Base Stage
Stage 1: BASE STAGE
Inspection:
Inspection of the base stage is the first and very important step to ensuring that you home is well constructed. This is doubly true with slab-on-ground constructions.
The design of the foundations and footings can vary considerably form home to home. Factors such as the type of soil the dwelling is being construction on and the design of the home have a bearing on the choice and design of the base.
A typical slab-on-ground base may for example have a number of engineered features to deal with the natural movement in the soils. the more reactive the soil type the more extensive the engineering of the slab. Thickening beams, piles, and waffle design may be employed to provide a stable foundation for your home.
The design and engineering of the base is one thing but it is just as important that the base be constructed correctly.
The ABIS Base Stage Inspection is conducted before any concrete is poured in order to inspect items such as under slab waterproofing, placement of reinforcing steel, and termite protection befor the are hidden by the concrete.
What Is Inspected?
This depends on the design of the slab but for Slab-On-Ground constructions the following are checked:-
- The site identified according to job sheet by means of Builders sign or survey pegs. Site conditions including access, driveway slope, retaining walls and fences recorded for reporting.
- Orientation of the building in relation to the access road recorded. Weather conditions and site gradient noted.
- Check the position of the external wall location in relation with the footings and the inclusion of reinforcement starter bars tied to the slab mesh. The steel visually checked for clearance from the base (40mm) and from the slab finish (no less than 20mm)
- Under slab services checked for defects, and quality of materials used. Installation of stormwater pipe system noted. Under slab services include drainage, plumbing, electrical, phone/data.
- Termite control noted including the type and location of barriers ie, to drainage pipes.
- Record the location of the electrical meter box including the provision of a safety switch.
- The site checked for possible termite nesting sites and other conditions conducive to termite activity.
- Visually check that the site is clear of building rubbish and materials are adequately stored in an appropriate manor.
1. Site Conditions
- Site Gradient
- Cut/Cut & Fill/Fill
- General Soil Type
- Orientation to road
- Weather: Raining/After rain/Dry
- Surface drainage
- Subsidence
- Seepage
- Retaining Walls & location
2. Site Improvements/Conditions
- Landscaping
- Driveways/access/slope
- Crossover
- Paving
- Fencing
- Builders sign/site identification
- Storm water pipes
3. Floor Structure
- Footings
- Formwork/brick base
- Damp-proofing membrane
- Steel placement and fixing
- Thickening beams/piers
- Sub base compaction
- Floors below ground level
- Suspended floors
4. Under slab Services
- Sewage pipes
- Plumbing
- Electrical
- Phone/data cable
- Termite control
Some notes on Foundations:
A house needs a foundation to shoulder its considerable weight, provide a flat and level base for construction and separate wood-based aterials from contact with ground to prevent decay and undetected termite infestation. The most common material for foundations is concrete.
Most houses have a raised, perimeter foundation that supports floors and load-bearing walls. Some are built on a flat, concrete slab that provides both a base for the structure and the bottom floor of the house. Older homes have ended to rest on a series of concrete piers. Other houses utilise all these methods for different portions of the house. Houses with perimeter foundations for example, often have post-and-pier supports beneath a beam that runs under a load bearing wall along the middle of the house.
The base of a foundation or footing is generally wider than the foundation wall and is designed to distribute the house's weight to prevent future settling or movement.
There are three types of conventional concrete foundations: poured concrete, concrete block and post-and-pier all regulated by Building Codes. A poured-concrete foundation may be a raised perimeter foundation, a flat slab, a ombination of the two or a monolithic slab where footings, foundation and slab are a single, integral unit.
A conventional perimeter foundation has a poured concrete wall supported by a poured concrete footing. Both are strengthened by steel reinforcing rods and used in connection with both raised floors and slabs.
