If you’re anything like me when travelling abroad, eventually curiosity will get the upper hand and you’ll be lifting up the cistern lid of a toilet to see what type of fill and flushing valve are fitted inside. 

Our fascination with overseas plumbing systems runs deep and it’s always intriguing to see how our foreign counterparts go about it. Some methods are similar to ours, some make us raise our eyebrows, others simply leave us shaking our heads in disbelief but, nevertheless, we are still fascinated. 

I’m in a fortunate position to have been able  to cast my eyes over many foreign plumbing systems, but even after over 25 years working as a plumber, for me, it never gets boring. My new role as Chief Executive of Zenten America has allowed me to take this to another level, not just to satisfy my own curiosity, but to also help me gain a deeper understanding and enable me to help create new and innovative tools for our transatlantic cousins. 

It’s interesting that while there are aspects of the UK and USA plumbing industries that have crossed the pond, it’s clear that many have not. 

I recall the first time I saw a flexible braided hose tap connector in a Florida hotel, back in the late 80’s. I remember thinking how much easier it must be to use these, no fiddly sets on copper tube to ensure the supplies were hidden behind a pedestal. You didn’t have to be creative when running a copper supply from the floor up to a bottom entry cistern and make it look perfectly vertical and join the ball valve tail with the neatest of bends. 

Of course, back then, the majority of our plumbing systems were gravity-fed and so ‘flexies’ would have created too much restriction, but it’s an interesting discussion as to whether we followed the USA’s lead or whether it was natural progression and was always going to happen regardless. The same could be said for cistern siphons. The USA has used tank flappers for years (so much simpler than elaborate siphons with diaphragms), but I see that these are now offered in the UK. 

While the design couldn’t be more simple, they function well; there’s almost nothing to go wrong, and maintenance is a breeze. The USA hasn’t really moved on from these but, thinking logically, why would they? These solutions have proven themselves for probably more than 40 years. 

However, talking of stark differences, I recently came across something very interesting called ‘hot mopping’, which is a method of constructing a shower tray (or tub, as the Americans call it). Unlike us, they have not been brought up in the culture of installing premade trays that have to be ‘jigged’ around to fit into a random space.

Instead, they take the allocated area within the bathroom and create a bespoke enclosure and tray, ending up with an arrangement that is a perfect fit. Something that really surprised me is that with these custom shower tubs you have to enlist the services of a roofing contractor to carry out the hot mopping process. Allow me to explain.

I was lucky enough to tag along with a guy called Jose whose core business is the install, maintenance, and repair of flat roofs, but he also creates hot mop shower trays. I arrived on-site just as the carpenter was putting the finishing touches to the studwork that would eventually contain the enclosure. Keep in mind that due to the West Coast being an area of increased seismic activity, it’s unusual to find any walls, be it external or internal, to be built from bricks or blocks, due to their inability to absorb any shock/movement.

The chippy did a nice job of creating a two-sided enclosure, complete with a sturdy 1” WPB base panel securely straddling the joists. The plumber had already done his first fix and a pipe stub was sticking up through the base. 

Note: California state, county, and city plumbing codes dictate that all hidden and non-accessible waste pipes and fittings must be solvent welded. Traps and waste fittings cannot utilise any form of O-ring or compression mechanical connections. Failure to adhere would result in the job not being signed off by the local city or county inspector. 

When Jose turned up, his truck looked more like the sort of vehicle you would see filling in potholes around London, complete with dried splashed tar everywhere and that familiar hot asphalt odour. 

Here’s why you need a roofer for this part of the bathroom job. Jose first laid a layer of virtually dry mortar mix on the base and carefully worked it so that it created a gentle gradient towards the waste fitting. 

The next step was to cover the two front upstands and lower section of wall studwork with standard roofing felt, simply stapled in place. He then made up a few buckets of boiling tar in his truck, heated to around 300°C and, using a mop, proceeded to apply the boiling tar over the dry mix, as well as up and over the upstands.

I certainly wasn’t there to judge but was slightly surprised at the footwear that Jose had opted to wear to do this job! Once he had applied the initial coat of tar, he then bedded cut pieces of roofing material into the tar while it was still wet. The process was then repeated until three layers of tar/roofing material had been applied, creating an unbroken, one piece membrane. 

The finished surface was relatively smooth and I could certainly appreciate how simple, yet effective it appeared to be. I doubt that water could ever penetrate this type of system, especially when you consider that a layer of porcelain tiles would then be laid on top and grouted using swimming pool-grade materials.

Jose’s final job was to satisfy the inspector. The waste had to be plugged and the tray was filled with water to a level of 4” and, in order to get a pass, there had to be no drop in level for six hours. 

The tiler was then left with a blank canvas to work on, before making way for the plumber to install the custom made glass shower enclosure, which again is apparently the norm as opposed to buying off-the-shelf panels. 

The whole process, while effective, seemed archaic compared to how things are done in the UK. However, sometimes simplicity makes sense, and now having witnessed the amount of effort being put into ensuring that the tray would be leak free, I could appreciate their methodology. 

Jose did say that, on average, these types of trays carry a 15 year warranty, but says there are many still in use that are over 50 years old where new tiles have been laid over the old. He did also comment that there are now more proprietary methods of constructing these types of trays coming onto the market. 

These use glued membranes (similar to our wetroom bases) as opposed to boiling tar, but he doesn’t think they’ll be taking over any time soon; hot mopping is a tried and tested method, so why would a customer want to gamble on anything else. 

Plus, he said that in his opinion, the culture in the USA is very slow to change, especially when it comes to the building industry so he imagines he’ll be fitting hot mop shower bases in the Los Angeles area for many years to come!