On the back of a recent Building Insights podcast, Jamie Sandilands of Grant Westfield answers Housebuilder & Developer’s questions – including on how NHBC’s new bathroom waterproofing rules mean that a ‘belt and braces’ approach is needed.
What are the recent regulation changes Brought in by NHBC on waterproofing bathrooms, AND ‘TANKING’ – and why DO THEY MEAN the former ‘belt and braces’ solution IS now the standard that needs TO BE SPECIFIED?
At the beginning of the year, the NHBC introduced new regulations around waterproofing in bathrooms. They stipulate that where there is any shower installed with a flow rate exceeding 12 litres of water per minute, there must be an impermeable waterproof layer behind the shower wall to prevent water ingress.
Previously, this would have been the system used in wetroom areas but now this ‘belt and braces’ approach has become the industry standard within all bathrooms that have a high-flow shower.
Why are the requirements challenging for housebuilders using traditional tiling practices?
Anything that updates the specification of the house and prevents the chance of damage occurring is good news for house buyers. However, for housebuilders and contractors that are using traditional tiling practices, the new regulations do make installation a bit more challenging – and can make the process more laborious and expensive. It also makes it trickier logistically as it means there’s a requirement for more skilled tradespeople to come into each house.
What were the traditional options – and why are they now inadequate for tanking requirements?
Traditionally, tiles could be fitted directly onto plasterboard or standard backer boards. Traditional options included a wet solution, or dry board plus paste. However, a full tanking system – or marine-grade backer boards – are now required to provide better waterproofing in high-flow shower areas.
If a developer wants to continue with traditional tiling methods, there are two options available, which have different costs associated with them. The most common would be the more expensive of the two, and that is pretreated marine grade boarding, which has to be installed before the tiles can be fitted to the front of it. The second way is a lot messier and more time consuming, as it involves the installation of traditional dry board, which is then treated with a resin paste.
Both mean that housebuilders have to do the first fix and then get an NHBC inspector to come in and have a look to make sure the watertight boarding has been fitted before they can get a tiler in to finish the job. This adds cost and time to the job, and is another logistical hurdle for housebuilders to have to get through.
What is the efficient ‘third way’ – i.e. A single MDF panel wall covering that’s ‘inherently water tight’ to COMPLY WITH THE NEW NHBC rULES?
The third, more efficient solution is to find a wall covering that is, to use the NHBC’s terminology, ‘inherently watertight.’ If housebuilders are able to specify a certified wall covering that meets this criterion, then there is no reason to use the other options.
How DID PROMPTING AND FEEDBACK from THE housebuildING SECTOR LEAD YOU TO PROVIDE AN answer TO THE challenge?
A number of housebuilders contacted us in 2024 regarding the upcoming changes and said they believed our panels would avoid the extra time and costs associated with upgrading the dry lining. So, we started to investigate and found the product could be independently tested to become certified NHBC compliant. It’s an in-depth process, and the testing is very robust. We put the product in for testing at the start of the year and it passed on the first attempt.
How does this option save time on projects?
Wall panels within the Multipanel and Naturepanel ranges are made from exterior grade MDF that has a laminate backing with final laminate decor on the top of it. The product is pre-treated, which saves a massive amount of time and, as it’s an MDF product, it’s much easier to cut.
WHAT DESIGN OPTIONS AND EFFECTS ARE OFFERED WITH panel optionS?
Within our Multipanel portfolio there are five ranges of products with stone-effect, marble-effect and wood-effect products all available and, importantly for the housebuilder market, we have a comprehensive tile collection. This collection includes the new XL Offset range as well as the Large Tile, Metro and Herringbone ranges, which offer a variety of tiled effects.
What are the cost advantages from moving from tiles to panels?
Even before the new NHBC guidelines came out, we were doing well with housebuilders who recognised the time and labour savings associated with our wall panels.
If you just look at the cost per metre square, our wall panels would come out slightly more expensive than tiles. However, we introduced a cost and time saving calculator, which is on our website, and it revolutionised the way people looked at wall panels as it clearly showed what the savings would be across each development.
Prior to the NHBC guidelines, we calculated that using our wall panels would save around £20,000-£25,000 and 85 hours on a 500-house development. When we reran the exercise after the NHBC guidelines were enforced, our panels came out as slightly cheaper than tiles when you consider the extra materials now required to install them, saving between £117,000 to £140,000 and around 1,000 hours on the same sized site.
What performance GUARANTEES are you NOW able to provide FOR THE PANEL SOLUTIONS?
We provide a 30-year guarantee on all wall panels within our Multipanel and Naturepanel ranges.
Are there common misconceptions IN THE INDUSTRY about wall panels?
We all remember how wall panels used to be perceived. However, technology has moved on significantly, and wall panels now compete head on with tiles from an aesthetic perspective, delivering on form, function and compliance.
Jamie Sandilands is specification sales director at Grant Westfield
To listen to the full podcast and more from Jamie on NHBC’s waterproofing regulations and wall panel solutions, visit insights.netmagmedia.co.uk