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Universal design cost estimator


This tool helps you estimate how much it will cost to add universal design features during a new build or retrofit.

This tool estimates the costs of incorporating core universal design features for your particular situation. These costs are indicative but are based on many actual homes. Material and labour costs are included.

How to use the calculator

Use the drop-down menus to select:

  • the area(s) to upgrade
  • whether your house is a new build (still at the design stage) or a retrofit
  • the extent of key changes necessary - major = shifting at least one room, minor = shifting some walls but no rooms, minimal = strengthening walls in bathroom/toilet areas
  • floor area of the house
  • exterior features.

Click calculate for a total cost.

Universal design features

BRANZ conducted research to determine the likely costs of universal design for a range of variables, such as house size, new build versus retrofit and the extent of changes needed to bring the design up to a minimum level of performance.

The core features selected to make a home meet a minimum universal design level are based on accessibility, usability and inclusiveness:

  • All internal passageways are at least 1.05 m wide.
  • The largest bedroom on the primary living level is at least 4.4 x 3.15 m or 3.8 x 3.75 m.
  • The kitchen is at least 2.7 x 2.1 m to provide the required turning circle and distance between benches for a wheelchair.
  • The space for the bathroom and toilet is 2.95 x 2.1 m. If the bathroom and toilet are separate but next to each other, their combined size is used.
  • All internal and external doors have an 810 mm clear opening.
  • Bathroom and toilet walls are strengthened with extra dwangs for fittings such as grab rails.
  • All power sockets and light switches are between 0.9 m and 1.2 m above floor level.

Average costs (including materials and labour) for these adaptations were built up from a sample of 83 new and 112 existing house designs from previous BRANZ research.

The standards used to determine what the minimum features should be are NZS 4121:2001 Design for access and mobility: Buildings and associated facilities and the Lifemark Design Standards.

How much do universal design features cost?

  • For a 150–200 m² house, the cost of incorporating essential universal design features costs about $1,700 for a new house compared to $14,000 if that same house was retrofitted.
  • In most situations, the extra cost of incorporating universal design features into a new house will usually be less than 0.5% of its total build cost.
  • For internal changes, about 80% of new houses require no or minor changes to layout, doors and strengthening of bathroom fittings prior to construction. These adaptations add around $500 or less to the total new house cost.
  • For external changes, many new houses need wider parking areas and better access to the front door. These typically add another $1,200 to the house cost.
  • When changes are made to an existing house, the costs are typically $15,000 for internal work and another $7,000 for ramps and other external access features.

For more information on the background to costings, see SR263 Lifetime housing - the value case [PDF, 5MB].