Dufferin Grove big oven burn and repair -- Dec.2023 -- Jan.2024

Dec.8, 2023

The only flammable part of the oven is the plywood of the roof, and the firefighters put a bunch of water on the part that was burning and then cut that part off. Hopefully the rest of the roof will be taken off soon. The actual oven may be able to be re-mortared and there is a good oven specialist who can be hired to come and make an assessment.

The firefighters were great, they took care when they removed the smoking parts of the roof -- the fire captain said he's eaten bread from that oven in the past :).

While the firefighters were putting out the fire. three Parks staff stayed nearby, two in a truck and one walking around. That staff person put up caution tape after the fire was out, also blocking one of the main paths to the rink. He said that no one but him must be be near the oven; that he could be there because he was paid to put his life on the line.

The oven has been in continuous use since 1995 except during the public health lockdowns (started up again a bit in Jan. 2023) -- a good run so far. It was fired during the last two days (last night for mini-pizzas for the new girls' shinny program) and there must have been cracks in the mortar of the firebricks. Wear and tear after thousands of intentional firings over 28 years.

In the evening, staff and park friends shovelled up the wet roof insulation that had been pulled out by the firefighters, and removed the caution tape that was unnecessarily blocking the main path.

What next?

Dec.9, 2023

Rink staff and park friends tarped the burned roof of the oven and removed the remainder of the unnecessary caution tape.

Dec.11, 2023

In response to an email inquiring what Parks intended to do to remove the rest of the oven roof, the new General Parks Supervisor called and asked "How can I help you?" She said there wold have to be an insurance investigation and then a discussion on what would be done, including what caused the fire and how to avoid such a fire in future. It appeared than there were no plans to include the oven builders or bakers in that discussion. She did agree to call back with more specific information once Parks had discussed it, in a few days.

Dec.14, 2023

The roof has been removed, to our surprise. Looking under our tarp, it's easy to see the cracks in the cap.

Dec.15, 2024

This afternoon we found that the oven roof had been rebuilt, again with no one talking to builders/bakers of this oven.

Dec.20, 2023, 8 A.M., from Andrea Chow, general supervisor

I do have a very positive update after connecting with the City's insurance adjuster. I'm happy to let you know that the assessment of the oven has already been completed and repair work has been initiated by the City's insurance provider.

As you noted in your e-mail, work has already begun and I've been informed that the anticipated completion date to the repairs will be December 29.

I will send an update to everyone once I have confirmation from the City's insurance provided that work has been completed and the oven is cleared to be operated.

Best regards, Andrea Chow

A/General Supervisor

Parks Operations Wards 9, 10, 11 and 13

Dec.20, 2023, 12 noon, from Jutta Mason

Thank you Andrea, The housing was put back on Dec.15 without consulting with builders or bakers. You seem not to be listening to us at all.

Please halt any further work until you have scheduled a meeting with us onsite. I know that your auto-reply said you would not be back until Jan.2 -- better to wait until then, before more mistakes are made. This oven was built and operated as a partnership with the city: a partnership means putting our heads together :)

Work was halted until there could be a meeting (in the new year, because of staff holidays).

Jan.5, 2024 Jutta to Dufferingrovefriends listserv

After the fire-damaged oven roof was rebuilt without a conversation, we asked for a site meeting between oven baker/builders and Parks management. That was set up with the help of acting general Manager Howie Dayton's policy advisor Crystal Rodrigues. It took place last Friday.

We found out that Parks had not left us out of any prior meeting -- there was no meeting, just phone calls with the insurance company. The insurer then hired the people to do the rebuild. Their prompt action surprised Parks management, not only us.

The tricky thing is that the working parts of the oven are inside, whereas the repair was to the outside of the dome and the roof. The oven is 28 years old and has had intensive use, up until March 2020 when everything was shut down. Over those 28 years some interior bricks have shifted, some mortar has crumbled. It's not easy to figure out what additional damage the roof fire and the fire hoses may have done to the insides, compared with the effect of age and usage.

