Incomplete CWI

[marone]

Hi All

 

I've got a mid 1980's detached property that at some point in the past has had the cavity filled with what looks like a type of expanding foam. Whilst refurbishing I've found that there are gaps in the CWI, in particular beneath the 1st floor windows where they are above a single level extension.

 

I've also found that under one of the windows that has been filled, there is a small rodent sized tunnel that has been clawed out (happily there is no sign of the rodent anymore!).

 

I understand that CWI is usually covered by a form of warranty. I'm not sure if the above would be covered by it nor do I have any details on the policy even if it was covered.  

 

So I'm wondering what would be the best course of action here. Is this something that can be fixed (competently) by DIY or should it be something to leave to a professional?

 

Thanks

Phil