New Building Home Inspection
Here are the standards for progress inspections (quality control) of new building work. Municipal and NHBRC inspectors provide limited statutory inspections largely as regards compliance.
HouseCheck fees for progress inspections of new building work are quoted in accordance with the number of such inspections required by the client.
HouseCheck also offers “Snag inspections” of new building work prior to handover from the builder to the new owner.
- All new building work should be compliant with the building plans and drawings approved by the local authority;
- Positioned on a site (which has been identified by the location of the boundary pegs) in accordance with the plan approval;
- Levels, dimensions and squareness of corners must be checked.
- Datums for levels must be established so that the finished floor level is at least 150 mm higher than the finished ground level.
- All the rooms on the same floor level should be set out at the same time so that dimensions and squareness can be checked.
- The accuracy of the setting-out should be checked: The distances of the proposed structure from site boundaries and adjacent structures must be verified.
- Diagonal checks and the 3.4.5 method are to be used to check for accuracy of setting out and measurements.
- All building work and building materials must be in accordance with the approved drawings and be compliant with the National Building Regulations by:
- Meeting the minimum deemed-to-satisfy standards of SANS 10400 and other related national standards, or;
- Through rational design by an approved competent person.
The site should be secured and managed in compliance with the safety standards of the Construction Regulations 2014.
Site preparation inspections
- The site has been cleaned and graded so that stormwater flows away from the structures to be built.
- The site should be cleared and graded for a distance at least 1,5m from the external walls.
- Sites to receive slab-on-the-ground (raft) foundations must be leveled and compacted. The bases of edge beams of a raft slab may not be sloped not more than 1:10.
- Retaining walls should be installed where necessary to protect the structures and to prevent erosion.
- In areas where termites are active the local authority will require soil poisoning for the site.
Excavations, fill and foundations inspections
- The foundations must be designed in accordance with the geotechnical report which predicts potential soil movement on the site.
- If strip footings are required the bottoms of the trenches are cut vertically to firm virgin ground, the bottoms are horizontal, correctly stepped and the top of the trenches are sloped away from the trenches.
- In stable soil conditions, the minimum width of strip foundations must be 500mm for external walls and 400mm for internal walls (for a house with a tiled or sheeted roof).
- The minimum depth of the foundation must be 200mm.
- The strength of the concrete used for the strip footing should be 20 MPa or better.
- Before the pouring of the concrete, the inspector should check:
Levels of the formwork.
- Thickness of the concrete in the strip footings/floor slab/raft foundation. Measurements of the foundation/floor slab. Check that the steel reinforcement or steel mesh is as specified and has been placed correctly, separated from the soil and with a minimum cover of 50 mm.
- Concrete should be placed as soon as possible after the excavation has been completed and inspected.
- Concrete should never be re-wetted on site.
- Concrete pours should be planned so that practical concreting is carried out in one continuous operation so that there are no cold joints in the concrete.
- Compaction of the concrete: Concrete should be compacted by mechanical vibrations or by means of tamping, spading, rodding or forking in such a manner that the concrete is thoroughly worked against the formwork and around the reinforcement and other embedded items without displacing them, so as to ensure that the concrete is free from honeycombing and planes of weakness. Inadequate compaction can seriously affect the quality of the concrete. The concrete may be assumed to be fully compacted when air bubbles cease to rise to the surface of the concrete in the vicinity of the vibrator.
- After pouring the concrete, the inspector should check:
- The finishing of the surface of the slab.
- Finished concrete should have a neat, smooth, even and uniform finish free from any honeycombing. A minimum, wooden float finish is required.
- If raft foundations are required, the raft (stiffened slab-on-the-ground) must be constructed according to the design prepared and certified by a structural engineer.
- The maximum height of clean fill beneath slabs must not exceed 400 mm, unless certified by a structural engineer. Fill should be compacted in layers.
- All foundation walls must be at least as thick as the wall carried by the foundation walls.
- Foundation walls higher than 1,5 m must be certified by a structural engineer.
Damp proofing inspections
- Damp proof membrane (DPM) below slabs: A 250 micron thick DPM of plastic must be laid above the compacted fill and turned up around the perimeter of the slab by at least the thickness of the slab.
- Damp proof course (DPC) below external walls: A plastic DPC must be installed between the foundation/foundation plinth and the exterior walls. The DPC must extend beyond the wall or the plastered surface to prevent moisture wicking up from the ground into the walls.
- In any masonry wall a damp-proof course shall be installed at the level of top of a concrete floor slab resting on the ground.
- No horizontal damp proof course shall be installed less than 150 mm above the level of the adjacent finished ground.
- Transverse joints in the damp-proof course shall be overlapped to a minimum distance equal to the full thickness of the wall or the leaf, as the case may be.
- Damp-proof courses shall be laid to the full thickness of the wall and lapped at least 150 mm at all joints in the running length.
Masonry wall inspections
- Masonry walls must be plumb and square. Check the plumbness of walls and the levels of masonry courses regularly.
- Masonry walls must be laid at the centre of the strip footings.
- Not more than 1,5 m of wall height should be built in a day. This is to allow the mortar to cure before it is subjected to an excessive load.
- Brick walls should be raked back during the building process. “Toothing” is not permitted.
