most of them were made of woods/wood and mud

[diamondcutter]

In the 1960’s the living conditions in my hometown were poor. Big families were crowed into small houses and most of them were made of woods and mud.
Source: from one of my students’ composition.

In the second sentence, I think both “woods” and “wood” are correct but the later is more common because in this context people usually use the general idea of the uncountable noun “wood” and it’s not so necessary to emphasize different kinds of woods. What do you say?

 

[5jj]

Use only the non-count form.

 

[teechar]

diamondcutter, if you look up "woods" in the dictionary, you'll understand why it's not possible in the sentence you quoted.

 

[diamondcutter]

But I found this example in Oxford Advanced Learner's Dictionary:
furniture made of a variety of different woods

wood noun - Definition, pictures, pronunciation and usage notes | Oxford Advanced Learner's Dictionary at OxfordLearnersDictionaries.com

Definition of wood noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

www.oxfordlearnersdictionaries.com

 

[5jj]

furniture made of a variety of different woods

The reference is to types of wood.

In the 1960’s the living conditions in my hometown were poor. Big families were crowed into small houses and most of them were made of wood and mud.

The reference is to the non-count building material.