Hi Awence
The sentence is less than perfect to me as well. It begins with a subordinate clause introduced with a causal for and the next clause begins with and, a coordinating conjunction. After these comes yet another subordinate clause, a relative clause introduced by whose. There is no main clause in the sentence!
What's more, if the speaker wants to use an indefinite article (a) with wall before the relative clause, the comma should be omitted. Using a is justified by the relative clause, though. The simplest way to make the sentence acceptable would be to leave out for at the beginning, which would render the first clause a main clause.
CB