constructor creating an empty vector.
-  ISTLVector(const ProcessAdm& padm);
+  explicit ISTLVector(const ProcessAdm& padm);
   //! \brief Constructor creating a vector of length \a n.
   ISTLVector(const ProcessAdm& padm, size_t n);
   //! \brief Constructor creating a vector from an array.
diff --git a/src/LinAlg/ISTLSupport.h b/src/LinAlg/ISTLSupport.h
index c9fafaad..d86949ad 100644
--- a/src/LinAlg/ISTLSupport.h
+++ b/src/LinAlg/ISTLSupport.h
@@ -43,7 +43,7 @@ namespace ISTL
   class IOp2Pre : public Dune::InverseOperator2Preconditioner<Pre<ISTL::Mat>, Dune::SolverCategory::sequential> {
     typedef Dune::InverseOperator2Preconditioner<Pre<ISTL::Mat>, Dune::SolverCategory::sequential> SolverType;
   public:
-    IOp2Pre(Pre<ISTL::Mat>* iop) : SolverType(*iop)
+    explicit IOp2Pre(Pre<ISTL::Mat>* iop) : SolverType(*iop)
     {
       m_op.reset(iop);
     }
diff --git a/src/LinAlg/PETScMatrix.h b/src/LinAlg/PETScMatrix.h
index 88a332f5..e5e8a184 100644
--- a/src/LinAlg/PETScMatrix.h
+++ b/src/LinAlg/PETScMatrix.h
@@ -39,7 +39,7 @@ class PETScVector : public StdVector
 {
 public:
   //! \brief Constructor creating an empty vector.
-  PETScVector(const ProcessAdm& padm);
+  explicit PETScVector(const ProcessAdm& padm);
   //! \brief Constructor creating a vector of length \a n.
   PETScVector(const ProcessAdm& padm, size_t n);
   //! \brief Constructor creating a vector from an array.
diff --git a/src/LinAlg/ProcessAdm.h b/src/LinAlg/ProcessAdm.h
index 73004f21..a46565b1 100644
--- a/src/LinAlg/ProcessAdm.h
+++ b/src/LinAlg/ProcessAdm.h
@@ -48,13 +48,13 @@ public:
   ProcessAdm();
 #if defined(HAS_PETSC) || defined(HAVE_MPI)
   //! \brief Construct a parallel process administrator.
-  ProcessAdm(MPI_Comm& mpi_comm);
+  explicit ProcessAdm(MPI_Comm& mpi_comm);
 #endif
 
 #ifdef HAVE_MPI
   //! \brief Construct a parallel process administrator.
   //! \details This overload is necessary due to MPI_COMM_WORLD being .. ickily.
-  ProcessAdm(bool hack);
+  explicit ProcessAdm(bool hack);
 #endif
 
   //! \brief The destructor releases the process administrator.
diff --git a/src/LinAlg/SparseMatrix.C b/src/LinAlg/SparseMatrix.C
index ae464374..162af2c3 100644
--- a/src/LinAlg/SparseMatrix.C
+++ b/src/LinAlg/SparseMatrix.C
@@ -59,7 +59,7 @@ struct SuperLUdata
   Real      rpg; //!< Reciprocal pivot growth
 
   //! \brief The constructor initializes the default input options.
-  SuperLUdata(int numThreads = 0)
+  explicit SuperLUdata(int numThreads = 0)
   {
     R = C = 0;
     perm_r = perm_c = etree = 0;
diff --git a/src/LinAlg/SystemMatrix.h b/src/LinAlg/SystemMatrix.h
index f085df5e..a04478ea 100644
--- a/src/LinAlg/SystemMatrix.h
+++ b/src/LinAlg/SystemMatrix.h
@@ -126,11 +126,11 @@ public:
   //! \brief Constructor creating an empty vector.
   StdVector() {}
   //! \brief Constructor creating a vector of length \a n.
-  StdVector(size_t n) : utl::vector<Real>(n) {}
+  explicit StdVector(size_t n) : utl::vector<Real>(n) {}
   //! \brief Constructor creating a vector from an array.
   StdVector(const Real* values, size_t n) : utl::vector<Real>(values,n) {}
   //! \brief Overloaded copy constructor.
-  StdVector(const std::vector<Real>& vec)
+  explicit StdVector(const std::vector<Real>& vec)
   { this->insert(this->end(),vec.begin(),vec.end()); }
 
