Pre-1980 Australian homes are a distinct flooring category. The timber subfloor that characterises most homes of this era — Baltic pine, jarrah, cypress pine or Oregon depending on the state and period — is simultaneously the home's greatest asset and its greatest complication when it comes to new flooring. Getting it right means understanding what you have before you decide what to put over it.

What "timber subfloor" actually means

In a pre-1980 home, the structural floor is typically 19mm tongue-and-groove timber boards nailed to floor joists. In many homes this original floor is still present under carpet, vinyl or linoleum. In some it has been overlaid with particleboard, plywood or self-levelling compound in previous renovations.

This subfloor is the foundation for everything above it. Its condition determines what installation methods are available, what preparation is required, and what the final result will look and feel like.

Step 1: Check what's under the carpet before you decide anything

This cannot be overstated. Before selecting a floor or accepting a quote, pull back a corner of the existing floor covering (in a cupboard or behind a door) and look at what's underneath. You may find:

Any professional flooring company should inspect the existing subfloor before providing a final quote. Be wary of quotes provided without an inspection.

Installation method options for timber subfloors

Secret nail — engineered hardwood — the premium option and often the most appropriate for this home type. Engineered hardwood boards (minimum 12mm thick) are nailed through the tongue to the timber subfloor. The result is a solid, quiet, authentic floor that matches the character of the home. Can be sanded and refinished over decades. Requires: structurally sound subfloor boards, moisture content within acceptable range, and preparation of loose or damaged boards.

Floating — hybrid SPC or engineered hardwood — boards click together and float over the subfloor on a foam underlay. Can be installed over timber subfloors with subfloor prep to flatten the surface to within 3mm over 1.8m tolerance. More forgiving of minor subfloor irregularity than secret nail. Suitable for timber subfloors that aren't in good enough condition for direct nail-down.

Particleboard overlay then float — if the existing subfloor is too irregular for direct installation, laying a particleboard or plywood overlay first creates a flat, consistent substrate. Adds height (typically 12mm) and preparation cost but enables a quality floating installation.

Subfloor moisture in pre-1980 homes

Pre-1980 homes are frequently built on timber stumps with the subfloor space open to the outside environment. This means the underside of the floor is exposed to outdoor humidity, particularly in climates with high ground moisture. Before installing any hard floor, a moisture content reading of the existing subfloor boards should be taken. Acceptable moisture content for installation is typically below 14%.

Where moisture content is elevated, the source should be identified — inadequate subfloor ventilation, plumbing leaks, or high water table can all cause elevated moisture in timber subfloors. Address the source, not just the symptom.

Pre-1980 adhesives and asbestos

Some adhesives used with vinyl and linoleum in pre-1980 homes contained asbestos. If you are removing existing vinyl floor coverings in a pre-1980 home, do not sand or dry-scrape the adhesive. Have the adhesive assessed by a professional if you are unsure. Your flooring contractor should be aware of this and handle it appropriately.

Use our Floor Finder — it captures home age and existing floor type and takes these factors into account in its recommendation.

Get a personalised recommendation for your home
Our Floor Finder uses your suburb’s climate data, home type and household to recommend the right product with a full spec sheet.
Get my Floor Report →