How to spell assess

I've googled and used one line Dictionary, but this is one word that confuses me, as there are several meanings.



In relation to a builder or survey coming out to decided what is the cause of a problem that arises post work.


deciding / making a judgement as to what is the problem, ie. assessing or to assess the situation.

I came up with assess, which is the word I want to use but it still doesn't look right, or am I loosing it.