Does The House Need Repiling? Repiling NZ Style…
What are Piles?
Piles are wooden or concrete posts under a house that form the foundations and are what many New Zealand houses sit on. The job of the piles is to distribute the weight of the house evenly across the soil underneath, and the house construction distributes the house weight as evenly as possible over the piles, ensuring the house stands straight and square.
Over time piles can rot away, causing them to fail, uneven distribution of house weight over piles can cause uneven settling, or movement of the ground under and around piles can cause piles to move.
Has the house been repiled?
If the house was built in an era that used totara piles, an a examination of the piles under the house will soon determine if repiling has happened. New piles are either concrete or tanalised (H5) pine and are easy to spot.
Make sure to check out that all the piles have been replaced. It is quite common to see that only a few piles are new, often these are the piles around the edge of the house.
Sometimes all the piles move, but more often different piles move to different extents. This causes the house to twist, bow, and crack, resulting in damage. The piles may have stopped moving, or may be continuing to move - this all depends on the cause of the movement. To halt ongoing damage, re-piling is necessary. If you are planning renovations, it pays to start with firm foundations or you are going to end up with an inferior result.
Repiling involves digging new piles down to a firm base and attempting to re-align the house on this new foundation. Sometimes it is obvious that repiling work is necessary. You may find yourself walking up hill and down around a house! Usually it is a lot more subtle.
To establish if the piles are a problem and to what extent, you will need to ask the experts. A house inspector is a good start. Make sure you get a good idea as to what is caused the need for repiling – it this likely to be an ongoing issue? i.e. poor soil, ongoing subsidence, risk of landslide. Can the cause be fixed? i.e. leaking pipe, drainage issues causing water to run under the house.
Repiling - The process
Repiling is a major job and different repilers repile use different methods - some cut holes in the floor to access under the house and some lift the entire house up. The technique used depends on a variety of factors with access being a big deciding factor and personal preference and tools and equipment available to the repiler having an influence too.
I am repiling - What else can I do?
Repiling opens a lot of opportunities to do other things to a house, it can be moved, lifted up and another level added underneath, or shifted somewhere else completely! The access that is gained under the house is also an opportunity to do things underneath that in usual circumstances are quite difficult - like underfloor insulation and working with the plumbing and electrical systems.
Repiling requires a building permit - other additions and changes to the house can be added to the same permit so it pays to plan in advance exactly what you want to do with a house before you repile so all your permissions can be gained at the same time - saving money - and also allowing you to organise access under the house for other works while the repiling is happening.
How much for a repile?
If you need to repile get a repiler in for a quote. Re-piling costs vary hugely and depend on many. Repiling costs start at around $12,000 - 15,000 (for a very small house, on the flat with fantastic access) and quickly climb when you start getting into soft soils, erosion problems and difficult access.