How to rewrite variadic template of type T to specific (non-primitive) type

I have this code, which fills my row structure with string data for each column.

    struct row_t
    {
        row_t()
        {};
        template<typename ...T>
        row_t(const T& ...var)
        {
            append(var...);
        }
        template<typename T, typename ...Types>
        void append(const T &var1, const Types& ...var2)
        {
           // here should be some kind of check, that number of arguments == COLUMN_COUNT
            data.append_copy(var1);
            append(var2...);
        }
        template<typename T>
        void append(const T &var1)
        {
            data.append_copy(var1);
        }

        array_local_t<sstring_t, COLUMN_COUNT> data; // my implementation of arrays
    };

and I can call is like this:

row_t tmp_row(a,b,c,d);
//with a, b, c, d being my sstring_t types

Now, as you might noticed, my data array is of type sstring_t. So If i tried to call this with a,b,c,d being int, I would not be able to compile the code -> I don't need or want the template functions to be of Typename T, but only sstring_t, because that is the only thing that makes sense in my case (so I dont want to change data array to type T and call it a day). I was only able to write the code like this. Can you help me to convert it to specific type only(sstring_t) using C++11 max?