Extension class for XmlTextWriter so it doesn't close empty tags and leaves a new line between them. This won't produce A well indented HTML, but the new line will prevent a bad render. Credits: http://goo.gl/Kmi76

CustomHtmlWriter.cs

    public class CustomHtmlWriter: XmlTextWriter
    {
        string openingElement = "";

        //The list could be simply a string, or whatever you need
        List<string> fullyClosedElements = new List<string>(); 

        public CustomHtmlWriter(StringBuilder sb) : base(new StringWriter(sb))
        {
            //The Rest of the tags would be explicitely closed.
            fullyClosedElements.AddRange(new string[] { "br" });
        }

        public override void WriteStartElement(string prefix, string localName, string ns)
        {
            //Generate a new line so the output wont be all in one line
            WriteWhitespace("\n");

            //Save the current tag
            base.WriteStartElement(prefix, localName, ns);
            openingElement = localName;
        }

        public override void WriteEndElement()
        {
            //Close it if needs to
            if (fullyClosedElements.IndexOf(openingElement) < 0)
            {
                WriteFullEndElement();
            }
            else
            {
                base.WriteEndElement();
            }
        }
    }