My ‘new’ French house has both a fireplace ‘insert’ and oil central heating. I have a question about both but I’ll put them in separate threads to avoid confusion.
Am I right to worry about having the oil tank and the oil-fired boiler in the sous-sol? It’s been there for 40(?) years without an issue. But having witnessed an oil leak disaster in the UK (oil leak undermined the foundations of an acquaintance’s house in the UK and the repair bill ran to over 100k) I’m thinking of having them relocated to outside the house. Am I being silly?
If I leave them where they are, is it safe for me to use the sous-sol as a workshop if the boiler is running for example? The ‘room’ in the sous-sol where the boiler is is about 6m x 3m.
I’d ideally like to replace it with an air-sourced heat pump system, but I just don’t have the budget.
Any & all advice will be much appreciated.
IMO any combustion device should have a carbon monoxide alarm in the same space.
By workshop what exactly? Dust can be explosive in some cases, whether that would be part of the workshop.
Hi Corona,
By workshop I mean a place where I would occupy myself with my hobbies - woodwork mostly. The place I might go to put together an IKEA kitchen unit or make a set of shelves, that sort of thing.
Made me smile, IMO always best to assemble a flat pack close to its ultimate destination.
Lol . . 
Aren’t they all? I had assumed so but perhaps not, I guess it’s not something I’ve ever really thought about.
I’ve got both the boiler and oil tank in my garage (workshop really), along with spare gas cylinders, jerry cans of petrol, diesel. Unless you’re doing some serious welding I wouldn’t worry too much.
The boiler has a balanced flue so takes air from outside so theoretically no exposed flame indoors.
My oil tank and boiler are also both together in the cellar, though around 4 metres apart. Been like that for at least 25 yrs without any problem.
There are however some rules to be followed.
- The oil tank should be surrounded by a ‘bund’ wall or other containment that is capable of holding the entire contents of the tank in the event of a leak. I believe that the modern double walled plastic tanks fulfill this requirement. Mine is an old steel tank, so it has a concrete block containment wall around it built with the solid blocks rather than the hollow ones.
- The ceiling above both the tank and the boiler has to be of non-combustible material. Mine have an 8 inch thick reinforced concrete floor above them, so no problem there.
- There must be an adequate supply of fresh air for the boiler. We have a big grille over the cellar steps to the outside, so again, no problem.
- The door between the boiler space and the rest of the house must be capable of holding back a fire for 30 minutes. One can either purchase such a door and frame (expensive), or use fire resistant plasterboard covered with plywood to beef up an existing door. Don’t forget to also beef up the frame, and preferably fit a smoke stop strip around the edges of the door.
- Finally, as @Corona has previously mentioned, install a carbon monoxide alarm and don’t be tempted to go down into the sous-sol if it goes off. Instead, cut off the electrical power at the distribution board, and open the garage door (assuming that there is one) from the outside to ventilate the space before entering.
As long as you have good ventilation, and the carbon monoxide detector, you should be safe doing your work in the sous-sol.
We don’t even have a sous-sol, so they are both on ground floor in an internal utility space. Have been for 25 years+.
In our Oxfordshire home we have a double skinned plastic tank outside. Originally it was steel but it began weeping and we replaced it around 10 years ago. Heating is through an oil fired Rayburn in the kitchen.
I’m getting ready to ask a plumber to come and do some work on my bathroom. I think I’ll ask him how much it would cost to shift the lot outside. I could build a bund myself and, once the boiler and tank has been relocated, I could build a lean-to around them so they’d be out of sight.
My 3000 l oil tank (now redundant) is buried under a garden path, and the boiler was in its own little room off my laundry room.
Indeed, there are a lot of installations that do not comply with the regulations, and even today there are installers who will do whatever is quickest and most convenient rather than that which is correct.
How far an individual will wish to go to bring an installation into conformity, usually depends on their views regarding the importance of limiting ecological damage and fire spread in the event of a malfunction.
The really essential thing is a supply of fresh air into the space where the boiler is situated, as without adequate ventilation there won’t be efficient combustion of the fuel. It’s like driving a car with a blocked air filter in that unburnt fuel clogs up the interior of the works and the flue-way. Lack of an adequate air supply will cause more fuel to be used. The manufacturer of the boiler will be able to tell you the minimum size (in square centimeters) of the air supply required. The simplest way to provide the fresh air may well be to install grilles in the external door. The air supply must be completely separate from the exhaust gas flue to the chimney.
Moving the oil tank outside into an unheated space usually requires the use of the slightly more expensive ‘Fioul Superieur’ in order to reduce the risk of the fuel supply lines freezing in winter. The balance to the increased initial expense of buying the higher grade fuel is that there is a consumption saving of around 7%, so the overall cost of a season’s heating is about the same as with ‘Fioul Ordinaire’.
Sorry if it sounds a bit obvious, but don’t forget that the fuel delivery driver will still need to be able to get his hose to the tank for replenishment.
If you do decide to move the boiler outside you will obviously need to adapt / replace the exhaust gas flue. I believe the requirement is for stainless steel pipe, that last time I looked, costs around €30 per linear metre.
Depending on accessibility, you may wish to consider covering the underside of the woodwork above the existing boiler location with the pink coloured fire resistant plasterboard to be found at builder’s merchants and the larger Brico stores.
Like many other things, at the end of the day it will be a balance between safety, practicality, and cost. I had been thinking of changing our installation to run on the new 30% ethanol fuel mix, but because of access constraints it would be so expensive as to make it impracticable, so I have had to use other means of reducing our carbon footprint.
All sounds a lot of work, just how expensive is the ASHP?
St Peter was a very short man. 
Thanks for that - brightened up my morning 