Dynamic layout and Controls

Hi,
I am developing site in which admin can change layout, e.g. changing layout to 2 or 3 or 4 column layout.
Admin also can manage position of different sections of page like highlights, ads, menus. I have created user controls for these sections so that I can use them in dynamic layout. All these things are stored in database.
So when end user requests page, each time I have to build table layout using settings in database. But building layout with controls for each page is very expensive considering performence. What I am thinking of is to store layout in .htm file when admin changes it. e.g. layout.htm like this:
<table width="100%">
        <tr>
           <td>
              [UserControl1]
         &nb ...