Hey friends,

Nice to have some dry weather for a change ehy? Sorry for my absence of late but I do have some good progress to share today.

🧱 Installing a Fireplace Lintel

This is where we left off. I was naive going into this project. I thought I'd could take off the stone facade and maybe remove a few bricks and I'd be done. Instead, there's no obvious builders opening, no lintel and some pretty shoddy looking brickwork. I've got my work cut out.

First I removed the gas fire insert. I'm pretty sure it's not asbestos but I treated it as if it were and was careful removing it and masked up. I then put in a timber post offcut to support the brick above.

Behind the gas fire was a 'throat' made of cement towards the bottom but bricks higher up. This has got to be removed in order for the pipe flue to go up vertically into the chimney.

Once the cement was removed I could see the blackened bricks at the back so at some point it must have been open this far back.

To get access to those corbelled bricks at the back, I needed to remove the bricks at the front. You can tell this front portion of bricks has just been filled in as they were in a vertical line rather than in an offset pattern. Also the front bricks were only 4cm thick which didn't inspire confidence so I removed all of them until I reached a full sized brick. Now I had a clear hole.

I got rid of the gas fire at this stage too. During the removal of the brickwork I'd wiggled it too much and could smell escaping gas - whoops! I shut the gas off at the meter and called a guy to come cap the pipe below floor level. This needed doing anyway of course. £85.

Before continuing I had to learn the figures that you need to adhere to with stoves in recesses. Some are building regs (Approved Document J), some are stove manufacturer's guidelines regurgitated as fact. Reading up on it gets confusing.

The first thing is there is no definitive distance a stove needs to be from non-combustible materials, i.e. the sides or back of your fireplace. However you do want decent air flow so 50mm is probably a minimum with 150mm+ desirable. You certainly want the sides wide enough to get a vaccuum nozzle in!

However the side and back walls need to be at least 200mm thick.

200mm on the sides (blue arrows) is also the width required to hold up the chimney stack sufficiently so that limits the width of my opening but I should be able to get 800mm-ish. As a 5kW stove is range from 420 - 550mm wide that leaves a roomy 125mm+ on either side of the stove.

In regards to the back of the opening, the stove fitter suggested I'd be able to get to a depth equivalent of the red arrow. However that measurement is only to a single skin wall and I need the back wall to be the depth of the green arrow (200mm+). So I can't take the back wall any further back than the blackened bricks I've reached. That leaves me with a fireplace depth of the purple arrow which is about 360mm.

A stove is roughly 330mm deep so in order for the front of the stove to be flush with the front of the fireplace I have about 50mm at the back once the wall face is plastered. Most of the heat generated comes out the front, sides and top so it should just about be okay. If not, it may have to stick out the front a little bit.

Here's an example of stove dimensions so you can imagine things better:

You can attach your flue to either the back or top of a stove. I won't have any room to spare at the back and instead it will attach to the top (as is common). But this brings me to the next issue.

I've often wondered why you see oak mantels floating above the fireplace opening. It looks odd.

But now I know. The distance between the flue and combustible mantel needs to be 3x the diameter of the flue. Most flues are 5 or 6". Assuming a 5" flue that's 15" (380mm) distance - the entire depth of my opening. This can be reduced to 1.5x if you use a twin wall flue or a heat shield (a metal plate behind the mantel with a minimum 12mm air gap between the two to prevent heat transference). That's still 7.5"/190mm, which I won't have.

We do want a mantel, it looks nice, you can hang stockings on it and Abi likes to display cards (for many months after a birthday has occurred 🤷‍♂️). I'd like to avoid it floating so the options are to:

1) have a couple of elbows so the flue is towards the back of the chimney (I think you need about 500mm above the stove to accommodate the elbows and it probably adds some expense to the project).

2) Go for a non-combustible mantel. You can get ones that look like wood. That might be the sensible option, if we can find one long enough for our strange chimney. Of course there are stone options but they look best with a proper surround which is a bit too ornate for our house.

3) Through some research I found a skin that goes over the flue pipe that reduced the distance to only 1x the width of the pipe so that might be the best option.

Back to the project.