   //! \brief Returns the vector type.
diff --git a/src/LinAlg/matrix.h b/src/LinAlg/matrix.h
index fbe95e89..a2db0452 100644
--- a/src/LinAlg/matrix.h
+++ b/src/LinAlg/matrix.h
@@ -61,7 +61,7 @@ namespace utl //! General utility classes and functions.
     //! \brief Constructor creating an empty vector.
     vector<T>() {}
     //! \brief Constructor creating a vector of length \a n.
-    vector<T>(size_t n) { this->resize(n); }
+    explicit vector<T>(size_t n) { this->resize(n); }
     //! \brief Constructor creating a vector from an array.
     vector<T>(const T* values, size_t n) { this->fill(values,n); }
 
diff --git a/src/SIM/EigenModeSIM.h b/src/SIM/EigenModeSIM.h
index a5d19712..a0d2bd2c 100644
--- a/src/SIM/EigenModeSIM.h
+++ b/src/SIM/EigenModeSIM.h
@@ -26,7 +26,7 @@ class EigenModeSIM : public MultiStepSIM
 {
 public:
   //! \brief The constructor initializes the FE model reference.
-  EigenModeSIM(SIMbase& sim);
+  explicit EigenModeSIM(SIMbase& sim);
   //! \brief Empty destructor.
   virtual ~EigenModeSIM() {}
 
diff --git a/src/SIM/GenAlphaSIM.h b/src/SIM/GenAlphaSIM.h
index a2480d97..9d9204d0 100644
--- a/src/SIM/GenAlphaSIM.h
+++ b/src/SIM/GenAlphaSIM.h
@@ -25,7 +25,7 @@ class GenAlphaSIM : public NewmarkSIM
 {
 public:
   //! \brief The constructor initializes default solution parameters.
-  GenAlphaSIM(SIMbase& s);
+  explicit GenAlphaSIM(SIMbase& s);
   //! \brief Empty destructor.
   virtual ~GenAlphaSIM() {}
 
diff --git a/src/SIM/HHTSIM.h b/src/SIM/HHTSIM.h
index c5d6791a..e490f9e8 100644
--- a/src/SIM/HHTSIM.h
+++ b/src/SIM/HHTSIM.h
@@ -175,7 +175,7 @@ class HHTSIM : public NewmarkSIM
 {
 public:
   //! \brief The constructor initializes default solution parameters.
-  HHTSIM(SIMbase& sim);
+  explicit HHTSIM(SIMbase& sim);
   //! \brief Empty destructor.
   virtual ~HHTSIM() {}
 
diff --git a/src/SIM/ModelGenerator.h b/src/SIM/ModelGenerator.h
index a41bfdf4..1f9f0beb 100644
--- a/src/SIM/ModelGenerator.h
+++ b/src/SIM/ModelGenerator.h
@@ -31,7 +31,7 @@ class ModelGenerator
 public:
   //! \brief The constructor initializes the common members.
   //!\ param elem XML element to parse
-  ModelGenerator(const TiXmlElement* elem) : geo(elem) {}
+  explicit ModelGenerator(const TiXmlElement* elem) : geo(elem) {}
   //! \brief Empty destructor.
   virtual ~ModelGenerator() {}
 
@@ -69,7 +69,7 @@ class DefaultGeometry1D : public ModelGenerator
 public:
   //! \brief The constructor forwards to the base class.
   //! \param[in] geo XML element containing geometry definition
-  DefaultGeometry1D(const TiXmlElement* geo) : ModelGenerator(geo) {}
+  explicit DefaultGeometry1D(const TiXmlElement* geo) : ModelGenerator(geo) {}
   //! \brief Empty destructor.
   virtual ~DefaultGeometry1D() {}
 
