Introduction
Building a deck is one of New Zealand's most popular outdoor projects, and for good reason. A well-designed deck can add significant value to a property, provide a seamless transition between indoors and outdoors, and create a perfect space for entertaining and relaxation. However, with so many options available, it can be overwhelming to decide on the right materials, design, and construction method. This guide covers everything you need to know about building a deck in NZ, from consent rules and timber selection to construction and maintenance. Whether you're a seasoned DIY enthusiast or a homeowner looking to hire a professional, this guide will help you navigate the decision-making process and ensure your deck is safe, durable, and meets your needs.
Do you need building consent for a deck?
Under Schedule 1 of the Building Act 2004, decks that are less than 1.5m above ground level generally do not require building consent. However, there are some important exceptions to consider. If your deck is attached to a building that has already been consented, and the attachment affects the weathertightness of the building, you will need to obtain consent. Additionally, if your deck includes a significant structural element, such as a beam or a post, you may need to obtain consent. It's also important to check your district plan, as some councils have specific setback rules or requirements for pool fencing if your deck is near a pool. Balustrade height is also a critical consideration, with a minimum height of 1m required where the fall from the deck exceeds 1m.
Before starting your project, it's a good idea to call your local council's duty planner for free advice on whether you need consent. You can also visit our website at tradietools.nz and check out our guide to building work without consent in NZ for more information.
Timber selection
When it comes to choosing the right timber for your deck, there are several options to consider. Here are some of the most popular types of timber used for decking in NZ:
- Pine (treated): H3.2 treated pine is suitable for above-ground decking, while H4 treated pine is required for posts that will be in contact with the ground. Kiln-dried pine is a good option for decking, as it is less prone to cupping and warping. The cost of pine decking ranges from $30 to $60 per linear metre.
- Hardwood (kwila/merbau, vitex): Hardwood decking offers a beautiful finish and is more durable than pine. However, it is also more expensive, with prices ranging from $60 to $120 per linear metre.
- Composite decking (Trex, Futurewood, EasyDek): Composite decking is a low-maintenance option that is resistant to rot, decay, and insect damage. It is also splinter-free and comes with a 25-year warranty. The cost of composite decking ranges from $100 to $200 per square metre.
Here is a comparison table of the different types of decking materials:
| Material | Cost | Maintenance | Lifespan | Aesthetics |
|---|---|---|---|---|
| Pine | $30-$60/m | Medium | 10-15 years | Good |
| Hardwood | $60-$120/m | Low | 20-30 years | Excellent |
| Composite | $100-$200/m² | Low | 25 years | Good |
Design considerations
When designing your deck, there are several key considerations to keep in mind. These include:
- Board spacing: The spacing between deck boards will depend on the type of material you are using. For timber decking, a spacing of 5mm is typical, while composite decking should be spaced according to the manufacturer's specifications.
- Joist spacing: The spacing between joists will depend on the size of the decking boards and the load that the deck will be carrying. A typical spacing for 90mm decking boards is 450mm centres.
- Post sizing: The size of the posts will depend on the height and load of the deck. A minimum post size of 90x90mm is recommended.
- Ledger attachment: The ledger is the horizontal beam that attaches the deck to the house. It is critical to ensure that the ledger is properly attached to the house to maintain weathertightness.
- Drainage falls: The deck should be designed to drain water away from the house, with a minimum fall of 1:100.
Step-by-step construction overview
Here is a step-by-step overview of the construction process:
- Layout and posts: Mark out the location of the deck and dig holes for the posts. Concrete the posts into place and allow to set.
- Bearer installation: Install the bearers, which are the horizontal beams that support the joists.
- Joist frame: Install the joist frame, which consists of the joists and the ledger.
- Decking boards: Install the decking boards, starting from the outside edge of the deck and working your way inwards.
- Balustrades: If required, install the balustrades, which are the railings that surround the deck.
- Finishing: Finish the deck by applying a coat of oil or paint to protect the timber and enhance the appearance.
Balustrade requirements
Balustrades are required for decks that are more than 1m above the adjacent ground level. The minimum height of the balustrade is 1m, and the openings between the balusters should not be more than 100mm to prevent child safety issues. Balustrades can be DIY or purchased as kit systems.
Cost breakdown
The cost of building a deck will depend on the size of the deck, the materials used, and whether you choose to DIY or hire a professional. Here are some estimated costs for a 20m² deck:
- Pine deck (materials only): $3,000-$6,000
- Pine deck (professionally built): $8,000-$15,000
- Composite deck (materials only): $5,000-$9,000
- Composite deck (professionally built): $12,000-$22,000
It's worth noting that there can be regional variations in cost, with Auckland typically being around 20% more expensive than other parts of the country.
Deck maintenance
The maintenance requirements for your deck will depend on the type of material you have used. Here are some general guidelines:
- Pine: Re-oil or paint every 2-3 years to protect the timber and maintain the appearance.
- Hardwood: Oil annually for the first 2 years, then as needed to maintain the appearance and protect the timber.
- Composite: Wash annually with a mild detergent to keep the deck clean and free of debris. No oiling is required.
To help you manage your deck maintenance and other trade-related tasks, consider using a job management tool like Fergus or Tradify. These tools can help you stay organised and on top of your workload, and can even integrate with accounting software like Xero to make invoicing and payment tracking easier.
FAQ
Here are some frequently asked questions about building a deck in NZ:
- How close to the boundary can I build a deck in NZ?: The distance you can build a deck from the boundary will depend on your local council's rules and regulations. It's best to check with your council before starting your project.
- Does a deck add value to a NZ home?: Yes, a well-designed and well-built deck can add significant value to a property.
- Can I build a deck myself?: Yes, you can build a deck yourself, but it's essential to ensure that you have the necessary skills and knowledge to do the job safely and correctly.
- What's the best decking material for NZ?: The best decking material for NZ will depend on your budget, lifestyle, and personal preferences. Consider factors like durability, maintenance, and aesthetics when making your decision.
- Do I need a balustrade on my deck?: If your deck is more than 1m above the adjacent ground level, you will need to install a balustrade to ensure safety.
Conclusion
Building a deck can be a rewarding and enjoyable project, but it's essential to do your research and plan carefully to ensure that your deck is safe, durable, and meets your needs. By following the guidelines and tips outlined in this article, you can create a beautiful and functional outdoor space that will enhance your lifestyle and add value to your property. For more information and to get started on your deck building project, visit our website at tradietools.nz and check out our deck calculator to get an estimate of the costs involved. You can also find a list of qualified builders in your area by visiting our builders page. Happy building!