If you receive a notice from your neighbour you should reply to it in writing within 14 days of receiving it
You do not need to appoint a professional adviser to respond to the notice on your behalf.
You can consent to or disagree with what is proposed. If you disagree with the proposal, and cannot resolve the matter between yourselves, the procedure enters into a dispute.
If you do not respond to a notice about an intended new wall built up to (but not astride) the line of junction, the work can commence after the one month notice period.
If you do not respond, in writing, within 14 days to a notice about an intended new wall built astride the line of junction (a party wall), the Building Owner must build the wall entirely on his own land. The work can commence after the one month notice period.
If you receive a notice about work to an existing party structure or a notice about excavations within 3 or 6 metres of your foundations, and you have not responded, in writing, within a period of 14 days from receipt of the notice, a dispute is deemed to have arisen. The dispute procedure then comes into play.
If you disagree with the work described in a notice under the Act it may be helpful to explain why. The Building Owner can then consider your objection and perhaps amend his proposal. An agreement might then be reached, without the need to use the formal dispute resolution procedure.