It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When someone asks his neighbour for permission to place a beam on his wall, let him not refuse him."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب إحياء الموات / 11880