There are several different stump types you can use to restump your house. Steel, timber, or concrete are the more obvious ones. Piers and concrete part walls can also be used to provide footings for your elevated floor construction. A combination of materials can be used to restumping a building, although in most cases this is the norm sometimes a combination of materials may suite the construction better.
Timber is not so common any more it can be high maintenance and not very versatile for building in under your house. Timber stumps can have a lot of appeal under a semi low or low set house. Farmed and treated hardwood provides straight and long lasting stumps. It can be a good alternative under low block houses especially in areas of high rust or corrosion the stumps can be replaced a lot easier than steel or concrete. Steel has a concrete footing poured around the stump which can be extremely hard to remove without lifting the house. Concrete remains and full stumps are heavy and require mechanical means to remove them in many cases. Timber doesn’t rust so in these situation where they can be kept dry can last extended periods of time up to 30 years.
Concrete stumps are solid and have no movement, with a solid soul footing poured at their base on installation can be very strong and lasting. However depending on the installation can handle little to no sideways movement making them a poor choice in high wind and cyclone areas if they are not treated with care or provided with extensive bracing and certain engineering requirements are met.
The stumps as with timber usually start at 200mm x 200mm so they are bulky and don’t fit into wall framing readily unless non load bearing blocking, double brick or brick veneer insets are built between the stumps. Weight is an issue and handling expenses from freight to installation have an effect. Concrete stumps have steel reinforcing and this can rust if the concrete cracks for any reason. Concrete stumps have their place and look good as a standalone stump without structure attached or lining a driveway. As with timber they make a great solution when mixed with steel. The centre of the house can be supported on steel while a more bolder concrete stump can line the outside of a house.
Steel is by far the most versatile and has become more commonplace being the best choice in most situations. Provided galvanised steel is used, welds are painted and the installation is correct. Some attention to detail is applied where the concrete is mounded up around the stump. This is to allow moisture runoff on the top of the concrete where it meets the steel in the centre. Strength of the concrete and therefore it’s permeability to moisture is addressed. And other engineering considerations derived in the engineering and planning stages are met such as bracing on high-set buildings.
Steel stumps will last in most situations even in the damp and coastal conditions. Provided their installed correctly and made according to local engineering requirements. And they are very versatile in nature, the 75mm x 75mm construction allows them to easily be built into single leaf walls as with timber stud framing and also blocking or bricking. Steel posts allow for easy installation of beams. Removing certain stumps in the centre parts of the building opening up larger areas and making the space more usable.
Piers and part walls are suited to more specialised applications. Once again problem stricken areas may benefit from sections of strip footing and construction from the footing to the underneath of the house in whatever material is more suited. Whereas this becomes a relatively high cost it may not be excessive. If rust or corrosion under your house is an issue then reinforced concrete or brick walls may be the only solution for longevity.