diff --git a/opm/core/props/rock/RockFromDeck.cpp b/opm/core/props/rock/RockFromDeck.cpp
index 91af70a80..58e634969 100644
--- a/opm/core/props/rock/RockFromDeck.cpp
+++ b/opm/core/props/rock/RockFromDeck.cpp
@@ -72,6 +72,13 @@ namespace Opm
     {
     }
 
+    RockFromDeck::RockFromDeck(std::size_t number_of_cells)
+        : porosity_(number_of_cells, 0),
+          permeability_(number_of_cells*9, 0.0),
+          permfield_valid_(number_of_cells, false)
+    {
+    }
+
     void RockFromDeck::init(Opm::EclipseStateConstPtr eclState,
                             int number_of_cells, const int* global_cell,
                             const int* cart_dims)
diff --git a/opm/core/props/rock/RockFromDeck.hpp b/opm/core/props/rock/RockFromDeck.hpp
index c0ad9de34..0e202d358 100644
--- a/opm/core/props/rock/RockFromDeck.hpp
+++ b/opm/core/props/rock/RockFromDeck.hpp
@@ -31,10 +31,16 @@ namespace Opm
 
     class RockFromDeck
     {
+        // BlackoilPropsDataHandle needs mutable
+        // access to porosity and permeability
+        friend class BlackoilPropsDataHandle;
+
     public:
         /// Default constructor.
         RockFromDeck();
-
+        /// Creates rock properties with zero porosity and permeability
+        /// \param number_of_cells The number of cells
+        RockFromDeck(std::size_t number_of_cells);
         /// Initialize from deck and cell mapping.
         /// \param  eclState        The EclipseState (processed deck) produced by the opm-parser code
         /// \param  number_of_cells The number of cells in the grid.