spacing between on page in wbe page composer

Below is the code, I am using to define a rowspan.

<table width="100%" valign="top" cellspacing="10">

<tbody align="top">

<tr>

<td rowspan="3" width ="20%" valign = "top" cellpadding="20%" >

<div><wpc:container id="m3"/></div>

<div><wpc:container id="m6"/></div>

<div><wpc:container id="m9"/></div>

</td>

</tr>

</table>

But, when I add content to these containers. I don't see cell spacing. Can anyone suggest me. How I have the spacing between them.