It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "When the neighbour of one of you asks him about fixing a peg in his wall, he should not prevent him."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلح / 11379