Man flue.

Our weekend disappeared as rapidly as it usually does but included the novelty of supper at a friend’s house. We walked there, a mile or so in the dark, down across the meadow and along the original Auchans track through the woods, then along the road. Andrew (our builder), Manda, Tansy and Guthrie were great company and when we left Manda and Guthrie led us on the short cut, across their land and down past Dunmore castle – so called, it was never a castle – avoiding the road altogether. Out of the blackness an explosive whirr of wings signalled a woodcock losing its nerve as we passed too close. Apparently there used to be a specific word in the O.E.D. for this particular sound, but it was ousted to make way for newer words more applicable by more people. I’d love to know what that word was. Lacking that specific word I’d describe the sound as like that of a pheasant bursting into flight.

Still on words, it seems that Acha is Gaelic for field and aucha is a variation – so Auchans just means fields.

Yesterday and today were nothing but flue. Yesterday getting everything as ready as could be for the ceremonial cutting of the hole in the crinkly tin roof, which demands dry weather. The forecast said Monday would be wet followed by a few fine, dry days. I checked the Dowsil 791 silicone I’d got for sealing the (silicone or EPDM) collar flashing onto the corrugated roof – it needs a minimum of five degrees Celsius, so I was in with a chance.

I made careful measurements before cutting the big oval out of the OSB panel, but then found the metal heat shield stopped it lying flat and had to be trimmed, a sliver here, a sliver there. The multi-tool was convenient for this but its intense vibration loosened one of the collar’s nuts until it fell three metres to the floor below…

The fireproof cement board was next; this will snuggle up tight to the flue, bridging the 50mm gap where neither OSB nor anything else flammable may go. To re-establish the airtightness, the cement board will be sealed to the flue with heat-resistant silicone and glued to the OSB with adhesive/sealant. Again I took careful measurements from the reference lines I’d drawn on the adjacent ceiling, checked a couple of times before I marked the material then, using an angled piece of OSB as a guide, I drilled a series of holes describing the oval outline – so the hole for the flue will be vertical through the ceiling’s forty-degree slope – before joining the dots with a dry-wall saw…

I knew today’s daylight hours would soon go, so trimmed the silicon collar to the right diameter for my flue. There are clear grooves on the conical part of the collar, each labelled with the flue diameter it matches.

To cut some of my anoraky story a little shorter: the day dawned fine, temperature eight degrees and rising; I removed the 500mm length of black flue then Tash and I dismantled the scaffold tower and rebuilt it outside the house; a borrowed roof ladder was wheeled then flipped into position and all the assembled bits and pieces I’d need were gathered; I climbed the ladder, marked the hole with a cardboard template and jigsawed until I could look down into the house.

The raw metal edges needed filing then painting with the sort of paint you don’t want to sniff and the heat shield top edge had to be taped to the pink roof membrane so any water dripping onto the membrane wouldn’t dribble down into the wood fibre sarking board or the glass wool insulation below.

Once that was done I climbed the ladder in the living room, slid the final metre-long piece of shiny stainless steel flue up into the rafter bracket, swung the dog-leg flue round below it until the two coincided and, with a little jiggling, slipped together. I closed the joining clip with a satisfying snap then tightened the bolts in the rafter bracket.

It just reached the crinkly tin…

So that’s almost it for today. The next length of flue was a metre and a half long, black powder coated (I’m not an admirer of shiny metal pipes in the landscape) but the silicone flashing wouldn’t slip onto it. Tash popped the silicone in the oven for ten minutes at 55 degrees and, with a wipe of water and washing-up liquid as lubrication, it slipped on a treat. Tomorrow I’ll be back on the roof trying to fix the stays to the top of this long section then, once the last shorter pieces are clipped on, we’ll take the scaffold tower down and put it up again indoors for the finishing touches – such as fixing the OSB and cement board ceiling pieces and trying to seal them.

Up the ladder indoors I stuffed glass wool back round the heat shield.

I feel I’m probably on track for the air tightness test on the twenty seventh of this month…

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Willow basket on a rope. Screwfix, Jewson, Travis Perkins and Tool Station don’t sell these, but they’re invaluable for getting little things up to the scaffold platform.