How To Build A House That Can Expand In The Future

21 / 05 / 2023
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Custom Design



New Builds


When you are building new homes in Canterbury, you are most likely building within your budget means. If that is the case, you will no doubt have ideas in your mind about how you will expand the building in the future.

To achieve this in the future with your current house and land packages in Canterbury, you need to lay the foundations for that expansion – literally.

Here are some tips for building a smaller home that can expand in later years.


Think ahead five to ten years in the future and envisage the needs that your house will be expanding for. Design your home for that future need in order to get a feel for the footprint that your will need. The footprint is often bigger than you expected.

As you then trim back down to the current size, consider carefully what impact the expansion will have on the “starter” home. For example, what will the impact be on:

  • The site
  • The foundations
  • The structural systems
  • The electrical network
  • The services network

Plan your site with the expansion in mind and in keeping with building lines.


All buildings start at this point, so advise the engineers of the horizontal or vertical expansion you are considering so they can specify foundations accordingly for weight or spread. It is not cost-effective to modify old foundations but building larger or higher spec new foundations to accommodate future expansion is a cost saver.

If you are building a contemporary home with steel frames, then adjusting the steel system to support a vertical expansion is a cost-effective plan. The production and building costs will not adjust significantly. Masonry load-bearing walls, however, make expansions more expensive than steel frame extensions.


The interception and drainage plan for old and new roofs must be forward planned as this is possibly the hardest aspect to retrofit. Plan it out in full and then reverse back down to the starter home and ensure that the drainage is correctly planned. Flat roof designs are sometimes seen as easier to add onto but this is not always the case.


Consider the heating and cooling needs in the future home and plan how the piping, power and units for this will be accommodated. You will need to scale up the HVAC as the building grows, not install the future system now as this will cause performance and efficiency issues. Certain piping might be better installed in a bigger size from the beginning and your HVAC consultant can advise on this.

Fresh And Waste Water

The installation of your fresh and waste water supply piping is a good one to preplan for a future expansion. The site will have optimal run-off angles and council connection points that your network must fit into. Pre-planning will eliminate the need to relocate a sewer line or the laying of new freshwater mains and will save a significant amount of money.


Installing an electrical board, switch gear, conduits, lead wires and pull wires in anticipation of the future expansion is a good idea.

Don’t forget to also lay additional conduits from your smart home control room if you have one.


Planning for your home’s expansion is a smart idea as it will save you costs in the long run and add to the property value if you sell before expanding. Your forward planning will be rewarded in the sale price.

For more great ideas on house and land packages, call our team of experts today in Canterbury. We make the journey more pleasant. Contact Us Ph 022 657 7525