16 Oct Granny Flat Foundations – Waffle Pod Slab v Piers
Granny Flat Foundations – Waffle Pod Slab v Piers
Planning your granny flat budget and wondering whether it’s better to build on a waffle pod slab or concrete piers? We’re here to help. The best solution for you depends on your budget, location, and desires, so we’ll cover each. By the end of this blog, you’ll know which decision is best for you!
The two main options for a foundation are a slab or piers. Factors into the decision for each range from the terrain of your property to local legislation and everything in between. This decision cannot be taken lightly!
First, let’s cover what each is:
What is a Waffle Pod Slab?
A waffle pod slab is a slab made of separate sections that sits inside of a formwork perimeter. Reinforcement is added to the slab and then concrete is poured, creating a sturdy foundation that sits above the ground. It’s becoming more and more popular due to its cost, strength, and relative ease of construction (no labour intensive digging!).
What are Concrete Piers
Just like piers down on the water, concrete piers are like sturdy legs that stick far above ground on which your home is situated. Piers are surface-level structures (meaning they aren’t dug deep into the ground), so this means they are meant mainly to raise the elevation of a structure and not stabilize it relative to the ground (unsturdy soil will still require work).
Considerations for choosing a foundation
When deciding whether or not to use waffle pod slabs vs concrete piers, you should consider:
- The terrain: The terrain will be deciding factor #1. If your land is sloped, then piers may be best so that you can avoid costly excavation projects. If the land is flat, then a slab is a simple and cost-effective option.
- Local legislation: Grannies are subject to a set of laws in each jurisdiction. For example, NSW penalizes buildings of excessive height by increasing the minimum distance to the boundaries of your property. This might change the dimensions of the entire project.
- Overall costs: Costs will vary based on terrain, but slabs are usually cheaper to build on than piers unless there are mitigating circumstances. If you have sloped terrain that would require retaining walls and excavation, then piers are cheaper. If you have relatively flat land, then a slab is the way to go.
- Flooding: Is your locale prone to flooding? If so, it may be mandatory to build on piers. If there is regular flooding or your property is in the path of floodwaters, you have no choice. You won’t be able to fill in the gaps between perimeter piers either, as to leave room for the water to flow.
- Elderly/Handicapped access: Building on piers will decrease accessibility. It will require you to build stairs or ramps.
This is far from an exhaustive list. Only certified professionals will really know if you need to build on piers or if you should just stick with a waffle pod. In our experience, slab is the most common method due to its simplicity and cost.
Want to know more? Contact Lounging Lizards today for a free quote!