At the top I've drawn where the flue opens up and then narrows again. At the bottom I've sketched the rough opening I want to achieve. The brick in between marked in red will be unsupported so it needs to go. I'll then need to get a lintel in and fill in the brickwork at the front of the chimney.

Supposedly if you remove lower bricks from a wall only a triangle above it is at risk of falling down because of the pattern of brickwork. Like so:

Yeh well, I'm not risking it with this dodgy looking brickwork collapsing on me like a literal ton of bricks. Bring in the strongboys!

I've not done this before so it's pretty exciting! The strongboys are heads that sit on top of acrow props that allow you to support brickwork when you don't have anything to put an acrow under.

I've rented 3 along with Size 0 acrows (about £50 for 2 weeks). The strongboy website suggests you only need 1 support per 900mm wide brickwork but it's my head on the line so I'm going to support each brick individually.

At this point I'd cleared out the brick on the left side and it's black with soot too so must have been the original builders opening - yay!

On the right you can see the line where it's likely the opening was. The next layer of brick is only 100mm wide and then it's the next fireplace and I need 200mm between the two. Since the brick inside the opening is at a weird angle I decided to remove it all and start again with a new column up to where I want the lintel.

New brick in place. I also mended the left column as best I could. I used a premixed mortar which is a good time, and wrist, saver even if it costs a little more than buying sand and cement separately. Used 4 bags for all of the following work so about £40.

Next I cut the concrete lintel with a masonry cutting blade on my angle grinder. It only takes up to 125mm blades but was just enough to cut through from one side then the other.

The lintel is 100 x 65mm with a steel rod through the middle. I looked into sizing required for this job but couldn't find much information so went with the most common one. It's overlaps the brick by 4" which is the minimum recommended. 6" would be better but I didn't want to eat into the left columns too much. No padstones required under concrete lintels, only for steel.

I got it level and waited a day for the mortar to set before carrying on.

I then filled in the brickwork, including continuing the new right column of brick upward to meet where the flue narrows. I removed one acrow and filled the gap.

And once set I removed the last two acrows and filled those in.

The lintel is about 1m up from the future hearth stone. There's a balance between creating too high an opening where the wood burner will look too small or too low where the mantel will look odd. That is perhaps another reason why you see mantels floating higher up.

I'm pleased!

There are a couple of things I've noticed along the way:

• If you look closely at the brick on the sides of the chimney it's mostly broken brick so I believe the sides must have protruded into the room by half a brick at some point which would have supported a mantel above. I reckon there have been 3 iterations of this fireplace before this work and the last with stone facade was when the front was cut back flush.
• The lack of lintel was odd but I found this hole on one side which I'm sure would have been for a steel rod once upon a time. Again, I think it was removed and the gas fire insert was used to hold up the chimney instead. I guess all the brick was to create a narrow chimney to get a better updraft.

Next I moved onto the other fireplace. I know from looking in the vent on the other side that it's not blocked up but this side being the back of the fireplace would be two bricks deep.

First I removed a couple of layers of bricks above where I wanted the lintel which makes it easier to get the lintel in plus this was as low as the acrows would go. I used just one acrow/strongboy this time and removed all the brick below.

Then I cut out bricks either side to install two lintels next to each other.

I then removed the vent and bricked up the hole. This alcove is of course 1 brick deeper than the fireplace as the wall is single skin. There is a lintel of sorts above it.

Here they are side by side. I think it's going to look okay. We've decided, or rather Abi has told me, that the mantel needs to stretch all the way across and therefore the hearth should as well so that's my next job.

👋

Elsewhere I've been busy at the previous house helping my mum readying it for re-let. Lots of little jobs not really worth writing about, this trellis I put up was the best of the lot. The other side of the wall is my mum's kitchen so this was our solution to prevent kids from kicking a football against it.

The tenants wanted it unfurnished so this is the garden room presently. It's good to put it to use even if just for storage.

The boy nicks all our blackberries before I get to them but I've founds loads in the fields beyond our house. I'm going to go out with a bucket this weekend so I can have blackberry smoothies all winter long. I reckon I can pick a £3 punnet's worth in about 2 minutes so that's £90/hour paid in blackberries 😁.

Hit "reply" if you've got any comments on this week's newsletter – otherwise I'll see you next time. Have an epic week :)

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