This sentence stands for the imperfect tense. This tense is used to talk about past actions, conditions, or events that occurred regularly or frequently or that were in progress in a moment in the past. Había is the conjugation of the verb haber for the third person singular and era is the conjugation of the verb ser for the same person as well. Therefore:
<em>No </em><em>había</em><em> mucho espacio; la casa no </em><em>era</em><em> muy grande.</em>