Designing and building

With the correct design, materials and construction you can build a home that won't leak and that will be comfortable and durable.

Designing and building

What do you need to consider before you design and build your home?

The site, style and design of your home all affect its ability to withstand the weather. If you consider these when designing and building a new home you will reduce your chances of getting a leaky home.

Consider the site
Your choice of site will be strongly influenced by location, outlook, price and other factors important to you. When choosing the site consider how the orientation and exposure will affect your new home’s ability to resist the weather. One of the main ways to make the most of your site will be to orient the house and certain rooms to take best advantage of the sun and views.

The orientation, house design and landscaping can also make a big difference in how the home deals with strong winds and rain. This has a big impact on how livable and weather resistant your home is.

Consider the style
The style of home is also important for protection from leaking. The house design will have a major influence on the risk score your new home will earn when your designer considers the detailing. The factors that will influence the weathertightness risk are:

Wind zone.
Number of storeys.
Roof/wall intersection design.
Eaves width.
Envelope complexity.
Deck design.

While you can’t change your wind zone, the other factors are under the control of you and your designer. High-risk scores will require additional consideration and more expensive solutions to the junctions between claddings, windows, doors, roofs and other features. Working with your designer on the initial design can greatly reduce the risk of a leaky home later on.

How much do you need to know?
Your designer and builder should know how to build a home that will not leak. This is when hiring the right people becomes crucial. Talk to your designer and builder and gauge their understanding of designing and building for weathertightness. Your designer should be able to advise you on the best options and enable you to understand what is required and why. Also see Weathertight design principles.

Building consent
The Building Consent Authority or BCA (usually your local council) will require a high level of detail in your consent application, especially if specific design is required. Specific design can be required on very exposed sites, or where the weathertightness risk score is over 20.

The level of detail now required for a building consent – which will indicate if an Acceptable or Alternative Solution is used – means that a partial design service with your designer is less feasible. From 2010 certain building and design work will have to be carried out or supervised by a licensed building practitioner (LBP). This means designers will be required to be licensed to work on your project by 2010. See Licensing building practitioners for more information

Assurances for you
To reassure you of the quality of the design and construction of your new home you can ask that your designer provide you with:

Evidence that they are a licensed building practitioner (ask to see their ID card or check the Register).
Proof that your builder is a member of the Registered Master Builders’ Federation or Certified Builders’ Association of New Zealand. See Builders’ guarantees for more information.
Proof that cladding materials and other systems used in your home either have a current BRANZ Appraisal Certificate or other evidence of quality and performance. See Certification of products and building methods for more.
Guarantees for roofing, claddings and other components as installed.

You should also ensure that the contract allows for final payment only after a code compliance certificate is issued by the BCA.

While building

Your designer should keep you informed of progress as work on your home gets underway. It is very important that once the building consent is issued any changes to materials or any aspects of the design is approved by the BCA. This may require an additional consent for the altered work.

Alteration of the design or substitution of materials without additional consent is likely to prevent a code compliance certificate (CCC) being issued, as this certifies that the building has been constructed in accordance with the building consent. See Construction phase for more information.

At completion

The designer or project manager should inform you when to apply for the CCC and energy work certificate (for electrical and gas installations). This will be at the completion of all work done in accordance with the building consent.

You should also ask your designer about the maintenance requirements for your new home. The designer will be able to give you guidance on normal maintenance you need to carry out to ensure the building continues to perform throughout its life.

Also ask if there is any specific maintenance or checks you should know about with the wall claddings, for example, checking membrane joints, cleaning internal gutters or checking joints in claddings. See Final stages for more information.