I have a house on stumps in Brisbane that is built on highly reactive soil (H2 slab required if using a slab) and is approximately 12 months old.
I am about to start planning my landscaping and want to make sure that I do everything possible to prevent potential issues to the house from ground movement (i.e. ‘slab’ heave, without the slab).
In summary, the considerations are as follows:
- Eastern side – back yard. Planning to turf majority of yard. There is a shed in one corner and plan to grow lillypillies along back fence to height of ~2.5m for privacy.
- Western side – front yard. Planning to turf majority of yard.
- Northern side – approximately 2m space between house and 2m tall fence. This space is used as a walkway for bin, hanging up washing etc. Sunlight is somewhat limited due to fence height, though current grass manages to cover majority of ground. Some moss on ground during winter due to limited sunlight. My initial preference is to turf this area.
- Southern side – approximately 3.5m space between house and 1.8m tall fence. Space is designed for vehicle access when required (very rare). Due to positioning of the house, sunlight is also somewhat limited however there no moss growing on this side. My initial preference is to also turf this area.
- I note the requirement in my soil report that recommends a 50mm fall away from the house over the first metre. I also note the standard recommendation for a 1m concrete perimeter around the perimeter of the house (if relevant, the house also has 0.6m eaves).
With reference to these considerations, I want to figure out a recommended approach to landscaping. My questions therefore are:
- In terms of preventing ground movement, is it likely to be sufficient to turf all areas, with the ground around the house landscaped to fall away from the house?
- If the above approach is not recommended, should I be installing a concrete perimeter around the whole house for protection against ground movement, or due to being a pole house is this need reduced? What about pebbles or something different to concrete?
If the above approach is not recommended:
- If I only did a perimeter on the northern and southern sides and turfed up to the house on the eastern and western sides (i.e. front and back yards) , is it possible that this could create a differential between the northern/southern and eastern/western sides and actually increase the possibility of movement?
- If I end up deciding that the northern and southern sides are going to be too hard to grow consistent turf on, what are my other options? My preference would probably be not to turf the whole area (especially the larger southern side), plus that would mean looking at more drainage solutions etc. What other options are there is turfing isn’t feasible?