@@ -93,7 +93,7 @@ class DefaultGeometry2D : public ModelGenerator
 public:
   //! \brief The constructor forwards to the base class.
   //! \param[in] geo XML element containing geometry definition
-  DefaultGeometry2D(const TiXmlElement* geo) : ModelGenerator(geo) {}
+  explicit DefaultGeometry2D(const TiXmlElement* geo) : ModelGenerator(geo) {}
   //! \brief Empty destructor.
   virtual ~DefaultGeometry2D() {}
 
@@ -117,7 +117,7 @@ class DefaultGeometry3D : public ModelGenerator
 public:
   //! \brief The constructor forwards to the base class.
   //! \param[in] geo XML element containing geometry definition
-  DefaultGeometry3D(const TiXmlElement* geo) : ModelGenerator(geo) {}
+  explicit DefaultGeometry3D(const TiXmlElement* geo) : ModelGenerator(geo) {}
   //! \brief Empty destructor.
   virtual ~DefaultGeometry3D() {}
 
diff --git a/src/SIM/MultiStepSIM.h b/src/SIM/MultiStepSIM.h
index a7fecc61..4dac203a 100644
--- a/src/SIM/MultiStepSIM.h
+++ b/src/SIM/MultiStepSIM.h
@@ -36,7 +36,7 @@ protected:
 
   //! \brief The constructor initializes the FE model reference.
   //! \param sim The FE model
-  MultiStepSIM(SIMbase& sim);
+  explicit MultiStepSIM(SIMbase& sim);
 
 public:
   //! \brief Empty destructor.
diff --git a/src/SIM/NewmarkNLSIM.h b/src/SIM/NewmarkNLSIM.h
index 79085f3b..daacd71d 100644
--- a/src/SIM/NewmarkNLSIM.h
+++ b/src/SIM/NewmarkNLSIM.h
@@ -175,7 +175,7 @@ class NewmarkNLSIM : public NewmarkSIM
 {
 public:
   //! \brief The constructor initializes default solution parameters.
-  NewmarkNLSIM(SIMbase& sim);
+  explicit NewmarkNLSIM(SIMbase& sim);
   //! \brief Empty destructor.
   virtual ~NewmarkNLSIM() {}
 
diff --git a/src/SIM/NewmarkSIM.h b/src/SIM/NewmarkSIM.h
index e36acffb..c2ea057b 100644
--- a/src/SIM/NewmarkSIM.h
+++ b/src/SIM/NewmarkSIM.h
@@ -25,7 +25,7 @@ class NewmarkSIM : public MultiStepSIM
 {
 public:
   //! \brief The constructor initializes default solution parameters.
-  NewmarkSIM(SIMbase& sim);
+  explicit NewmarkSIM(SIMbase& sim);
   //! \brief Empty destructor.
   virtual ~NewmarkSIM() {}
 
diff --git a/src/SIM/SIMadmin.h b/src/SIM/SIMadmin.h
index a68f058d..8bf4652d 100644
--- a/src/SIM/SIMadmin.h
+++ b/src/SIM/SIMadmin.h
@@ -32,7 +32,7 @@ class SIMadmin : public XMLInputBase
 {
 protected:
   //! \brief The default constructor initializes the process administrator.
-  SIMadmin(const char* heading = nullptr);
+  explicit SIMadmin(const char* heading = nullptr);
   //! \brief Copy constructor.
   SIMadmin(SIMadmin& anotherSIM);
 
diff --git a/src/SIM/SIMbase.h b/src/SIM/SIMbase.h
index 7c6c53dc..ccf5c7f8 100644
--- a/src/SIM/SIMbase.h
+++ b/src/SIM/SIMbase.h
@@ -62,7 +62,7 @@ class SIMbase : public SIMadmin, public SIMdependency
 {
 protected:
   //! \brief The constructor initializes the pointers to dynamic data members.
-  SIMbase(IntegrandBase* itg = nullptr);
+  explicit SIMbase(IntegrandBase* itg = nullptr);
 
