Gyprock Back Blocking Cement for plasterboard installation

Gyprocksupreg Back Blocking Cement

Gyprock Back Blocking Cement is a specially formulated plaster-based cement for reinforcing Gyprock plasterboard joints where there is no framing support.

Back blocking is the process of applying a support behind an otherwise unsupported joint.

When used as required, this product will minimise the risk of joint cracking or distortion. It has a 2 hour working life.

Gyprock Back Blocking Cement is a low VOC compound manufactured by Gyprock in Australia to stringent product specifications and packed in a purple coloured bag.

Superior Adhesion

Gyprock Back Blocking Cement provides high strength and strong adhesion.

Defined Setting Time

Back Blocking Cement is a setting type compound rather than a drying type with a working life of about 120 minutes.

Easy Application

Gyprock Back Blocking Cement is easy to mix and is applied with a notched trowel.

Apply cement to the entire face of back blocks of at least 200mm width and long enough to loosely fit between framing members.

Back blocks must be cemented in position before the joins are finished.

Detailed application instructions can be found on the Gyprock Back Blocking Cement pack and in the Gyprock Residential Installation Guide – available from the Gyprock website under the Resources tab.

Product Options

Gyprock Back Blocking Cement is available as a dry powder in a 20kg bag.


More Installation Assistance

Refer to AS/NZS2589:2007 or the Gyprock Residential Installation Guide for details on where back blocking is required on butt joints and recessed joints on walls and ceilings.

Comprehensive installation instructions for Gyprock plasterboard and compounds can be found under the Resources tab and include:

For assistance with installation, try searching for a Gyprock plasterer, builder or repairer under the Locations tab.​​​​


  • Gyprock products are manufactured for life with all CSR products designed to achieve optimal performance when part of a CSR integrated system
  • All Gyprock jointing products exceed the GBCA specification for Volatile Organic Compound content according to independent testing. Test certificates are available under the Resources tab.
  • Gyprock® Back Blocking Cement is accredited to the GECA AFSv4.0-2014 Adhesives, Fillers & Sealants Standard which is compliant with the requirements of the GBCA’s Assessment Framework for product certification schemes.