Tuesday, 21 July 2015

A round peg into a round hole

You'd look this smug if you had eight chimneys too.
"I delivered a load of this stuff to George Clooney's new house the other week," said the Cockney sparra van man as he dropped off flue liners and associated gubbins at The Lodge today.

"It makes this place look like a dog kennel. No offence."

Shortly after beating him to death with my steel toe-capped designer hand-made Italian loafers and dragging his bloody corpse into the woods for the badgers to feast upon, I stood in the kitchen with a glass of juice and some chocolate bourbons contemplating something much more serious: how to adapt our new bird guards to our reclaimed chimney pots.

Let's rewind a little.

Last Thursday, while Dawn was suffering from a hangover "of epic proportions" following a work night out (I was considering calling a priest) working diligently from home, I nipped to a specialist chimney place to discuss what we needed to finish off the flues before the scaffolding disappears.
We have already chosen the unbelievably expensive log burners we want for the Living Room and the Dining Room, but different people had advised us different things about the bedrooms.
Because we don't want to waste our newly-uncovered arched fireplaces by boxing them off and lobbing in a vase full of crappy twigs and fairy lights, our original plan had been to install small, relatively inexpensive log burners so guests could warm their cockles as they dozed off during the winter months. At other times of the year, when they're not being used, they could just sit there looking all pretty.
We had already dismissed the suggestion that we'd roast our guests alive ("they don't have to put more logs on..."), but someone else guessed that - being in the bedrooms - they might not get signed-off by safety inspectors in case our friends wake up dead through carbon monoxide poisoning.

As a compromise we then changed tack and decided to fit open fires which would serve much the same purpose and apparently, for some unfathomable reason, they're safer (so we were told). Nevertheless it was a reluctant compromise because in order to stay true to The Lodge and its history we would ideally need to choose cast iron Victorian fireplaces, and we're not all that keen on such things.
But this raised a new issue: to line or not to line. Some people said we wouldn't need to line the flues at all whereas others said we still could if we wanted... but liners aren't cheap, and if they aren't strictly necessary...

I hate making managerial decisions because I'm almost always wrong, so after chatting with Mr Chimney for a good hour I headed back home and held a mirror under Dawn's nose only to find, surprisingly, she was still with us.

300mm vs 270mm
Why does life have to be so difficult?
I posted ham sandwiches and medicinal grapes into her face until she was slightly less translucent then I dragged her to the flue shop and propped her up in the corner while Mr Chimney explained the pros and cons of flue liners to the top of her head.

Eventually we decided that, regardless of what we were going to fit, we would line the flues anyway and make a final decision when the time came to sort the bedrooms out.

Then, as though to underline the fact that my life is never, ever simple, came the rain hats/bird guards/pot hangers - whatever you want to call them. The cages that fit on top of the pots to stop the weather, wildlife and Father Christmas getting in.
The standard diameter of the cowl - let's call them cowls for simplicity - that would theoretically fit our pots is 300mm. No more, no less.

And our reclaimed Queen Crown pots have an internal diameter of 270mm.

Not only that, but most cowls that you see atop chimney pots are literally just that - perched on top of the pots, favouring function over form.
But we don't want to spoil the look of our pretty matching pots by clagging ugly metal cages above them and by the same token we don't want to leave them open to the elements, pterodactyls and fat flying bearded drunkards, no matter how jolly.
And yet nobody seems to make unobtrusive cowls for our style of chimney pot, despite the design being as common as muck. So it follows that all of the King, Queen and Bishop chimney pots we see around must be completely open down the flue. Why would people do that? Mad, I tells thee.

So after much head-scratching and discounting of possible alternatives, Mr Chimney (who, unfathomably, hadn't come across this problem before) suggested that we break new ground by taking an angle grinder to regular 300mm circular cowls and somehow forcing them to fit inside our 270mm pots. If we did it right the smoke draw from down below shouldn't be affected because there'd still be plenty of space between the cage and the inside of the pot, despite almost the entire thing being hidden within the crown.

