Uncovered fireplace and can't see whats holding up the chimney breast!

[garethep]

We have been chasing damp in our house for a while and yesterday decided to open up the fireplace in our dining room in the hope that an increase in ventilation would help having removed the plaster board and wooden frame we found this..

(I have also removed the cement type stuff from the exposed brickwork...as found it extended to the bottom of the brick arch as well as the infil bricks used to block up the opening (Ringed in yellow).)

My worry is that the Brick Arch is A) very flat and B) not supported by anything. It would appear that previously the support bricks were removed. Although the arch (ringed in green) itself appears well bonded the brick on the right hand edge (ringed in red) seems very loose.

As can be seen from the two close up photos, it would appear that there is nothing very much supporting the outer layer of the chimney breast.

As far as I can make out, this has been like this for a good number of years and hasn't fallen down yet but i'm conscious that by removing the wood and plaster support frame then I have inadvertently removed the only support it had!

My first priority is obviously to make sure that its safe in the short term or whether it needs acropropping ASAP......I suspect its probably not in imminent danger but it's always nice to get a sanity check.

Longer term we would like to recommission the fireplace....the fire back is shot so the plan is to remove it out to the blue lines and fit a log burner in the gap. the easiest method of reinstating would seem to be to rebuild the bricks under the overhang down to the hearth....this should take any vertical load but will not help with any outwards load generated by the arch. If this wont work then would I be best to fit a concrete lintel under the arch supported by bricks down to the hearth.

Advice would be gratefully received.....I'm a mechanical engineer not a builder so while I know enough to understand that it currently isnt right I don' t have the experience to know how to fix it!

 

[vinn]

Its not in imminent danger otherwise it would have already collapsed.
You could make a temporary prop with a goalpost of 4" x 2"
What is your final intention for the opening and the flue? Determine and fix your plans now, and work to any necessary future dimensions.
Select a log burner for instance, and take the dimensions needed for its installation from its manual. Dont guess - use the Mfr's Inst's.
Mfr's opening height will determine the lintel or arch height.

Sweep and smoke test the flue and have the stack and terminal examined.
Knock out the old fire back.
Do you have a suitable hearth in place?
It looks like all the chimney breast plaster needs renewing.

 

[bernardgreen]

You could make a temporary prop with a goalpost of 4" x 2"

That would be very sensible. Often an "arch" like this is held together by the plaster.
The vibraton whem removeng the plaster may have disturbed some of the mortar.
Exposing the bricks will alter the moisture content of the bricks and this may weaken the structure over time

 

[garethep]

Thanks Vinn,

That makes sense...I'll look up stove sizes etc. We hadnt really decided what we wanted as it was going to depend on what we found. A quick look online suggests that the width at the two blue lines should be sufficient which removes the need to take out any more "structural" bricks.

Intention will be to line the flue...stack is good although the mortar around the pot was broken up and the pot was loose so I've removed the pot and capped it with a large slate to keep the rain out for the moment. Flue seems in good condition from what I can see although it will definitely need swept.

Do you reckon the current arch is likely to be sufficient if supported or am I likely looking at fitting a lintel?

Cheers

Gareth

 

[garethep]

Thanks bernardgreen...that's today's job then!

 

[vinn]

As above, you must only work to Mfr's dimensions even if they require removal of more brickwork.
How can i advise on arch or lintel height's unless I know Mfr's dim's?
If the flaunching was broken up then its probable that more work will be needed on the stack. Do you have any photo's of the stack?

Where is the damp that you've been chasing for a while?

 

[garethep]

Vinn,
Understand about the Mfr's dimensions but the prime desire right now is to secure the chimney breast, increase ventilation in the room and neaten it up. once that is done I'll select a stove that fits....if there isnt one that fits then i'll fit a pretend electric one for looks. Just trying to get an idea of whether the existing arch would be sufficient if the supporting columns were reinstated or whether a new lintel will be required.
I'll get some pics of the stack but it will have to wait till its less wet and windy....I know my limits!

The damp has been from a number of sources including rain penetrating the outer wall, running down the cavity, tracking across the window lintel and coming through above the windows. There has previously been some as a result of the external ground level being raised which I think has now been sorted and yet more which I believe is as a result of there being no ventilation of the bricked up fireplace. The whole thing is exacerbated by an uninsulated concrete flat roof and very poor ventilation which results in condensation. we are just slowly working our way through the various problems as we find them.

Thanks again for your help.

 

[theprinceofdarkness]

As said, firstly support that dodgy arch. Then as I see it the lower sides of the brickwork seem to have been cut back from the general front of the chimney breast. I would brick up two columns either side, to get the front "flat", this will also add some extra support to the arch and will provide support for new new lintel when it goes in and by that time the column will be hard. Else come lintel installation time, you will have nothing to rest it on.
Unless the source of the damp is the chimney stack/breast I would not have touched this yet, its easier to open the window slightly to dry the room out.
Frank

 

[garethep]

Frank,

Had I known what was lurking I wouldn't of touched it yet either We have had similar issues elsewhere that were traced to sodden birds nests in the chimney and we gained great results from just having the flue swept and reinstating the grate. I was hoping that this chimney would be another "easy win" but alas it was not to be.

It certainly does look like the columns have been cut back......I have no idea why as the wood / plaster frame extended significantly further out into the room...another of the mysteries of the house. I've got a friendly builder to come and have a look tonight and together we will get the arch supported which will give us time to stop and decide where we go next.

Many Thanks

Gareth