diff --git a/R/RcppExports.R b/R/RcppExports.R
index ffb204a..b403a44 100644
--- a/R/RcppExports.R
+++ b/R/RcppExports.R
@@ -29,6 +29,14 @@ rcpp_cast_sf <- function(sf, cast_to, close = TRUE) {
     .Call(`_sfheaders_rcpp_cast_sf`, sf, cast_to, close)
 }
 
+rcpp_interleave_sfc <- function(sfc) {
+    .Call(`_sfheaders_rcpp_interleave_sfc`, sfc)
+}
+
+rcpp_interleave_sf <- function(sf) {
+    .Call(`_sfheaders_rcpp_interleave_sf`, sf)
+}
+
 rcpp_fill_list <- function(v, line_ids) {
     .Call(`_sfheaders_rcpp_fill_list`, v, line_ids)
 }
diff --git a/inst/include/sfheaders/interleave/interleave.hpp b/inst/include/sfheaders/interleave/interleave.hpp
index d78df38..299b767 100644
--- a/inst/include/sfheaders/interleave/interleave.hpp
+++ b/inst/include/sfheaders/interleave/interleave.hpp
@@ -3,6 +3,7 @@
 
 #include <Rcpp.h>
 #include "sfheaders/df/sfc.hpp"
+#include "sfheaders/df/sf.hpp"
 #include "sfheaders/utils/lists/list.hpp"
 
 namespace sfheaders {
@@ -66,7 +67,11 @@ namespace interleave {
   }
 
 
-  inline SEXP interleave( Rcpp::List& sfc ) {
+  // TODO: unlist - to unlist some columns (like 'stroke_colour')
+  inline SEXP interleave(
+      Rcpp::List& sfc,
+      R_xlen_t& total_coordinates
+    ) {
 
     // the input will be a long data.frame
     // or an sf object
@@ -82,11 +87,10 @@ namespace interleave {
     R_xlen_t n = sfc.length();
     R_xlen_t i;
 
-    int stride = ( dim_expected == "XYZ" || dim_expected == "XYM" ? 3 : ( dim_expected == "XYZM" ? 4 : 2 ) );
-
-    R_xlen_t total_coordinates = 0;
+    //R_xlen_t total_coordinates = 0;
     Rcpp::List res_list( sfc.size() );
     Rcpp::List res_indices( sfc.size() );
+    Rcpp::IntegerVector sfg_coordinates( sfc.size() );
 
     for( i = 0; i < n; ++i ) {
 
@@ -106,7 +110,12 @@ namespace interleave {
 
       R_xlen_t n_geometries = coords.nrow();
       R_xlen_t n_coordinates = coords( n_geometries - 1, 1 );
-      n_coordinates = n_coordinates + 1;
+
+      // n_coordinates is the total number of coordinates for the given sfg
+      // this is what the data needs to be expanded by.
+      //n_coordinates = n_coordinates + 1;
+      sfg_coordinates[ i ] = n_coordinates;
+
       Rcpp::IntegerVector start_indices = coords( Rcpp::_, 0 );
       start_indices = start_indices + total_coordinates;
 
@@ -116,36 +125,72 @@ namespace interleave {
       total_coordinates = total_coordinates + n_coordinates;
     }
 
-    // TODO: expand the property columns
-    // Rcpp::NumericVector expanded_index( total_coordinates );
-    // R_xlen_t n_col = sf.ncol();
-    // Rcpp::CharacterVector sf_names = sf.names();
-    // R_xlen_t name_position = 0;
-    // for( i = 0; i < n_col; ++i ) {
-    //
-    //   if( sf_names[ i ] != geom_column ) {
-    //
-    //     res_names[ name_position ] = sf_names[ i ];
-    //     SEXP v = sf[ i ];
-    //     expand_vector( res, v, expanded_index, name_position );
-    //     name_position += 1;
-    //   }
-    // }
+    int stride = ( dim_expected == "XYZ" || dim_expected == "XYM" ? 3 : ( dim_expected == "XYZM" ? 4 : 2 ) );
 
     return Rcpp::List::create(
       Rcpp::_["coordinates"] = sfheaders::utils::unlist_list( res_list ),
       Rcpp::_["start_indices"] = sfheaders::utils::unlist_list( res_indices ),
+      Rcpp::_["n_coordinates"] = sfg_coordinates,
+      Rcpp::_["total_coordinates"] = total_coordinates,
       Rcpp::_["stride"] = stride
     );
   }
 
+  inline SEXP interleave( Rcpp::List& sfc ) {
+    R_xlen_t total_coordinates = 0;
+    return interleave( sfc, total_coordinates );
+  }
+
 
