Good afternoon
… and a big ‘Thanks’ to those who advised on my recent query regarding laying a cement floor.
We are considering buying a lovely house in Morbihan - some problems noted but all fixable.
However we noticed that both upstairs and downstairs toilets are ‘macerator’ type with 40mm outlet pipes ….. which must, at some point, connect to or a branched to, the fosse septique.
Except for the location of the fosse, I cannot really understand why, when a 70’s extension was added and a lot of building work done, standard loos and 100mm piping were not fitted.
I am willing to ‘move’ the toilets in order to fit standard piping - and am getting SPANC to have a look.
Is it permissible to have part of the loo piping inside the house, to get to a suitable exit for fosse connection ?
Am I missing something important here ?
Should I start reading the French regulations on this ?
Certainly on a renovation we have recently done the pipes are inside for part of the journey.
It is a good idea to move towards standard style toilets - the type you have can be very problematic- you just need to be able to run the bigger pipes downhill - which isn’t always possible.
How old are these toilets? The early generation of macerator toilets have a v bad reputation (my gîte owner forum was filled with of tales of woe), but contemporary ones are said to be better.
The issue is the distance to the soil stack going to your fosse, and the fall between toilet and soil stack. If it is too far/too shallow then trad toilet will struggle. And even if you can move toilet closer, check you can get the fall you need without a macerator pump.
Most houses have soil pipes indoors, so that’s not an issue. But to get bigger pipes from A to B you may end up having to to box them in which can be an ugly and gurgly addition to a room. All depends on the house construction! Macerator toilets are not a cheap solution so there must have been good reason to have them.
You may find that SPANC are supremely disinterested in what goes on inside the house. That’s down to plumbing norms. SPANC only care about how waste water is dealt with to make sure it doesn’t pollute.
Having had to install a macerator toilet in a loft extension in the UK some years ago, my advice would be to walk away if you can’t find another solution. It was an absolute nightmare, caused by a nightmare of a tenant and her daughters, who despite strict instructions put wet wipes and tampax down the loo and there is always the risk of visitors doing something stupid.
Remember you have to have power to the toilet. Power cuts don’t help. Nor indeed someone turning off the switch!
The reason a lot of macerators are used is because you can notch beams for 40mm without the floor collapsing. It means you avoid the expense (disruption )of laying new drains and soil pipes
The answer to your questions is find the 100mm piping and work out how you get to the “bathrooms” - chances are the 100mm stack isn’t on the same wall and the beams run straight across any pipe run - and 150mm notches aren’t a good plan. Equally 150mm boxes pipe tends to be both ugly and unrealistic beyond one room.
Then figure if moving the bathrooms to the plumbing is easier than getting plumbing to them - or use a macerator.
A modern macerator is not expensive (c.€100) and can be fitted to a standard toilet. They can be a very simple solution when creating another bathroom in a different part of an old house. My only reservation about them is that the noise they make varies considerably, so worth trying to find out which are the quietest.
If you will be having a long-ish run to the fosse, stick to 100mm diameter piping; use 2 x 45° bends instead of one 90° bend; put in a rodding point and try to have a reasonable fall. Our system has 125mm pipework - but flow is slower. Also make sure that a ‘dip’ in the pipework cannot happen.
Second that very last point. It has just cost the Dèçenelle insurers of my house €3000 to have all my drainage pipes for sewage and grey water that are fixed under the house in the vide sanitaire removed and redone from scratch again, four years after the house was finished. The original “artisans” did not attached the longer runs of plastic piping to the Dalle so that over the past few years, water and waste solids from the two toilets lay in the pipework causing it to bow right down to the earth eventually snapping the pipe under one WC so that I had no idea until I got a smell for weeks and the water started bubbling in the bowl. The new work has been strengthened and attached every metre or so to the concrete Dalle now. If water cannot run freely, it will build up and something has to give