Widening Chimney Opening

[DIY_DIDDLER]

Hello, I am pretty far along in my house reno - many thanks to all the posters here! We would like to put in a log burner, this opening is where the gas fireplace/backboiler used to be.

As shown, its rather small. It is currently 590wide and 570 tall. I think a good size would be 900 x 900.

My lintel is rather high, and not very wide so I imagine this needs replacing, or another inserted below? (considering I don't need the opening that tall). It also has a crack in the middle, but it doesn't look very wide / deep and I imagine this is OK as well as it has no where to move? At least thats what my structural eng said about the lintels above my door

There is plenty of info and videos on how to add / change a lintel - I just find it hard to understand the makeup of a chimney and am hoping some here can advise, I have posted a photo of the chimney and the inside looking up.

I am a bit confused by the ^ shape brickwork. it starts just at the vertical opening, where there is a steel plate. I assume this is ONLY holding up all the brickwork under the lintel?

I can't see that there is anything above them. when increasing the height of the opening is it safe to remove these?
This is a semi detached. So this will back onto the same chimney as the neighbour, there are 2 pots on the roof. In the bedroom above here the brickwork is a lot skinnier.

1. Whats the best approach to widen and tallen this opening? Replace lintel with longer one and do a similar metal plate to get the desired height or insert another lintel at the desired height?

2. Can I remove the ^ safely or does it need some other structure instead?

3. I'm not against hiring somone, rough cost? (I am pretty competent DIY so it couldn't be silly money)

Many thanks!

 

[Wayners]

Old steel flue from a wood burner up inside chimney?
Just install a new concrete lintel.
Cut the hole bigger and cement in. Probably lime mortar.
Cut opening bigger and nothings will happen.
Will all hold together

 

[DIY_DIDDLER]

Old steel flue from a wood burner up inside chimney?
Just install a new concrete lintel.
Cut the hole bigger and cement in. Probably lime mortar.
Cut opening bigger and nothings will happen.
Will all hold together

Thanks for you advice.

Its the old duct for the gas boiler/fireplace that was there.

Just to be clear, do you mean remove the current lintel, cut the sides bigger, and install the new lintel? I wouldn't need to put in some strongboys or anything?

Cheers

 

[ree]

OP,
You must install the burner to Mfr's installation dimensions - so you first need to select a burner.
Why not use the search button to find member: ree - search: opening up a fireplace?
There you will find a number of my recent posts on how to do what you propose.

For now, leave alone the SS flex flue liner that was used with the old gas fire.
Dont remove any brickwork until you have the Mfr's dimensions.
Then come back & I'll help you to safely install a lintel.
The gas pipe and gas restrictor valve, & any elec cables or devices must be removed by qualified people.
The flow & return pipes from the old boiler must also be removed back to any cylinder.
Might be best to remove all the board & batten as well.

 

[DIY_DIDDLER]

OP,
You must install the burner to Mfr's installation dimensions - so you first need to select a burner.
Why not use the search button to find member: ree - search: opening up a fireplace?
There you will find a number of my recent posts on how to do what you propose.

For now, leave alone the SS flex flue liner that was used with the old gas fire.

Thanks for your reply. Yes was planning to leave the SS liner for when the HETAS people come.

Those are completely dead pipes, I should have specified. My plumber did all the work of installing a complete new heating circuit and gas pipe to the new boiler location, I appreciate you checking though!

I have a few burners that I like the look of, and all would fit well within a 900x900 opening. Far as I know you cannot have "too large" an opening so as long as I have options this should be fine.

I agree that I will likely remove all the board and batten and have it re-boarded once the fireplace below is done. I will go have a look at your post history, many thanks for your input!

I did receive a quote of £4k for the complete work. This seems steep to me, so I'm hoping if im only paying a HETAS for the flue / register plate/ connection to stove that should hopefully save me some.

 

[ree]

OP,
Remove all redundant pipework esp. gas pipes & devices.
The upper lintel in your first pic could possibly be left in place, & might well do for lintelling the new opening.
The price is what it is.
HETAS will only do the full installation procedure which will(or should) involve examining the flex flue terminal on the stack, smoke testing, & evaluating the condition of the SS liner, & more.

 

[23vc]

65mm concrete lintel at whatever height you think looks good. Then likely to need small steel lintels at right angles to it, to support the corbelled “gather” brickwork.

 

[DIY_DIDDLER]

@23, thanks for those photos, nice install!

I have removed the brickework up to the lintel, I have also removed some of the brickwork that was loose to left, where the back burner pipes used to route.

Red lines is where I would like to open to - considering standard lintel sizes of 1200 / 1500. So I would need to be removing bricks that are in contact with the gather work.

Can anyone explain where the loadpath for the "gather" brickwork on the left side. The purple line shows its path. I imagine this is taking a massive amount of weight, and I don't understand the loadpath considing those removed bricks otherneath it. the "exterior" brick course on the far left had an opening already in for pipework when we got the house.

this last photo is through an access hole on the far left exterior of the chimney breast - was already here. I have not removed any bricks that weren't 'loose'. I do not understand how this is being held up!

 

[23vc]

They’re corbelled, which helps them to be self supporting, and also toothed into the back/front of the breast
If you end up needing to remove some of it, causing it to be undermined, you can get those little corrugated lintels (visible in my top pic bearing onto the conc. lintel) to support it

 

[DIY_DIDDLER]

Right, so am I understanding:

the gather, is toothed to the back (party wall?) and front (chimney breast face). In my photo the chimney breast face is only 1 brick wide., and obviously where I took out bricks (middle photo with hole) there is no load support under. You can see I have 1 toothed brick at the bottom clearly visible (that the old iron bar sits on). So if I removed this brick, there may be a course or 2 that would collapse, but above that the flue/gather is tied into the front and back of chimney?

So those steel lintels in your photo may only be supporting the bricks "hanging" from a toothed brick?

Apologies if I'm being convulated, I really appreciate everyones feedback!

 

[23vc]

If you ignore the bottom area for now, look at where you want to cut your new lintel in, at that point, the gather brickwork will be somewhere in the middle of the opening, and no longer supported by corbelled brickwork below it, so that’s where you need the steels. Once all that’s in place, your face brickwork and the gather brickwork is supported and you can just take all the lower stuff out.

As it is, until that’s done, it looks a bit dodgy with that big hole in the side so I’d not take any more brickwork out down there, but concentrate on getting the lintels in.

 

[DIY_DIDDLER]

Makes sense. I couldn't see any similar threads how the steels are fixed. On the front they rest on the new lintel, how does it get fixed on the back? Where a toothed brick would be removed?

Is the gather wanting propped below while doing this?

Again, many thanks for your help 23vc. Even if I decide to get someone in it's very valuable to me understanding this.

 

[23vc]

Back of the steel just goes into the back wall. Can stitch drill it out, doesn’t need a whole brick removed as they’re only small. I didn’t prop anything, just be careful and ensure things are generally supported as you go. The metal lintels probably aren’t always necessary/used, as theoretically the gather is toothed, but I’d go belts and braces for the minimal cost and effort of putting it in