I have to say that no matter what tube you use, it will never, ever leak providing the pipe is in the right way up, and all the joints pushed together.

The problems arise when people do it wrong. They usually put the whole thing upside down, or cut the female end off one pipe so that everything above it is upside down, or else in wall there is a joint that is butted, rather than pushed in.

Never put a bend with an access in it so that the access is buried in the wall. That's another problem waiting to happen.

Even if the black metal flue is well fitted and joints correct it can still cause 'condensation' problems. At certain times of the year when perhaps the outside atmosphere is moist and temperature is low, when lighting a wood burner or even when it is finishing, there can be condensation forming inside the flue. Now I appreciate that the only way to avoid this is to have a proper double skinned flue so that cold metal will not form moisture. But what happens when you have a single skin flue already installed. Can you insulate it or somehow enclose the existing pipe with a larger one ?

Yeah, no problem. Well, just a bit. Running a single skin flue up the outside of a house is just begging for condensation problems on any day it's cold enough for a fire. If the flue is properly installed, then any condensate should end up in the stove, and you should never notice it.

Remember, even if the wood contains not one drop of water, it will still create it's own weight in water when you burn it, and if the flue temp drops below the dew point (100C) then water will start to condense and run down the flue. That's a lot of water.

You therefore have to eep the exterior flue pipe warm enough, and this means a warm jacket. Either box it in and fill the box with vermiculite or perlite. (Done properly, then as long as any wood has 6" of perlite between it and the flue wall, I wouldn't worry overmuch about it catching fire. Alternately you can wrap it in glass fibre held on with chicken wire wrapped round, but bear in mid the rain must be kept off the fibre or the perlite, or the flue will be badly chilled.

A wide bore tube filled with perlite should work well.

Thanks ! I will investigate all ideas. My favourite at this time is to give the flue a nice warm blanket and chicken wire and I wonder if this can be then wrapped round with either some more metal or even some 'plaster' type exterior material. I wonder ......

Actually that's quite bright. I hadn't thought of that.

Yeah, a good wrap of glass fibre, and then wire it on with chicken wire with a rendered coat. All you have to worry about is the top to stop water getting in thru the junction of cement wrap where it touches the pipe.

Off the top of my head, I'd make an aluminium cap that could be sealed with heatproof sealant, or something along those lines.

Help please!! We went out looking at wood burning stoves yesterday, but need some guidance! Lots of good info in this thread. What are the things to look out for? Bil, what are the "throat plates" that need to be removable?
Should we have a damper?

Hopefully Bil will do his stuff, but for what it's worth I wouldn't touch one of these lightweight Spanish ones with a barge pole. Cast are far sturdier imo. Just talking about this with a friend - the bar had its NEW woodburner going despite it being the warmest day for a fortnight!!!.. anyway, we agreed if it were possible to get a multifuel burner with a backboiler that would be the ideal. We have such problems getting water to a reasonable temperature in winter with these poxy gas water heaters! Bil if you come in re throat plates, what's a rectangular iron sheet about the size of the firebox suspended above it, with two semicircular 'cutouts' one either end? I think it's the thing that stops the fire/flames licking straight up the chimney? Mine's taken to falling down every so often - may be cos I'm over filling with wood cos it's been so cold??

To me, dampers indicate that the fire will run out of control at times needing the exhaust pipe to be choked. In short, that job should be achieved by cutting off the air coming in, but the seals etc probably aren't up to the job.

Personally I wouldn't touch one with a butterfly valve/damper in the outgoing pipe.

Fiona is quite right, that's the throat plate. Its job is to slow the passage of the burning gasses. Without it more heat goes up the flue so it is important to have one.

Also, remember to make sure there is provision to sweep the flue.

Thanks for the info Bill, I have been struggling to sleep at night lately and this has REALLY helped....














(disclaimer: this is a joke, something once very common on BE, now seriously lacking!)

Thanks for the disclaimer, else I might have thought you meant it.

The huge problem is that not everyone has a grasp of what a good system is. I see inadequate ones, dangerous ones, all the damn time, so I'm more than happy to post stuff if it helps others out.

I have to start putting it on all of my posts Bill, otherwise some people just take them the wrong way!

Thanks all, thats helped us decide! We have found a modern french cast iron (without damper!) with throat plate (looks removable!) do you think this will be good?

missed the link!http://www.stovesonline.co.uk/wood_b...aya-stove.html
Now chimney questions. We have a classic spanish house chimney with square openings either side and cone roof. are we better taking this off and putting a cowl on? Is there an optimum height?

Again, Bil's your man.... but I think it will depend on as you said, height not only of the chimney but of the house, any buildings/wooded areas etc around house, etc etc. Mine is the sort you describe (not a cone, though, more like a ridged tiled 'roof' top) and apart from the odd totally windless day it works fine.

Height, no, as long as the flue is more than 12.5 feet high. The throat plate needs to be removeable as sometimes that's the only way to get at the flue to clean it.With the terminal, as long as all the 'windows' in it at the top add up to twice the x sect area of the flue, it should be fine. I'm surprised that it smokes when the wind doesn't blow, but not when it blows. Usually it's the other way about.

I'd leave the terminal alone until you have tried it and if there is then no problem, keep on leaving it alone. Should it smoke, just check there aren't cobwebs (not kidding) in it blocking the fumes.