 public:
   //! \brief The destructor frees the dynamically allocated objects.
diff --git a/src/SIM/SIMgeneric.h b/src/SIM/SIMgeneric.h
index a933e583..2b6293e5 100644
--- a/src/SIM/SIMgeneric.h
+++ b/src/SIM/SIMgeneric.h
@@ -28,7 +28,7 @@ class SIMgeneric : public SIMoutput
 {
 protected:
   //! \brief Default constructor.
-  SIMgeneric(IntegrandBase* itg = nullptr) : SIMoutput(itg) {}
+  explicit SIMgeneric(IntegrandBase* itg = nullptr) : SIMoutput(itg) {}
 
 public:
   //! \brief Empty destructor.
diff --git a/src/SIM/SIMinput.h b/src/SIM/SIMinput.h
index 9d5736f1..9d434a6e 100644
--- a/src/SIM/SIMinput.h
+++ b/src/SIM/SIMinput.h
@@ -47,16 +47,16 @@ public:
     //! \brief Default constructor.
     ICInfo() : file_level(-1), geo_level(0), basis(1), component(0) {}
     //! \brief Constructor providing the field name.
-    ICInfo(const std::string& f) : file_level(-1), geo_level(0),
-                                   basis(1), component(0),
-                                   sim_field(f), file_field(f) {}
+    explicit ICInfo(const std::string& f) : file_level(-1), geo_level(0),
+                                            basis(1), component(0),
+                                            sim_field(f), file_field(f) {}
   };
   typedef std::vector<ICInfo> InitialCondVec; //!< Convenience declaration
   typedef std::vector<unsigned char> CharVec; //!< Convenience declaration
 
 protected:
   //! \brief The constructor just forwards to the base class constructor.
-  SIMinput(IntegrandBase* itg = nullptr) : SIMbase(itg), myGen(nullptr) {}
+  explicit SIMinput(IntegrandBase* itg = nullptr) : SIMbase(itg), myGen(nullptr) {}
 
 public:
   //! \brief Empty destructor.
diff --git a/src/SIM/SIMoutput.h b/src/SIM/SIMoutput.h
index f1e39688..4452e27f 100644
--- a/src/SIM/SIMoutput.h
+++ b/src/SIM/SIMoutput.h
@@ -34,7 +34,7 @@ class SIMoutput : public SIMinput
 {
 protected:
   //! \brief The constructor just forwards to the base class constructor.
-  SIMoutput(IntegrandBase* itg);
+  explicit SIMoutput(IntegrandBase* itg);
 
 public:
   //! \brief The destructor frees the dynamically allocated VTF object.
diff --git a/src/Utility/AnaSol.h b/src/Utility/AnaSol.h
index ef1b0a05..8c7a7127 100644
--- a/src/Utility/AnaSol.h
+++ b/src/Utility/AnaSol.h
@@ -65,7 +65,7 @@ public:
 
   //! \brief Constructor initializing the symmetric stress tensor field only.
   //! \param[in] sigma Symmetric stress tensor field
-  AnaSol(STensorFunc* sigma)
+  explicit AnaSol(STensorFunc* sigma)
     : vecSol(nullptr), vecSecSol(nullptr), stressSol(sigma) {}
 
   //! \brief Constructor initializing expression functions by parsing a stream.
diff --git a/src/Utility/BDF.h b/src/Utility/BDF.h
index cd8e3486..021dfb08 100644
--- a/src/Utility/BDF.h
+++ b/src/Utility/BDF.h
@@ -29,7 +29,7 @@ namespace TimeIntegration //! Utilities for time integration.
   public:
     //! \brief Default constructor.
     //! \param[in] order The order of the BDF scheme
-    BDF(int order = 0) : step(0), coefs1(1,1.0) { this->setOrder(order); }
+    explicit BDF(int order = 0) : step(0), coefs1(1,1.0) { this->setOrder(order); }
     //! \brief Empty destructor.
     virtual ~BDF() {}
 
diff --git a/src/Utility/ElementBlock.h b/src/Utility/ElementBlock.h
index 2e219999..08464dfc 100644
--- a/src/Utility/ElementBlock.h
+++ b/src/Utility/ElementBlock.h
@@ -25,7 +25,7 @@ class ElementBlock
 {
 public:
   //! The constructor defines the number of nodes per element \a nenod.
-  ElementBlock(size_t nenod = 8);
+  explicit ElementBlock(size_t nenod = 8);
 
