diff --git a/SharpCompress/Archive/AbstractWritableArchive.cs b/SharpCompress/Archive/AbstractWritableArchive.cs
index 7cf81902..2eb10d13 100644
--- a/SharpCompress/Archive/AbstractWritableArchive.cs
+++ b/SharpCompress/Archive/AbstractWritableArchive.cs
@@ -97,7 +97,17 @@ namespace SharpCompress.Archive
             SaveTo(stream, compressionType, OldEntries, newEntries);
         }
 
-        protected abstract TEntry CreateEntry(string filePath, Stream source, long size, DateTime? modified,
+        protected TEntry CreateEntry(string filePath, Stream source, long size, DateTime? modified,
+            bool closeStream)
+        {
+            if (!source.CanRead || !source.CanSeek)
+            {
+                throw new ArgumentException("Streams must be readable and seekable to use the Writing Archive API");
+            }
+            return CreateEntryInternal(filePath, source, size, modified, closeStream);
+        }
+
+        protected abstract TEntry CreateEntryInternal(string filePath, Stream source, long size, DateTime? modified,
                                               bool closeStream);
 
         protected abstract void SaveTo(Stream stream, CompressionInfo compressionType,
diff --git a/SharpCompress/Archive/GZip/GZipArchive.cs b/SharpCompress/Archive/GZip/GZipArchive.cs
index eea5b89d..7c8e0c5f 100644
--- a/SharpCompress/Archive/GZip/GZipArchive.cs
+++ b/SharpCompress/Archive/GZip/GZipArchive.cs
@@ -158,10 +158,10 @@ namespace SharpCompress.Archive.GZip
 
         public void SaveTo(Stream stream)
         {
-            this.SaveTo(stream, CompressionType.GZip);
+            SaveTo(stream, CompressionType.GZip);
         }
 
-        protected override GZipArchiveEntry CreateEntry(string filePath, Stream source, long size, DateTime? modified,
+        protected override GZipArchiveEntry CreateEntryInternal(string filePath, Stream source, long size, DateTime? modified,
                                                         bool closeStream)
         {
             if (Entries.Any())
diff --git a/SharpCompress/Archive/Tar/TarArchive.cs b/SharpCompress/Archive/Tar/TarArchive.cs
index f464c2da..e3e7b838 100644
--- a/SharpCompress/Archive/Tar/TarArchive.cs
+++ b/SharpCompress/Archive/Tar/TarArchive.cs
@@ -183,7 +183,7 @@ namespace SharpCompress.Archive.Tar
             return new TarArchive();
         }
 
-        protected override TarArchiveEntry CreateEntry(string filePath, Stream source,
+        protected override TarArchiveEntry CreateEntryInternal(string filePath, Stream source,
                                                        long size, DateTime? modified, bool closeStream)
         {
             return new TarWritableArchiveEntry(this, source, CompressionType.Unknown, filePath, size, modified,
diff --git a/SharpCompress/Archive/Tar/TarArchiveEntry.cs b/SharpCompress/Archive/Tar/TarArchiveEntry.cs
index 5c3d8e95..a4622dc5 100644
--- a/SharpCompress/Archive/Tar/TarArchiveEntry.cs
+++ b/SharpCompress/Archive/Tar/TarArchiveEntry.cs
@@ -7,7 +7,7 @@ namespace SharpCompress.Archive.Tar
 {
     public class TarArchiveEntry : TarEntry, IArchiveEntry
     {
-        private TarArchive archive;
+        private readonly TarArchive archive;
 
         internal TarArchiveEntry(TarArchive archive, TarFilePart part, CompressionType compressionType)
             : base(part, compressionType)
diff --git a/SharpCompress/Archive/Tar/TarWritableArchiveEntry.cs b/SharpCompress/Archive/Tar/TarWritableArchiveEntry.cs
index 15644ace..82b7de78 100644
--- a/SharpCompress/Archive/Tar/TarWritableArchiveEntry.cs
+++ b/SharpCompress/Archive/Tar/TarWritableArchiveEntry.cs
@@ -8,16 +8,16 @@ namespace SharpCompress.Archive.Tar
 {
     internal class TarWritableArchiveEntry : TarArchiveEntry
     {
-        private string path;
-        private long size;
-        private DateTime? lastModified;
-        private bool closeStream;
+        private readonly string path;
+        private readonly long size;
+        private readonly DateTime? lastModified;
+        private readonly bool closeStream;
 
         internal TarWritableArchiveEntry(TarArchive archive, Stream stream, CompressionType compressionType,
                                          string path, long size, DateTime? lastModified, bool closeStream)
             : base(archive, null, compressionType)
         {
-            this.Stream = stream;
+            Stream = stream;
             this.path = path;
             this.size = size;
             this.lastModified = lastModified;
diff --git a/SharpCompress/Archive/Zip/ZipArchive.cs b/SharpCompress/Archive/Zip/ZipArchive.cs
index 4f5bece8..dea6d7a3 100644
--- a/SharpCompress/Archive/Zip/ZipArchive.cs
+++ b/SharpCompress/Archive/Zip/ZipArchive.cs
@@ -220,7 +220,7 @@ namespace SharpCompress.Archive.Zip
             }
         }
 
-        protected override ZipArchiveEntry CreateEntry(string filePath, Stream source, long size, DateTime? modified,
+        protected override ZipArchiveEntry CreateEntryInternal(string filePath, Stream source, long size, DateTime? modified,
                                                        bool closeStream)
         {
             return new ZipWritableArchiveEntry(this, source, filePath, size, modified, closeStream);
diff --git a/SharpCompress/Archive/Zip/ZipArchiveEntry.cs b/SharpCompress/Archive/Zip/ZipArchiveEntry.cs
index 17ec0cf9..be5ebe5a 100644
--- a/SharpCompress/Archive/Zip/ZipArchiveEntry.cs
+++ b/SharpCompress/Archive/Zip/ZipArchiveEntry.cs
@@ -6,7 +6,7 @@ namespace SharpCompress.Archive.Zip
 {
     public class ZipArchiveEntry : ZipEntry, IArchiveEntry
     {
-        private ZipArchive archive;
+        private readonly ZipArchive archive;
 
         internal ZipArchiveEntry(ZipArchive archive, SeekableZipFilePart part)
             : base(part)