Change Page Layout of TCPDF Output

How can I go about changing the default layout of a form created with TCPDF? My main issue is that I need to have a thick blue border around each page of the PDF. I can put a div around my content, but it flexes its height depending on how much text is inside it. On a normal web page I can control that height but I can't seem to be able to do it with TCPDF. Putting a height:500px; or something in the style sheet doesn't change anything.

First, is there a way to change the layout of the TCPDF output?

Second, is there a way to control the height of a div? I've tried doing px and 100% but neither will work for me.

A sample of my code is below:

<style>
td {
    cellpadding: 15px;
}
table {
    border-collapse: collapse;
}
div.borderbox {
border:20px solid #4F81BD;
height:100%;
}

table, th, td {
    border: 1px solid black;
  padding:10px;
}

td.right {

}
td.questions {
    padding-left:10px;
}
ul.workon li {
    margin-left: -20px;
    font-family:arial, helvetica;
    font-size:small;
list-style-type:circle;
}
p {
font-size:small;
font-family:arial, helvetica;
}
p.section {
font-size:medium;
font-weight:bolder;
text-align:center;
}
p.insulator {
font-size:small;
font-weight:bolder;
text-align:center;
line-height:1;
}
p.sectioncount {
font-size:smaller;
text-align:center;
line-height:1;
}
p.notes {
font-size:large;
text-align:center;
font-weight:bolder;
}
strong {
margin:0px;
padding:0px;
}
div.section1notes {
height:300px;
}
</style>
<div class="borderbox">
<p class="section">Evaluator- Section 1</p>
<table>
<tr>
<td class="questions" width="70%">
<br>
<p>1)Question 1-  <strong>{q1}</strong></p>
<p>2) Question 2- <strong>{q2}</strong></p>
</td>
<td class="right" width="30%">
<center>
<p class="insulator">Section topic</p>
<p class="sectioncount">If this section contains 3 or more "No" answers, this is an area that needs attention.</p>
</center>
<p class="insulator">Work with Your Coach to:</p>
<ul class="workon">
<li>Blah line 1</li>
<li>Blah line 2</li>
</ul>
</td>
</tr>
</table>
<div class="section1notes">
<p class="section">~NOTES~</p>
{s1pub}<br/>
{s1prv}
</div>
</div>
<br pagebreak="true"/>

How can I make that div titled section1notes expand to fill the bottom of the page no matter what is written in the s1pub and s1prv area?