I have a longtabu looking like this:

As you can see text on multiple lines breaks the bottom line of the cell. How can this be avoided in general for all the cells in the longtabu?
My longtabu code:
\noindent \begin{longtabu}{| p{4.2cm} | >{\centering\arraybackslash}
p{1cm} | >{\centering\arraybackslash} p{1.3cm} *3{|X[c]} |
>{\centering\arraybackslash} p{1cm} |}
\hline \multicolumn{7}{|c|}{\large{Arkitekturvægtning af \textit{use case} 3, 4 og 5}}\\
\hline \textbf{Kvalitetsattribut} & \textbf{Vægt} & \textbf{BP\textsubscript{ED}} & \textbf{BP\textsubscript{DDG}} &
\textbf{BP\textsubscript{AED}} & \textbf{BP\textsubscript{LDS}} &
\textbf{BP\textsubscript{S}} \\
\hline Intern netværkskommunikation & 4 & 5 (20) & 3 (12)
& 4 (16) & 2 (8)
& 3 (12)\\
\hline Tid for backup & 4 & 5 (20) & 3 (12)
& 5 (20) & 2 (8)
& 5 (20)\\
\hline Nedetid & 5 & 5 (25) & 4 (20)
& 3 (15) & 3 (15)
& 1 (5)\\
\hline Kodens kompleksitet & 3 & 5 (15) & 3 (15)
& 3 (15) & 2 (6)
& 4 (13)\\
\hline Forståelsen kompleksitet & 2 & 5 (10) & 5 (10)
& 5 (10) & 4 (8)
& 4 (8)\\
\hline Hukommelsesforbrug & 5 & 1 (5) & 3 (15)
& 5 (25) & 4 (20)
& 5 (25)\\
\hline CPU forbrug & 4 & 5 (20) & 2 (8)
& 3 (12) & 2 (8)
& 4 (16)\\
\hline Overførselsfejlrate & 2 & 5 (10) & 5 (10)
& 5 (10) & 4 (8)
& 2 (4)\\
\noalign{\arrayrulewidth1pt}
\hline
\noalign{\arrayrulewidth0.4pt}
\hline Vægtet sum & & 125 & 96 & 117
& 81 & 102
\\
\hline\caption[Kvalitetsattributter angående backup i \textit{use case} 3-5]{Vægtning at kvalitetsatributter i forhold til \textit{use
case} 3-5.\label{tab:KvalitetBackup}} \end{longtabu}
\strutin the problematic cells. You may also try a\tabulinesep=3ptbefore the tabu-environment. – Sveinung Oct 14 '14 at 10:11