- Dimensions (thickness and height) must comply with the approved drawings.
- Masonry units (bricks and blocks) must be installed in compliance with SANS `10400-M.
- Brickforce, wall ties, lintels and rod reinforcement must be compliant.
- Cavity walls should be flushed clean at the end of each day’s work.
- Roof anchors should be built into the walls in compliance with SANS 10400-L.
- In the case of heavy roof coverings (tiles or slates) the roof anchor must extend into the wall to a depth of at least 300 mm.
- In the case of light sheeted roof coverings, roof anchors must extend at least 600 mm into the wall.
Door and window frame inspections:
- Door and window frames should be set in position, securely braced and strutted and built in as the work proceeds. Inspectors should verify the square in the corners of the frames and the vertical plumb in both directions at the moment of the setting, as well as the right fixing of such frames to the wall and the correct placement taking into account the direction towards the door will be opened.
- Door frames should be protected from wheelbarrow damage during building operations. The threshold brace at the base of the door frames should only be cut once the doorframe has been fully installed to prevent wheelbarrows and pedestrian traffic damaging the door frame.
- Door thresholds opening onto patios or balconies should have a weatherstep of at least 50 mm.
- Door and window frames which are to be built in should be set square and plumb in the wall reveals in accordance with the designer’s specifications.
- Window sills
- Damp-proof courses must be placed under window sills.
- Window sills must be installed to guide water running down the window away from the wall. Sills must extend at least 15mm out from the wall, be sloped down and have damp proofing installed. Installation of a drip on the underside of the sill will prevent water from running back against the wall.
Stairways and balustrades inspections
- The building inspector should check compliance with SANS 10400-M:
- Minimum balustrade height: 1 m.
- Maximum openings in the vertical balusters ( residential only): 100 mm.
- Minimum headroom: 2.1 m.
- Maximum rise to landing: 3 m.
- Minimum tread: 250 mm.
- Maximum riser: 200 mm.
- Maximum 3 winders.
Garage joined to residence – fire safety inspection
- Where a garage is part of a residential structure then the following applies to minimise fire risk:
- Solid brick fire wall from the floor of the garage to the underside of the roof covering.
- Fire resistant self-closing door – minimum fire resistance 30 minutes.
- Garage floor must be a minimum of 10 mm below the floor level of habitable rooms.
- The tops of the walls should be level to accommodate the installation of the wall plate.
- Galvanized steel trap anchors must be taken up over the top of the rafter or tie beam, bent down on the other side and nailed down from both sides, or galvanized roof ties shall be made up of two strands of wire, which shall be taken up on either side of the rafter or tie beam, twisted together so as to have no slack, but not so as to overstrain the wire, and the free ends then nailed down to prevent untwisting.
- The roof trusses should be erected plumb with spacing, bracing and fixings as specified by the roof designer. Truss, rafter and purlin/batten spacing for different roof coverings must be in accordance with the manufacturer’s instructions/certificate or as directed by a competent person.
- Battens and purling must be continuous over at least three rafters and must be fixed to every rafter that they cross.
- The support structure for any hot water heater tank, which is to be installed either in the roof cavity or on top of the roof, should be designed by a competent person in accordance with SANS 10400.
- Roof covering, waterproofing and roof drainage
- The roof covering, flashing and waterproofing and rain goods (gutters and downpipes) should be installed in accordance with the manufacturer’s specifications.
- Roof projections and chimneys must be compliant and waterproof.
- Check that the tops of parapet walls and chimney crowns are waterproofed and that all intersections between roof planes and walls have been properly flashed (waterproofed).
Stormwater management inspection
- The building inspector should evaluate the effectiveness of stormwater management systems by asking: “Where will the water go when it rains heavily? The inspector should evaluate:
- The slope of the ground in relation to the structures;
- The size and placement of drainage systems;
- Locate potential areas of ponding or flooding;
- Examine how the roof drainage system (downpipes) links into the ground stormwater management system.
Sewerage drainage installation inspections
- Here is a basic inspection checklist for drains:
- Is the connection point correct and as per the approved plan?
- Is the drainage layout as per the approved plan?
- Is there a minimum of one overflow gully on the drain system?
- Have rodding eyes been provided in terms of the approved plan and at least every 25,0 m or where there is a change in direction of the drain which is 90° or more.
- Are manholes provided, maximum 50 m apart.
- Anchor Blocks provided where fall exceeds 1:5.
- Diameter of drainage and waste pipes in order, and SABS approved.
- Invert level and gradients of drains in order.
- Is the soil cover of the drain at least 450 mm?
- Have water traps been fitted to all sanitary fixtures?
- Where fixtures are more than 3,0m from a ventilated drain has a stub-stack vent been provided?
- If the drain runs below a building is the drain:
- Encased in concrete.
- With no bends or connections beneath the slab.
- Septic tanks and French drains
- Septic tanks must be sited:
- Minimum 20 m from a water source
- Minimum 2 m from structures and from the boundary
- French drains:
- Has a percolation test been carried out?
- Is the French drain a minimum of 3 m from structures and from the boundary?
Compliance of installations
The building inspector controlling the quality of new building work should be able to rely on the certification of relevant specialists as regards installations such as: Electrical; plumbing; waste and soil water disposal; fire, gas and electric fence installations.
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