diff --git a/src/TSFrame.jl b/src/TSFrame.jl
index 94a5426..705794d 100644
--- a/src/TSFrame.jl
+++ b/src/TSFrame.jl
@@ -398,7 +398,7 @@ end
 # FIXME: use Metadata.jl
 function TSFrame(coredata::AbstractArray{T,2}; colnames=:auto, issorted = false, copycols = true) where {T}
     index_vals = collect(Base.OneTo(size(coredata)[1]))
-    df = DataFrame(coredata, colnames, copycols=true)
+    df = DataFrame(coredata, colnames, copycols=copycols)
     TSFrame(df, index_vals; issorted = issorted, copycols = copycols)
 end
 
@@ -410,7 +410,7 @@ end
 function TSFrame(IndexType::DataType; n::Int=1, issorted = false, copycols = true)
     (n>=1) || throw(DomainError(n, "n should be >= 1"))
     df = DataFrame(fill([],n), :auto)
-    df.Index = IndexType[]
+    insertcols!(df, 1, :Index => IndexType[]; after = false, copycols = false)
     TSFrame(df; issorted = issorted, copycols = copycols)
 end
 
diff --git a/src/rollapply.jl b/src/rollapply.jl
index ce68940..3cf0d3a 100644
--- a/src/rollapply.jl
+++ b/src/rollapply.jl
@@ -84,7 +84,7 @@ function rollapply(ts::TSFrame, fun::Function, windowsize::Int; bycolumn=true)
 
     if bycolumn
         DataFrames.rename!(res, [col => string("rolling_", col, "_", Symbol(fun)) for col in propertynames(res)])
-        res[:, :Index] = TSFrames.index(ts)[windowsize:end]
+        DataFrames.insertcols!(res, 1, :Index => TSFrames.index(ts)[windowsize:end]; after = false, copycols = false)
         return TSFrame(res)
     else
         res_df = DataFrame(Index=TSFrames.index(ts)[windowsize:end], outputs=res)