Tongue and groove timber flooring Part 1: Supply, storage & ventilation (Nat)

There are a number of fundamental requirements and procedures that need to be followed to ensure long term performance of Tongue & Groove (T&G) flooring. The following requirements are applicable where a feature floor or covered floor are placed on the traditional timber bearer and joist systems.

What are some of the characteristics of timber flooring

• Timber is a natural product that responds to changes in weather conditions. In high humidity areas the timber will absorb moisture from the air causing it to swell and increase in size. Conversely during dryer times and in low humidity areas, timber will shrink and reduce in size. This shrinkage can vary depending on the timber species and cutting pattern of individual boards.
• Where floors are exposed to the sun through unprotected windows or around fireplaces, a variation in board movement can be caused.
• It is normal for gapping to occur across a floor. However, it is expected to be relatively even, but the gap size between individual boards will vary.
• A small amount of noise can be expected from timber floors when walked on. The level of noise will vary with weather conditions.

Ordering the right timber for the job
When ordering flooring, the following should be provided to your timber supplier:

• Species
• Grade
• Profile and end joint type
• Cover width
• Thickness
• Quantity in linear metres*

You should also request from your supplier the moisture content of the timber supplied.

* To calculate linear meter quantity, the following method can be used

TOTAL FLOORING (m) = (Area of Floor (m²) X 1000) + Wastage
                                                         Cover Width (mm)

Wastage allowances should be 5% for end matched flooring and 10% for plane and butt joined flooring.

Timber flooring products should be fully protected by your timber merchants or your timber supplier to ensure appropriate moisture content. Once delivered to site it is the contractor’s / installer’s responsibility to have the timber remain at that appropriate moisture content. The timber should be protected from weather and dampness while on site until the project is completed.

Construction options for timber floors
There are two traditional construction methods when installing feature timber flooring.

• The preferred and strongly recommended method is a fitted or cut-in floor method, where the flooring is installed after the roof cladding and external wall cladding are in place and the house is weather tight.
• The second method of installation, but not recommended for feature floors, is the platform method. This is where the floor is laid prior to the erection of wall and roof framing. When using this method the contractor will find it difficult to protect against the effects of sunlight and wet weather conditions and normal day to day work practices.

When constructing feature timber floors on bearers and joists it is critical to ensure the subfloor area has adequate cross flow ventilation whether by natural or by mechanical means. Minimum requirements for ventilation are outlined in the Building Code of Australia, however, the minimum subfloor ventilation recommended for feature T&G floors is 7500mm2/m of external walls and this is greater than the BCA requirements.

Based upon Timber Queensland Limited Technical Data Sheet’s, for a full list of Timber Queensland Limited Data Sheets visit www.timberqueensland.com.au

For further information HIA members can contact HIA’s Building Services staff on 1300 650 620 or hia_technical@hia.com.au.

If you would like to become a HIA member, contact 1300 650 620 or enquiry@hia.com.au

The above is intended to provide general information in summary form. The contents do not constitute specific advice and should not be relied upon as such. Formal specific advice should be sought by members with respect to particular matters before taking action.  ABN 99 004 631 752