Increase height of fancyhdr header

Question

How would one increase the height of the \fancyhead{} so that the text in the main body, doesn't collide with the title?

I have the following MWE:

\documentclass[a4paper,10pt,oneside]{article}
\usepackage{fancyhdr}
\usepackage[english]{babel} % Required to compile in Windows
\usepackage[letterspace=150]{microtype}
\usepackage{fontspec}

\pagestyle{fancy}
\setmainfont {Adobe Garamond Pro} % Main document font

\renewcommand{\headrulewidth}{0pt}

\fancyhead[C]{
    \addfontfeature{LetterSpace=20.0}\fontsize{30}{30}\selectfont\scshape Foo Bar Camp Names\\[5mm]
}

\begin{document}
\section*{Foo}
\end{document}

However, the section foo starts right in the header, therefore I want to add some vspace in between header and main body. I tried \vspace, \bigskip, and all other sorts of vertical space commands, but none worked.

Updated MWE:

\documentclass[a4paper,10pt,oneside]{article}
\usepackage{marvosym} % Allows the use of symbols
\usepackage[english]{babel} % Required to compile in Windows
\usepackage[letterspace=150]{microtype}
\usepackage{fontspec}
\usepackage{fancyhdr}
%\usepackage[headheight=110pt]{geometry}

\pagestyle{fancy}
\setmainfont {Adobe Garamond Pro} % Main document font

\renewcommand{\headrulewidth}{0pt}
\setlength{\headheight}{110pt} 

\fancyhead[C]{
    \addfontfeature{LetterSpace=20.0}\fontsize{30}{30}\selectfont\scshape Foo Bar Camp Names\\
}

\fancyfoot[C]{
    \lsstyle
    \scshape{
        \renewcommand{\\}{\ {\large\textperiodcentered}\ }
        Foo Street \\Bar\\Foocountry
    }\\
    {\Large\Letter} foo@bar.com \ {\Large\Telefon} (+001) 000-0000000
}

\begin{document}
\date{} % hide date
\section*{Foo Bar}
\end{document}

Answer 1

You log file says (in the warning)

Package Fancyhdr Warning: \headheight is too small (12.0pt): 
 Make it at least 103.50645pt.
 We now make it that large for the rest of the document.
 This may cause the page layout to be inconsistent, however.

Hence a safe head height will be around 110pt. To change this, you can use

\setlength{\headheight}{110pt} 

or

\usepackage[headheight=110pt,showframe]{geometry}

Code:

\documentclass[a4paper,10pt,oneside]{article}
\usepackage{fancyhdr}
\usepackage[english]{babel} % Required to compile in Windows
\usepackage[letterspace=150]{microtype}
\usepackage{fontspec}
%\setlength{\headheight}{110pt} %%or

\usepackage[headheight=110pt]{geometry}


\pagestyle{fancy}
\setmainfont {Adobe Garamond Pro} % Main document font

\renewcommand{\headrulewidth}{0pt}

\fancyhead[C]{
    \addfontfeature{LetterSpace=20.0}\fontsize{30}{30}\selectfont\scshape Foo Bar Camp Names\\[5mm] %% why this 5mm vertical space??
}

\begin{document}
\section*{Foo}
\end{document}

As a side note, I did not understand the reason for 5mm vertical space you left in the header. I think you tried to correct the spacing. If so, better way is to use geometry and adjust head height. Without this 5mm the head height of 65pt is sufficient.

Update:

To answer the comments below:

\documentclass[a4paper,10pt,oneside]{article}
\usepackage{marvosym} % Allows the use of symbols
\usepackage[english]{babel} % Required to compile in Windows
\usepackage[letterspace=150]{microtype}
\usepackage{fontspec}
\usepackage{fancyhdr}
\usepackage[top=1.5in,bottom=1in,right=1in,left=1in,headheight=65pt]{geometry}

\pagestyle{fancy}
\setmainfont {Adobe Garamond Pro} % Main document font

\renewcommand{\headrulewidth}{0pt}
%\setlength{\headheight}{95pt}

\fancyhead[C]{
    \addfontfeature{LetterSpace=20.0}\fontsize{30}{30}\selectfont\scshape Foo Bar Camp Names
}

\fancyfoot[C]{
    \lsstyle
    \scshape{
        \renewcommand{\\}{\ {\large\textperiodcentered}\ }
        Foo Street \\Bar\\Foocountry
    }\\
    {\Large\Letter} foo@bar.com \ {\Large\Telefon} (+001) 000-0000000
}

\begin{document}
\date{} % hide date
\section*{Foo Bar}
\end{document}

The gap between the header and the main body is decided by the length headsep. This can be controlled by the option (to geometry) as headsep=1cm (change the length 1cm as needed):

\usepackage[top=1.5in,bottom=1in,right=1in,left=1in,headheight=65pt,headsep=1cm]{geometry}