   // interleaves an `sf` object
   inline Rcpp::List interleave( Rcpp::DataFrame& sf ) {
     // and expand rows
-    std::string sfc_col = sf.attr("sf_column");
-    Rcpp::List sfc = sf[ sfc_col ];
+    std::string geom_column = sf.attr("sf_column");
+    Rcpp::CharacterVector sf_names = sf.names();
+    Rcpp::List sfc = sf[ geom_column ];
+    R_xlen_t n_col = sf.ncol();
+    R_xlen_t n_geometries = sf.nrow();
+    R_xlen_t i;
+    R_xlen_t j;
+
+    R_xlen_t total_coordinates = 0;
+    Rcpp::List interleaved = interleave( sfc, total_coordinates );
+    Rcpp::IntegerVector n_coordinates = interleaved["n_coordinates"];
+
+    Rcpp::NumericVector expanded_index( total_coordinates );
+    R_xlen_t counter = 0;
+
+    for( i = 0; i < n_geometries; ++i ) {
+      R_xlen_t expand_by = n_coordinates[ i ];
+
+      for( j = 0; j < expand_by; ++j ) {
+        expanded_index[ counter + j ] = i;
+      }
+      counter = counter + expand_by;
+    }
+
+    Rcpp::List res( n_col - 1 );
+    Rcpp::StringVector res_names( n_col - 1 );
+
+    R_xlen_t name_position = 0;
+
+    for( i = 0; i < n_col; ++i ) {
+
+      if( sf_names[ i ] != geom_column ) {
+
+        res_names[ name_position ] = sf_names[ i ];
+        SEXP v = sf[ i ];
+        sfheaders::df::expand_vector( res, v, expanded_index, name_position );
+        name_position += 1;
+      }
+    }
+
+    //res.names() = res_names;
+    Rcpp::DataFrame df = sfheaders::utils::make_dataframe( res, total_coordinates, res_names );
 
+    // construct final object
+    interleaved["data"] = df;
+    return interleaved;
 
   }
 
diff --git a/src/RcppExports.cpp b/src/RcppExports.cpp
index 8f92730..f4cc2d0 100644
--- a/src/RcppExports.cpp
+++ b/src/RcppExports.cpp
@@ -90,6 +90,28 @@ BEGIN_RCPP
     return rcpp_result_gen;
 END_RCPP
 }
+// rcpp_interleave_sfc
+SEXP rcpp_interleave_sfc(Rcpp::List sfc);
+RcppExport SEXP _sfheaders_rcpp_interleave_sfc(SEXP sfcSEXP) {
+BEGIN_RCPP
+    Rcpp::RObject rcpp_result_gen;
+    Rcpp::RNGScope rcpp_rngScope_gen;
+    Rcpp::traits::input_parameter< Rcpp::List >::type sfc(sfcSEXP);
+    rcpp_result_gen = Rcpp::wrap(rcpp_interleave_sfc(sfc));
+    return rcpp_result_gen;
+END_RCPP
+}
+// rcpp_interleave_sf
+SEXP rcpp_interleave_sf(Rcpp::DataFrame sf);
+RcppExport SEXP _sfheaders_rcpp_interleave_sf(SEXP sfSEXP) {
+BEGIN_RCPP
+    Rcpp::RObject rcpp_result_gen;
+    Rcpp::RNGScope rcpp_rngScope_gen;
+    Rcpp::traits::input_parameter< Rcpp::DataFrame >::type sf(sfSEXP);
+    rcpp_result_gen = Rcpp::wrap(rcpp_interleave_sf(sf));
+    return rcpp_result_gen;
+END_RCPP
+}
 // rcpp_fill_list
 Rcpp::List rcpp_fill_list(Rcpp::NumericVector v, Rcpp::IntegerMatrix line_ids);
 RcppExport SEXP _sfheaders_rcpp_fill_list(SEXP vSEXP, SEXP line_idsSEXP) {
@@ -834,6 +856,8 @@ static const R_CallMethodDef CallEntries[] = {
     {"_sfheaders_rcpp_count_new_sfc_objects", (DL_FUNC) &_sfheaders_rcpp_count_new_sfc_objects, 2},
     {"_sfheaders_rcpp_cast_sfc", (DL_FUNC) &_sfheaders_rcpp_cast_sfc, 3},
     {"_sfheaders_rcpp_cast_sf", (DL_FUNC) &_sfheaders_rcpp_cast_sf, 3},
+    {"_sfheaders_rcpp_interleave_sfc", (DL_FUNC) &_sfheaders_rcpp_interleave_sfc, 1},
+    {"_sfheaders_rcpp_interleave_sf", (DL_FUNC) &_sfheaders_rcpp_interleave_sf, 1},
     {"_sfheaders_rcpp_fill_list", (DL_FUNC) &_sfheaders_rcpp_fill_list, 2},
     {"_sfheaders_rcpp_list_sizes", (DL_FUNC) &_sfheaders_rcpp_list_sizes, 1},
     {"_sfheaders_rcpp_list_type", (DL_FUNC) &_sfheaders_rcpp_list_type, 1},
diff --git a/src/interleave.cpp b/src/interleave.cpp
index e350979..d246417 100644
--- a/src/interleave.cpp
+++ b/src/interleave.cpp
@@ -7,6 +7,15 @@ void interleave_geometry(SEXP& sfg, Rcpp::NumericVector& res, R_xlen_t& coordina
 
 }
 
+// [[Rcpp::export]]
+SEXP rcpp_interleave_sfc( Rcpp::List sfc ) {
+  return sfheaders::interleave::interleave( sfc );
+}
+
+// [[Rcpp::export]]
+SEXP rcpp_interleave_sf( Rcpp::DataFrame sf ) {
+  return sfheaders::interleave::interleave( sf );
+}
 
 // SEXP rcpp_interleave( Rcpp::List sfc ) {
 //