At last Friday's meeting we heard that Parks and also the insurer feel that the oven will soon be ready for use again as it is. There cannot be fixes to the inside now that the roof is enclosing the dome once again. But maybe that nice old thing will make good food for another five years as it is.

When the last bits of fascia-painting and carpentry are done and Parks gives the all-clear, Anthony says that we could celebrate the access to the rink building/farmers' market by making pizza (and maybe other good dishes) in the repaired oven. That's the most direct way to find out if our old oven friend is going to be with us for a while longer.

Report from the Insurance Company:

Dufferin Grove Park Outdoor Bake Oven Insurance Repairs & Materials

This document outlines a list of repairs and materials used to return the outdoor bake oven to service after damage sustained from a fire on December 8, 2023. List of Emergency Procedures (12/14/23)  Removal & disposal of plywood roofing  Removal & disposal of insulation  Removal & disposal of cedar studs  Removal & disposal of fire brick  Barricade setup & removal List of Repair Procedures (12/15/23 – 12/29/23)  Parging of stone pizza oven  Supply & installation of fire-rated insulation (same as pre-existing) o Rockwood Safe & Sound Insulation is rated for 1177 Celsius (see description on page 2) o Photo of insulation on page 6  Supply & installation of fire brick (saved a majority of the brick and replaced about 12 comparable bricks) o Themobond 915 is rated for 1400 Celsius (see description on page 3) o Use of this product was recommended by the insurance adjuster's engineer o Photos of mortar application on pages 4-5  Reframe existing structure (built to match)  Supply & installation of plywood roof (built to match) o Photo on page 7  Supply & installation of waterproofing/shingles (built to match)  Dry ice blasting of soot and graffiti on brick o dry ice blasting is on hold  Debris removal & disposal

Jan.10, 2024

Dear Andrea, From our discussion last Friday and the insurance report you sent, it seems, first, that the oven has been well-repaired from the outside, and second, that after the last bits of work are done, Parks is ready to say oven use can be resumed.

It's not possible at this point to know how much additional damage to the inside (working parts) of the oven may have happened during the roof fire and the work to extinguish it.

Interior photos of the oven from 2015, compared to new photos from yesterday, don't show much change (see below). So it seems that the most direct way we can find out whether the oven can still be used is to go ahead and see how it works.

The question of whether the oven, at 28 years and thousands of fires, was already nearing the end of its life span, is also up in the air.

If the way we can find the answers is by using the oven and paying attention to what happens next, I'm game, and none of the baker/builders I've contacted say they feel this is a danger.

I appreciate that we were able to talk, and I hope this opens up the channel to be in touch early if new issues come up.

For your interest, as an appendix I've included the comments I got yesterday from others in the outdoor-oven network, plus two photos of the inside, below.

Jutta

Comments:

From Dale Howey (Montgomery oven): Probably the most important piece of information is missing which is the state of the firebrick shell and if they actually replaced any bricks though that would be apparent from looking at the inside. I’m no expert so I don’t know if the mortar they used will do the job of sealing any gases coming from the oven or if it will crack with time as I imagine the dome must expand and contract with each heating cycle. Perhaps there is some sort of fiber in the mortar that prevents it from cracking. Otherwise I’m sure the heat is no issue for the mortar. The rockwool should also withstand the heat though the advantage of ceramic blankets is that they can be made to fit the outer shell of the dome more closely. Multiple layers as Joel described can be laid in different directions to provide better coverage so I’m a bit fearful that the rockwool will create gaps that will let more heat escape and dangerous hot gases should the mortar crack.

All-in-all (falling mortar aside) I should think the oven could be operated for a time but I fear mortar cracks will eventually reappear. I think the best solution is a rebuild. I’ve sent a question to the mortar company as to the possibility of the mortar coat cracking with repeated heat/cool cycles. I’ll let you know what they say.

from Nigel Dean (builder of this oven in 1995, builder of three other city outdoor ovens): Photos don’t indicate whether foil “slip form” installed over dome under wire mesh……allows for differential expansion and contraction ….Repairs look good though

From Kiko Denzer (Portland Oregon; builder of outdoor ovens, and writer about them): looks like bricks are moving/moved. Does insulation fall into the oven chamber?

