Fitting the Flue (Fitting the Fire Part 1)

Despite having a few weeks rest from blogging (and a lovely long weekend island hopping and camping around Scotland) we’ve continued to work ourselves silly in the house. As naturally happens when we hit September, we start to realise summer is almost over, and there is a much greater sense of urgency to sort a heating solution out.

We turned our central heating off last winter ready for all of the work we’d need to do, and relied on lots of electric radiators scattered strategically around the house. This winter however, the center of the house is more open so it’s harder to shut rooms off and heat only the spaces we’re using. Plus – it’s just painful, so we are really trying to prioritize being in a position where we can have the heating turned on again.

As part of all of the structural work we’ve been doing, we tore down our old chimney breast, put some new beams in place to support the chimney, moved some more structural beams around, and the final job on the list was to build the new chimney breast and fire. I’m so excited to say that for the first time since we moved to this house (three and a half years ago) we finally have a working fire. Fingers crossed this will hopefully buy us a few weeks to get the plumbing sorted, as it’s already starting to get cold!

If you’re not up to speed with it all, I go into our plans for it all here, including how this fire is double fronted, so we’ll be able to use it from both the snug, and the living room side.

Now I’m splitting this job out over two blog posts. We had tradesmen come in over the space of two weeks, first to build the chimney breast up to half the height it needs to be, then to fit the flue, and then to finish the chimney breast off. In between this, Lee was busy installing the hearth, drilling through it and fitting the air vent and then fitting the fire itself). For the sake of explaining the work properly I’m talking about fitting the flue and the fire in this post, and then I’ll talk about the chimney breast construction on Thursday (so this post contains a few spoilers for that!)

You might have seen in some of my previous posts that we’re fitted a vent that runs under the snug floor that means the fire draws in cold air directly from outside so that we don’t get drafts in the room.

Lee wanted to install a plastic air vent as it was much cheaper than using a stainless steel alternative (and we had some plastic ducting left over). The fire is connected to the air vent using a 250mm long stainless steel duct, but we didn’t want to connect this straight to plastic as you’d get heat transfer (and potentially melt the plastic) so instead he cast a sump into the concrete.

(The vent and sump before we cast the concrete)

The benefit of this was that we had the install the duct well before knowing the exact final location of the fire. By putting a sump in (roughly) the right area, we could fit the hearth and drill through to fit the vent once we knew exactly where it needed to be.

The hearth is 75mm thick Yorkshire Stone, picked to match the hearth that we already have in place in the living room.

Lee fitted this on a bed of mortar and once this had gone off he used a core drill to create the hole for the duct.

We then moved the fire into place, and connected up the duct to the fire.

At this point, a professional HETAS registered fitter installed the flue for us. We used a twin wall stainless steel system. We had to use this because the flue passes directly through Ewan’s new bedroom (without sitting in a chimney breast) so to comply with building regs, take up the smallest possible amount of space and (of course!) be as safe as possible this was the only solution.

We approached a few different installers, who wanted to convert the flue to a cheaper type of flue in the attic to route it to the original chimney, but Lee wanted to stick with twin wall as he felt it was a much better product.

Lee measured and drew the flue (in CAD) to make sure we could get twin wall through the spaces available, before we passed it to a flue designer who worked with us to make sure we found the correct system for us.

Our installer then started fitting the flue, staring with the log burner and working his way up. Lee didn’t want a shiny stainless steel steel chimney, so our fitter removed the original chimney pot, terminated the twin wall at the top of the masonry chimney, before refitting the original pot. The concern had was that this might have been a water trap so to resolve this we installed some 15mm copper pipe through the chimney pot mortar bed to act as weep holes to drain any standing water.

Because the pot is square, a bird guard cowl was fitted on top and the remaining (now redundant) chimney pot was fitted with a blanking chimney plate to prevent rain ingress (water coming down our chimney!)

Massive shout out to our wonderful installer Simon from who not only did a brilliant job fitting everything, he also spent an hour shortening our chimney pot by an inch so wasn’t taller than the other one. (The twin wall termination plate he fitted made it taller!).

Here’s how it looked downstairs in the snug:

The bend will be covered by the chimney breast bricks.

It then straightens out in Ewan’s room:


Where it will be boxed in with cement board, before making it’s way through the attic to connect up with the chimney.

That’s the fire in and fitted so keep your eyes out for part two in Thursday’s post where I share the work that went into building the chimney breast itself.