How To Add Value With A House Extension



Some homes require a renovation due to a growing family or the home is ready to be rejuvenated or given a refresh. In some cases the only option to add more room by adding a house extension.

Either way, adding more space will add value to your home.

The team at Style Plus Renovations Auckland look at 5 key design aspects of building a house extension:

  • Planning your extension.
  • Open plan living & indoor | outdoor flow.
  • Which extension style suits my house?
  • Windows & doors.
  • Cladding & painting.
House extension renovation


If you are planning a house extension, great! However, you may have no idea where to start and what to consider?

To help you along the way, here are a couple of typical questions that an architect or project consultant would ask during the design phase of a project:

  • Is your new extension going to be a single or double storey extension?
  • What type of cladding are you thinking of using? Weatherboards?
  • Will your extension have sliding or bi-fold external doors?
  • Are you looking at timber or aluminium joinery?
  • What about installing Velux skylights to bring in more natural light?
  • Will the extension include an additional bathroom or will it just extend your current living space?
  • Do you have a copy of your council property file?


When planning your single level house extension consider the design elements of indoor | outdoor flow. Including this in the design will provide a natural, social, open space.

In general open plan spaces that have the indoor | outdoor flow tend to be designed as a living | kitchen space. At Style Plus our clients love the design of the kitchen and dining spaces just a short walk away from your outdoor living space.


Deciding the style of your new house extension is probably the most important design planning decision you will make.

The style you choose will dictate the build cost and appearance. In general, it pays to ensure you are happy with the concept design and it is within your budget. It also has the consequence of increasing the value and desirability of the property.


Installing large doors from the living spaces to the deck space is a good way to introduce the indoor | outdoor flow. Ranchslider | sliding doors are an excellent option to open up a living space.

If the new house extension includes new window joinery, there are a few important factors to consider that includes aesthetics, cost, natural light, thermal comfort and ventilation.

For older homes that are weatherboard clad and have timber joinery, there are pros and cons whether to install timber or aluminium joinery.

For timber joinery, there is the aesthetic appeal of the weatherboard and timber joinery combination. Timber can also be energy efficient as it can be an excellent natural thermal dampener. However, maintenance is higher for timber joinery.

With aluminium joinery, the overall maintenance is low and it can be powder coated to many colours to highlight the feature of the windows | doors. Aluminium is also structurally stronger especially if your home is located in a high wind zone.

  • For more information regarding aluminium joinery check out Fairview.
  • For timber joinery, check out Dando.


When the time comes to extend your home you will have the option to keep all of the original cladding on your house and install the same style of cladding to your new extension. If done well, the appearance of the new extension will blend into the house seamlessly.

The choice of weatherboards comes in a variety of materials – from the traditional timber, to fibre-cement weatherboard and composite materials like aluminium or UPVC.

In New Zealand, timber is the classic choice for weatherboards. Timber weatherboards are available in a range of profiles and timber species. Main timber species are:

  • Radiata pine,
  • Accoya wood and
  • Western red cedar.

They can be installed by hanging planks horizontally (traditional bevel-back look) or vertically, ‘shiplapped’ to suit the requirements of the new home extension.

Radiata pine is the most commonly available timber in New Zealand. It is used for a wide variety of purposes because of its affordability and quick maturity. A pale coloured timber with wide distinguishable growth rings. The timber is generally quite uniform in grain structure. This timber is not naturally durable. However, with preservative treatment the timber can be as durable as most durable hardwoods.

The cost of pre-primed pine weatherboard, 150mm X 25mm bevel back linear meter, is around $10. However, building companies often use a square metre rate to attract customers. This estimation method can provide a high level cost. However, this method can also be misleading as it does not take into consideration, for example, the shape of the house or access to the house.

To obtain a better cost estimate, the job would require a detailed take-off from the plans and specifications designed for the project. Estimators can also complete take-offs by visiting existing buildings and construction sites.

Accoya wood is comparable or better than the durability of hardwoods such as Jarrah, Rosewood, and Teak. Recent tests show that Accoya wood is perfect for coated cladding where reduced maintenance is required, even with wood stains and dark colours. The acetylation process makes pine super durable, super stable and retains all the strength of pine.

The cost of Accoya weatherboard, 150mm X 25mm bevel back per linear meter, is around $32.

Western red cedar is a light timber with a distinctive odour. It is non-resinous and straight-grained, with obvious growth rings. This timber adopts a uniform reddish-brown colour once dried. However, after long exposure wood becomes silver grey. This timber stains and paints well.

The cost of cedar weatherboard – vertical shiplap 150mm X 22mm per linear meter, is around $21.

A number of companies supply pre-primed timber weatherboards. Primers range from water-based, solvent-based, dual coats and some are applied with UV curing technology.

Tip: Weatherboards should only be painted when dry and the board is near equilibrium moisture content. As a minimum two top coats of premium low gloss acrylic should be applied.

Resene Paint Systems

Dulux Paint Systems

Recent Design & Build Work

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