。
Wooden houses catch fire easily.
Literal
Wood-built houses [topic-は] fire [subject-が] attach-easy.
火がつく ('fire attaches / fire catches') is the standard collocation for 'to catch fire' — using つく ('to attach, to stick'), the same verb as 嘘をつく. Adding ~やすい gives 'easy for fire to catch.' Note the double-subject feel: 木造家屋 is the topic, 火 is the subject of 'catch.'