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Summer dry-out – what’s the answer?

How to beat the heat and overcome the challenges of jointing plasterboard in extreme summer temperatures

During the long, hot summer months, and especially in the northern regions of Australia, the country experiences some extreme weather conditions that can significantly affect the performance of setting compounds.

One issue when installing plasterboard at this time of year, which many installers have little experience with, is compound dry-out that results in tape lift and a number of surface and joint problems.

In hot and windy conditions, jointing compound has a tendency to dry out quicker than the nominated setting time on the bag, whether that’s a 45, 60 or 90 minute setting time.

When the compound dries too quickly, the chemical action needed to bond to the joint can’t take place, resulting in tape lift.

Consider a different compound
Although it’s tempting to use retarders under these conditions, this will exacerbate your issue rather than solving the problem. In extreme weather conditions, switching to a faster setting base coat plaster will enable the chemical action to bond the plaster to the board and maintain good quality joints. Alternatively, you can use a strong air-drying compound, such as MastaTape Universal, which cures by air drying rather than chemically setting. Follow this first coat with a high quality air drying multi-purpose compound such as MastaLite or MastaLine.

In addition to switching your base coat product, there are a number of other actions that you can take to prevent the possibility of having to reset your joints.

Make the most of the cooler hours
Firstly, taping in the cooler early part of the day can help reduce the possibility of the compound drying too quickly. Obviously, you need to get the job done on time, but planning the whole job to allow jointing at cooler times of the day will give you a much better end result.

Shorten your runs
In addition, another precaution you can take is to do shorter runs between filling the recess and applying tape so that the base coat doesn’t form a dry skin which the tape will have trouble bonding to.

Ceiling boards that are beneath a metal roof with a small cavity can particularly be a problem, and a common one, with this material being a popular choice in modern builds. Again, we recommend using the precautions suggested above under these circumstances.

Less isn’t always more
Making sure that enough plaster is applied to the joint, both beneath and on top of the tape, is also important in minimising the possibility of your base coat drying too quickly. If you’re using a mud machine, flat box or mechanical taper, it’s important to note the tool manufacturer’s recommendations for hot, dry weather. With mud machine application, be careful to bed the tape in sufficiently to provide premium contact and eliminate any air bubbles, and immediately apply a skim coat to prevent the tape edge curling.

If all else fails…
Cutting corners is never worth it, but even if you take all the precautions you can when you’re jointing in hot, dry conditions, sometimes the climate wins. If this is the case, and you need to fix the joint, it’s important to make sure that you remove all the tape and loose, powdery material along the whole joint first. Resetting only the cracked section will end up being costly in the long-run, both for potential future fixes and to your good reputation.

If you would like more advice about base coat compounds for any job, visit http://www.knaufplasterboard.com.au/compounds-and-plasters or find your nearest Plastamasta or Knauf supplier online.