The codes of practice governing fixings provide guidance about the recommended fixing type, penetration depth required for fixing ceiling and plasterboard systems. Steve Menary takes a look at some current activities in the tools and fixings sector.
Of all the issues facing specialist plastering and drywall contractors on site,
the use of tools and fixings is one that can often be taken
If contractors do consider the subject, the reason will generally be solely how to improve productivity using new tools such as rapid installation guns that drill and fix a chain of fixings faster, cordless metal cutting saw for cutting metal profiles or mechanical jointing tools.
Sara Whittington, senior category manager at Gyproc Tool Hire, Artex, says: “Mechanical jointing tools, [are] on average 52 per cent quicker, which ultimately improves the productivity of a workforce.”
The same approach applies to fixings, where productivity is again the main focus from adhesive options for plasterboard such as quick set Polyurethane foams, which normally has a two hour set time, are increasingly popular, to the Speedskim system.
Speedskim uses a semi-flexible PVC blade to flatten the skim coat in seconds. This blade reduces surface moisture, which enables specialist contractors to get a second laying down coat on immediately then the Speedskim system means the plaster can be flattened back straight away.
“Like a lot of plasterers I was sceptical at first about this new tool system” says Scott Beaumont of Kent-based Scott Beaumont Plastering
& Rendering Contractors. Since then, Mr Beaumont
has bought the 1200mm system for skim coat and backing plaster.
Yet for all this plethora of labour-saving innovations, how much thought do specialist contractors give to whether they are using the appropriate fixing or tool?
“From our point of view, the benefit of using the correct fixing is to make sure the board actually stays up,” says Chris Woollard, category group manager at product group CCF: “It’s really that simple.”
That simple, but not necessarily widespread. And if contractors do not select the correct tools or fixings, the implications can be significant.
Working on facades, for example, problems can range from using the wrong anchors to untrained installers not putting in anchors correctly or even not using the right
Fixings failures are not always evident until a full façade is constructed, so should specialist contractors do more research before actually starting work?
Wind load calculations are regularly used before putting up external cladding and rarely internally but in some circumstances they can be necessary to test the pull out strength of the fixing.
Kevin Davies, product manager at Sto, says: “There are a number of reasons why you may carry out pull out tests to check the fixing or pull over tests to check the board pull over strength. There has to be a reason why the tests are carried out internally which may be a heavy internal lining system or a new frame type for example.
“In order to check pull out, the fixing manufacturer will normally attend site and test fixings into a substrate using a direct tensile test. The fixings is normally attached with a special washer which will fit the test equipment. The equipment is then used to pull out the fixing and the force measured.”
To calculate a characteristic pull out strength of a fixing, up to 10 repeat tests may be needed.
Wind load calculations are generally carried out prior to cladding being erected, so there are no major consequences to a failed test, but a failed internal pull-out test is different and the outcome more severe.
“If the pull out tests indicate lower strengths than required it may be an option to increase the rate of fixings per metre squared or use a different fixing,” adds Mr Davies. “For internal installations it is important that the correct fixing is used from a durability point of view. As an example, in the internal area of a swimming pool, the fixings must be suitable for the environment and be the appropriate grade of stainless steel.”
Ceiling collapses are another area where tests can be beneficial.
A survey by the Association of Interior Specialists identified 10 reasons why ceilings collapse. These ranged from incorrect selection or installation of fixing, additional load being applied, insufficient number of fixings, people walking or crawling on ceilings, and a failure to follow manufacturers’ guidance.
Other reasons given in the survey include modification by other trades, insufficient supervision or training, structural vibration causing fixings to fail and substitution of specified components.
Richard Blain, the interior finishing trade manager at tools supplier Hilti, says: “In the fixings market we’re seeing issues where contractors either chose the wrong fixing or they chose the right fixing but use the wrong tool.
“This is most noticeable in ceilings and we’re made aware of defective ceiling installations once or twice a month. Sometimes the wrong product has been used and other times its installers not installing systems correctly.”
“There’s a high proportion of labour only subcontractors who use their own tools and may not fully understand the complexity of fixing selection.”
Chris Rose, from ITW Construction Products, said: “I don’t think you can underestimate the importance of choosing the right fixing. What can often seem as an opportunity to save money by using a non-approved anchor or a lower cost per unit fixing, can often result in a long term financial cost or worse.
“Increasing efficiency with high performance innovative products, along with a programme of continuous
end user education and training, is the best form of error prevention.”
Mandeep Bansal, Technical Services Manager at Knauf, said: “It is crucial to use the (plasterboard) materials that are specified otherwise the finished wall or ceiling will not perform as it should.
“Potential system failure could come as a result of fixings in three main ways. First, where there are insufficient fixings. Second, where fixings have been incorrectly applied and finally, system failure may occur if the fastenings are not manufactured in accordance with BS EN 14566 and tested as a component of a system to BS EN 1364-1.”
For a simple process, tools and fixing can be complicated and is one that specialist contractors clearly need to consider.