What is a design certifier?

How it works in Ireland

The design certifier answers one question: does the design, as drawn and specified, comply with the Building Regulations? They sign a Certificate of Compliance (Design) and the builder’s and assigned certifier’s paperwork refers to the same drawings. That certificate is one of the documents filed with the commencement notice, together with the preliminary inspection plan, the assigned certifier’s appointment and undertaking, and the builder’s undertaking.

Planning permission is a different test. Permission says whether you may build what is shown; the design certificate says the design can be built in a way that satisfies Parts A to M of the Building Regulations, from structure and fire to drainage, energy and access. A design that has permission can still need changes to be certified.

The design is certified as it stands at commencement. If you change it afterwards, ask the design certifier whether the change needs a revised certificate or notice, and tell your assigned certifier so the inspection plan matches.

For most self-builders the design certifier is the architect or engineer who drew the plans, so agree in the appointment letter that they will sign the design certificate and what it costs. A person who did not prepare the design can still certify, but must be eligible and willing to take responsibility for it.

A common mistake

Assuming that the design certificate is a formality. A certifier signs only when the drawings and specification are complete enough to certify, so a house still being redesigned cannot be filed. Settle the details that affect structure, fire, insulation and wastewater before the date you want to start.