With changes to H1 well and truly here we are seeing some interesting inventions and ideas surfacing to address the new requirements.  Not so new is the move to increase R Values by simply increasing traditional insulation thicknesses.  With thicker insulation comes more weight and there lies the question we are getting on a regular basis to the GIB® Helpline: “…will this extra weight change affect the ceiling linings?...”

Short answer is, if the increase in R value is delivered through additional commonly used insulation materials this increase will not affect the plasterboard ceiling linings.

Considering any potential affects of increased weights requires us to look at all parts involved and the process or order in which everything is installed.

NZS 3604:2011 – section 13.1 specifies that “…ceiling material shall be less than 17.5 kg/m2…”

Let’s look at an example:

If, as a minimum case scenario, a 10mm thick GIB® Standard ceiling lining was used which would require battens at maximum 450mm centres.  This lining would be installed with the prescribed screws as written in our GIB® Site Guide:

• Metal Battens — Minimum 25mm x 6g GIB® Grabber® fine thread self-tapping screws
• Timber Battens — Minimum 32mm x 6g GIB® Grabber® high thread screws

And these screws were placed, one in the middle and one each edge on the taper. Adhesive is specified as daubs at 200mm between these screws and no closer than 200mm to any fasteners.

With the weight of the ceiling insulation being distributed over the battens and other framing members, we know some of the weight will be applied directly to the back face of the plasterboard. We have an understanding that the screws and glue daubs have a certain holding power. All of this together we can say with confidence that the ceiling construction plus the additional insulation will not exceed the typical ceiling weight limit, and that the weight of the additional insulation will cause no issue with the ceiling, like sagging of the linings.

Understanding that there may be a difference between any brand of Plasterboard available in the market and our GIB® Plasterboard range is important to consider. Whilst we manufacture our plasterboard range to meet the requirements of AS/NZS 2588:2018 (Manufacture of Gypsum plasterboard), where we exceed the requirements, this can be counted as “redundancy” beyond what we have stated above.

You can be confident then that additional typical insulation materials will not exceed the ceiling weight limit or cause issues such as ceiling sag.