Knowing the correct application of DPC and the art of installing cavity trays so they work effectively are critical parts of a bricklayer’s training, which is why they are this week’s featured modern masonry competency and the latest subject of our YouTube video series.
Never a truer word said. Avoiding the knock-on effects of rising damp by building in a damp-proof course (DPC) is fundamental when it comes to cavity wall construction. Bricklayers will incorporate this into the first three courses of brickwork above ground level for any type of new-build, as well as bed cavity trays into both skins for the purposes of moisture egress wherever there is an interruption to the cavity.
Simply put, your average bricklayer will install cavity trays and DPCs hundreds of times over in their career, and will quickly become accustomed to rolling out, measuring, cutting, bedding in and taping the joints of black rolls of DPC. They may even encounter situations where they’ll have to install cavity tray fixing strips, stepped tray details or utilise pre-formed cavity tray components.
There’s More To Installing Cavity Trays Than DPC
However, you may have noticed a trend in our approach to competence training for the modern bricklayer. Not only do we train on how the skill has been done on sites forever and a day, but we introduce trainees to new methods of construction they wouldn’t otherwise come across. Much like you read about in last week’s blog about cavity wall insulation, legislation surrounding construction calls for new innovations in building material manufacture for “high-risk” category projects.
The infamous Approved Document B dictates that only non-combustible materials with a minimum Euroclass A2-s1-d0 – and ideally A1 – fire rating are to be used in cavity construction where a building’s height exceeds 18m, so bog-standard tray damp is no longer any good to us in this scenario.
After all, traditional cavity trays are made from rolls of DPC, which are polyethylene (plastic) based and don’t even come close to achieving the fire resistance rating required. When you consider that Euroclass A2-s1-d0 means the material has “limited combustability and a very limited contribution to a fully developed fire”, as well as “absent or weak smoke emission during combustion” and “produces no flaming droplets during combustion”, it’s easy to see that standard DPC doesn’t fit the bill and offers low resistance to the passage of smoke and flames.
Manufacturer Response To Need For Non-Combustible Cavity Trays
It is for this reason that manufacturers up and down the country have worked to bring non-combustible cavity tray solutions to the market, which either carry the A2-s1-d0 rating or are fully Euroclass A1, which is defined as “a material that does not contribute to fire at any stage, including a fully developed fire“.
There are now several fit-for-purpose innovations available – each with its own set of positioning, fixing and adjustment specifications – aimed at future-proofing this area of construction and ensuring long-term compliance with any further regulation changes.
In spite of a temporary exemption to the ban of combustible products in the installation of cavity trays in high-risk buildings under amendments to Approved Document B, these non-combustible cavity tray (NCCT) systems will become the norm for specifiers and installers from now on.
ABC Assessment Centre Response To Need For Installing Cavity Trays Training
So, once this exemption is lifted and every single high-rise project commissioned features NCCT, it’s easy to see that the demand for competency training for installing cavity trays to manufacturers specifications will also go up exponentially.
After all – as we’ve been trying to hammer home over the course of this YouTube launch series – installers of these systems (now increasingly the work of the brickwork subcontractor) are being put under the spotlight, as high quality workmanship must ensure the performance of the finished systems in line with their rigorous testing and third party certification.
And this is exactly why The ABC Assessment Centre developed and wrote a short course standard for Specialist DPC Cloak Systems: to incorporate this new technology into a training course that also covers site-formed DPC cloaks – for example over lintels – stepped trays at pitched roofs and various other applications.
Check out the full course description as well as a list of the topics covered in the Course Details tab by clicking on the button below:
Next In YouTube Channel Video Series
One thing we’ve done in recent times to add to our programme of 16 short courses is to create “How To” install videos for each of the practical skills. This way, we can supplement our excellent face-to-face training with top quality video content available 24/7 from any mobile device, tablet or computer.
To give Specialist Brickwork Contractors, Further Education Colleges, Main Contractors, Designers, Specifiers, Manufacturers and Suppliers a glimpse into how the launch of our YouTube channel could be valuable to their business and individuals’ professional development, we’ve created teaser videos to accompany the long-format install guides.
The next in our series of videos is – yes, you guessed it – how to correctly install cavity trays (both traditional DPC roll and non-combustible). Filmed on The ABC Assessment Centre’s and ACS‘s patented training frames and featuring our very own Centre Manager Simon Livett and Brickwork Trainer/NVQ Assessor Ian Mitchell, we’re really happy with the finished result below…
If you like what you see, why not like the video and subscribe to the channel for all future content! Simply click the button below to go to our YouTube channel:
How Do I Get Access To The ABC Assessment Centre YouTube Channel?
The channel will have 2 types of subscription – basic and paid. Basic subscription will give you access to the promotional “How To” install videos as well as other content we’ll upload intermittently, while the paid subscription will be based on an annual fee to receive all the long-format videos and exclusive content we add over the course of the year.