As that was the only real option we had we ordered the following:
  • 2 x 7m standard 6" 316-grade stainless steel flexible flue liners for the little-used upstairs fireplaces. These have a 15-year warranty.
  • 2 x 9m tougher 6" 904-grade liners for downstairs because, according to Dawn, I am a "professional arsonist". I'm not. I am merely an enthusiastic amateur. These carry a 25-year warranty.
  • 4 x 300mm circular cowls.
  • 2 x enameled flue pipes which arrived damaged and need to be changed
  • 4 x register plates (two of which we'll replace with gather hoods if we go the open fire route).
  • 4 x 5" to 6" adapters as recommended by both Mr Chimney and Purevision, who manufacture the log burners we want.
  • 1 x nose cone, which should help get the liners down the flues without mishap.
  • 6 x 100l bags of vermiculite, intended to be poured down the flues outside of the liners in order to help deal with condensation while retaining more heat (we haven't decided if we want to use this yet as much of what we have read suggests it's more trouble than it's worth and it's not strictly necessary).
Fifteen hundred quid that we'll literally never see again
Fast forward to today and after finishing my juice and bikkies, as the remains of George's mate nestled among the foxgloves, I broke out the angle grinder and, in a stroke of genius, decided to use the stinky old dishwasher by the garage as a workbench. What. A. Pro.

With the help of the inside of the kitchen bin, which measured-in at 275mm diameter, I scribed a circle around the top of the first cowl and nervously started cutting. Once the narrow hoop clattered to the ground I did the same again with the disc below the cage, being sure to leave the securing lugs in place so they could be bent to match the new diameter.

Once that was all finished I squeezed the cowl into the pot only to find that the top disc - the rain guard itself - practically blanked-off the entire pot opening which would have caused problems with the smoke draw as there wouldn't be enough airflow. So out came the angle grinder again and I lopped the whole rim of the rain guard off so it matched the diameter of the cage below it.
And this time it was a perfect fit with plenty of room around the sides. The top of the cowl isn't quite below the lower points of the crown, but looking from down at ground level it'll be invisible, which is exactly what we want. I'll pop out tomorrow for some heat-proof paint to protect the now-bare metal edges, then Robert will be my father's brother.

All that remains to be seen now is how it draws when the liners are dropped and the fires lit (when we get them), and because we now seem to be in completely uncharted waters it's fair to say that absolutely anything could happen. We're pioneers, we are.

I was all set to start grinding the second cowl when I realised that I had been wielding power tools around in the rain for much longer than was healthy, and that's when I thought:

What would George do at a time like this?

So I made a tiny cup of overpriced coffee and lounged around seductively in the shed looking suave and ever-so-slightly quizzical as I waited for Dawn to return from work.
It was no good. She wanted to know why I was wearing shoes with no socks and, besides, she was dying for the loo.

Damn you, Clooney.


  1. Hi, does your adapted cowl actually STOP downdraughts as we have a reclaimed crown top chimney, and the downdraught stinks our room out. We were told to get a spinning top cowl as they will stop all downdraught, but they would be on show, we didnt get a nice chimney to dump that on! If your idea works then I,ll buy one this week!. Thanks.

  2. Hi there. It sounds like you're in a similar position to us in terms of what you want vs the aesthetics of it all!
    The answer, I suppose is 'no', although it was never intended to stop downdraughts - just rain and rabbits. I'm absolutely no expert, but I'd be surprised if anything existed that stopped them altogether anyway, because of the passive two-way nature of the flue pipe. I don't know enough about the spinners but I'd still be surprised although I can still see how that *could* work (or at least help) given ideal conditions.
    My layman's thoughts suggest that if the fire below was hot enough then the draw as the heated air shot upwards would be enough to prevent downdraughts anyway, so with that in mind the cooler the fire is the weaker the updraught would be, thereby increasing the chances of blowback if the wind came from the right direction. I don't know - I'm just pouring my brain out.
    Our experience is that when the fire is freshly-lit or generally too 'cool', smoke will come in to the room when I open the stove door (the house whiffs a bit when the fire's on, but it's homely and we're assuming that it's a normal part of the whole wood-burning fire experience), but when the fire is going well - promoting a strong draw - then no smoke comes in at all when the door is opened.
    I suppose the very fact that the modified cowl is there does help, but it's not perfect. If you're at the point of trying something new then it certainly can't hurt... but get a carbon monoxide detector ;)

    I imagine that doesn't exactly help, but it's the best I can offer. Good luck and let us know what you decide to do!



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