   //! \brief Reallocates the internal arrays to fit a structured grid.
   //! \param[in] nI Number of element in I-direction
diff --git a/src/Utility/FieldFunctions.h b/src/Utility/FieldFunctions.h
index 396a8082..8e0b1927 100644
--- a/src/Utility/FieldFunctions.h
+++ b/src/Utility/FieldFunctions.h
@@ -32,7 +32,7 @@ class FieldFunction : public RealFunc
 
 public:
   //! \brief Default constructor.
-  FieldFunction(Field* f = nullptr) : field(f), pch(nullptr) {}
+  explicit FieldFunction(Field* f = nullptr) : field(f), pch(nullptr) {}
   //! \brief Constructor creating a field from a provided HDF5 file.
   //! \param[in] fileName Name of the HDF5-file
   //! \param[in] basisName Name of the basis which the field values refer to
diff --git a/src/Utility/Function.h b/src/Utility/Function.h
index 83b5cd5a..cd1cf38f 100644
--- a/src/Utility/Function.h
+++ b/src/Utility/Function.h
@@ -100,7 +100,7 @@ namespace utl
   {
   protected:
     //! \brief The constructor is protected to allow sub-class instances only.
-    SpatialFunction(const Result& val) : zero(val) {}
+    explicit SpatialFunction(const Result& val) : zero(val) {}
 
   public:
     //! \brief Empty destructor.
@@ -246,9 +246,9 @@ class TractionField : public TractionFunc
 
 public:
   //! \brief Constructor initializing the symmetric tensor function pointer.
-  TractionField(const STensorFunc& field);
+  explicit TractionField(const STensorFunc& field);
   //! \brief Constructor initializing the tensor function pointer.
-  TractionField(const TensorFunc& field);
+  explicit TractionField(const TensorFunc& field);
   //! \brief Empty destructor.
   virtual ~TractionField() {}
 
diff --git a/src/Utility/Functions.h b/src/Utility/Functions.h
index 8db8f559..677f72f9 100644
--- a/src/Utility/Functions.h
+++ b/src/Utility/Functions.h
@@ -27,7 +27,7 @@ class ConstantFunc : public ScalarFunc
 
 public:
   //! \brief Constructor initializing the function value.
-  ConstantFunc(Real v) : fval(v) {}
+  explicit ConstantFunc(Real v) : fval(v) {}
 
   //! \brief Returns whether the function is identically zero or not.
   virtual bool isZero() const { return fval == Real(0); }
@@ -48,7 +48,7 @@ class LinearFunc : public ScalarFunc
 
 public:
   //! \brief Constructor initializing the function parameter.
-  LinearFunc(Real s = Real(1)) : scale(s) {}
+  explicit LinearFunc(Real s = Real(1)) : scale(s) {}
 
   //! \brief Returns whether the function is identically zero or not.
   virtual bool isZero() const { return scale == Real(0); }
@@ -159,7 +159,7 @@ class ConstFunc : public RealFunc
 
 public:
   //! \brief Constructor initializing the function value.
-  ConstFunc(Real v) : fval(v) {}
+  explicit ConstFunc(Real v) : fval(v) {}
 
   //! \brief Returns whether the function is identically zero or not.
   virtual bool isZero() const { return fval == Real(0); }
@@ -180,7 +180,7 @@ class ConstTimeFunc : public RealFunc
 
 public:
   //! \brief Constructor initializing the function value.
-  ConstTimeFunc(const ScalarFunc* f) : tfunc(f) {}
+  explicit ConstTimeFunc(const ScalarFunc* f) : tfunc(f) {}
   //! \brief The destructor frees the time function.
   virtual ~ConstTimeFunc() { delete tfunc; }
 
