Design defects with new homes,

New homes with design defects. Identified by Peter Weddell, owner/operator of Qld Home Buyers Inspection Service and Queensland Building Inspection Service, QBIS.

Well designed and practically built new homes can avoid faults from developing in the short and long term.

New homes and design defects

Design fault in new homes:

  • Timber mouldings fitted around exterior of windows without flashing protection
  • No flashing to sill of window.
  • Sill timber with no slope.
  • Sealant used instead of flashings.

Builders seem to have lost sight of importance of fitting flashing’s around openings and rely too much on using sealants. Rather than proper methods of construction to avoid seepage causing rot around windows and possibly to concealed wall framing!

What this design fault causes:

  • Sealants will deteriorate from UV where exposed
  • Seepage will occur through joint of horizontal timber and cause rot to concealed timber. 

This can allow seepage and potential for rot to occur to wall framing and sometimes the sub-floor structure (in a two storey house). Also refer to other posts and photos for more information. Impractical design causing rot

Slab edge deterioration:

Rising damp occurring to exposed edges of the house and garage slab. Although this is a common occurrence deterioration may occur to concrete over the long term (depending on the type of soil in the area, if salts are present in the soil).
This problem must be identified in a building inspection report. This will help the buyer be aware then have it addressed by an expert, before it potentially develops into a more serious problem.
New homes with rising damp design defects
Seepage and/or rising damp to corner of the garage slab. Most likely from improper fitting of membrane below the slab before the concrete was poured.
Cracks to concrete slab of the garage area, possibly from expansion of soil causing lifting. Not unusual, but would have to be monitored for further possible movement.

Fractured web member to part of a roof Truncated Girder truss (main supporting truss to other roof trusses)Although being a small component of the roof truss, the web is still a very important part of a roof truss.
Although far less of a problem when supporting a light weight metal roof as opposed to a much heavier tiled roofThis new house fault can easily be rectified by reinforcing the fractured web section with secured cleats to both sides of the web.

No fall of floor tiles to the floor waste pipe in a main bathroom. This floor waste pipe will not serve any purpose, when leaking occurs.

New home with building and design defect

Not enough clearance between lower external walls and paving may allow potential termite access.

Some relevent material on new homes with design defects

QBCC Guide on Standards and Tolerances