@@ -517,7 +517,7 @@ class ConstVecFunc : public VecFunc
 
 public:
   //! \brief Constructor initializing the function value.
-  ConstVecFunc(const Vec3& v) : fval(v) {}
+  explicit ConstVecFunc(const Vec3& v) : fval(v) {}
 
   //! \brief Returns whether the function is identically zero or not.
   virtual bool isZero() const { return fval.isZero(0.0); }
diff --git a/src/Utility/LagrangeInterpolator.h b/src/Utility/LagrangeInterpolator.h
index 25d9f3b2..4c22e9b8 100644
--- a/src/Utility/LagrangeInterpolator.h
+++ b/src/Utility/LagrangeInterpolator.h
@@ -6,7 +6,7 @@
 
 class LagrangeInterpolator {
   public:
-    LagrangeInterpolator(const std::vector<double>& grid_) :
+    explicit LagrangeInterpolator(const std::vector<double>& grid_) :
       grid(grid_)
     {
     }
diff --git a/src/Utility/LogStream.h b/src/Utility/LogStream.h
index 5683d47a..9521c57f 100644
--- a/src/Utility/LogStream.h
+++ b/src/Utility/LogStream.h
@@ -27,7 +27,7 @@ class LogStream
 public:
   //! \brief Default constructor.
   //! \param out The output stream to wrap
-  LogStream(std::ostream* out = nullptr) : m_out(out) { m_ppid = m_pid = 0; }
+  explicit LogStream(std::ostream* out) : m_out(out) { m_ppid = m_pid = 0; }
   //! \brief Constructor initializing the output stream from a reference.
   //! \param out The output stream to wrap
   //! \param ppid The PID to print on
diff --git a/src/Utility/Profiler.h b/src/Utility/Profiler.h
index cd359645..218ebb76 100644
--- a/src/Utility/Profiler.h
+++ b/src/Utility/Profiler.h
@@ -42,7 +42,7 @@ public:
   //! \details The constructor also updates the global static pointer
   //! utl::profiler to point to \a *this, deleting any already pointed-to
   //! object first. This means, only one Profiler object can exist at any time.
-  Profiler(const std::string& name);
+  explicit Profiler(const std::string& name);
   //! \brief The destructor prints the profiling report to the console.
   ~Profiler();
 
@@ -106,7 +106,7 @@ namespace utl
     const char* name; //!< Name tag on the local scope to profile
   public:
     //! \brief The constructor starts the profiling of the named task.
-    prof(const char* tag) : name(tag) { if (profiler) profiler->start(name); }
+    explicit prof(const char* tag) : name(tag) { if (profiler) profiler->start(name); }
     //! \brief The destructor stops the profiling.
     ~prof() { if (profiler) profiler->stop(name); }
   };
diff --git a/src/Utility/TensorFunction.h b/src/Utility/TensorFunction.h
index 3ef9e7a0..28a9866c 100644
--- a/src/Utility/TensorFunction.h
+++ b/src/Utility/TensorFunction.h
@@ -26,7 +26,7 @@ class TensorFunc : public utl::SpatialFunction<Tensor>, public FunctionBase
 {
 protected:
   //! \brief The constructor is protected to allow sub-class instances only.
-  TensorFunc(size_t n = 0) : utl::SpatialFunction<Tensor>(Tensor(n))
+  explicit TensorFunc(size_t n = 0) : utl::SpatialFunction<Tensor>(Tensor(n))
   {
     ncmp = zero.size();
   }
diff --git a/src/Utility/Utilities.C b/src/Utility/Utilities.C
index 5cf4cff4..8c8b3f4a 100644
--- a/src/Utility/Utilities.C
+++ b/src/Utility/Utilities.C
@@ -438,7 +438,7 @@ namespace utl
     int myValue; //!< The integer value to search for
   public:
     //! The constructor initializes the value to search for.
-    cmpInt(int value) : myValue(value) {}
+    explicit cmpInt(int value) : myValue(value) {}
     //! \brief Returns \e true if \a value.second equals \a myValue.
     bool operator()(const std::pair<int,int>& value) const
     {