From Jonathan White (baker/builder in New Jersey, redid the hearth of the Dufferin Grove smaller oven in 2016): The materials and exterior work all seem appropriate. Are there interior photos of the ceiling?

From Heather Coiner (builder/baker/farmer in West Virginia): A friend of mine in Bloomington just re-mortared the vault of his oven, filling cracks that had opened in 9 years of use. Has this ever been done? Kiko noted the bricks seem to be moving, so some of them may be able to be tapped into place and remortared. In my previous clay oven we had an insulation fire (sawdust) caused by cracks in the vault. I’m not sure what caused your roof fire but it would seem prudent to stabilize those vault bricks and fill the cracks.

Also Heidrun (former Dufferin Grove oven baker and kiln builder) says that the most vulnerable area for more problems is near the front by the chimney.

Jan.19, 2024, from Joel Campbell:

Critters definitely a problem. And looks like only one layer of insulation. There should be four or five....

I consulted with Alex Chernov. See attached conversation . It's the lack of air space between the wood and the insulation. It's like I said in the meeting, the roof needed to be extended and rebuilt higher to allow more space for insulation and proper air gap.

You can see in the video how tight it is in there

https://photos.app.goo.gl/aVEKx2ak5dCv1r827

Jan.19, 2024 from Heidrun Gabel-Koepff

But it seems they regard it as finished. Supposedly, they tested with a short fire yesterday which, to be honest. is quite a different firing than 2 days in a row firing for half a day.

My main concerns are

• beside the chimney is no insulation.
• I assume the fire started around the chimney, so you would insulate that area with the insulation material. (See page 6 on the attached)
• And there is no critter protection installed. (see page 7 on attached)
• I assume over the years many animals appreciated the warms of the oven and built a home under the roof.
• I guess we simply have to deal with the 'repaired oven' and wait and see.

Feb.1, 2024, from general supervisor Andrea Chow:

I've checked in with the City's Insurance Adjustor and they have confirmed that the balance of work on the oven should be completed by February 2nd.

In the interim, I have confirmed that the oven can be used while we're waiting for the remainder of the work to be completed.

Feb.11, 2024, to general supervisor Andrea Chow:

Vijay put the first real fire in the Dufferin Grove oven today. There seems to be a bit of extra smoke leaking out of the seam at the front fascia board. It's not much, and that area didn't feel hot.

Our idea is to make a few more fires this week and see if the extra smoke persists. Also to set out some dough and see if there's any dust coming down from the inside of the mortared bricks.

Do you agree with this way of proceeding?

Feb.14, 2024, from general supervisor Andrea Chow:

Thanks for the update. I have no with proceeding with making more fires to see if the extra smoke persists.

Please let me know the outcome or if any additional issues arise.

Feb.18, 2024, from former Dufferin Grove baker Heidrun Gabel-Koepff

As far as I see the City’s insurance adjuster did the following work after removing and disposing of the damaged material.

• Parging the outside shell of the oven – the cladding with ‘Thermobond Mortar’.
  *Covering the outside shell with ‘Rockwood Safe & Sound’ for insulation.
  *Replacing 12 comparable bricks.
  *Roofing the whole oven with plywood and shingles
  *Blocking the spaces between the wall and the roof as critter protection.\\ *Painting the fascia and the common rafter in black

My questions are:

• Which and which kind of bricks have been replaced? Normal bricks or fire bricks?
  *Whether and when the inside bricks (firebricks) above the lintel will be mortared back in place or replaced.
  *What will happen if the roof catches once again fire? Will the adjuster do the same repair?
  *Is it possible and if so when to repair the hearth and dome of the oven, build the outside wall higher, insulate the space between the dome and the outside wall (like the oven at Sorauren Park), and then roof the whole structure again?

My concerns are:

• No insulation material was used around the chimney. I am certain it was there before the 28 years of usage and before the fire. I believe the fire started around the chimney.
  *No air space between the insulation material above the dome and the plywood roofing which is combustible. The insulating material might leak warmth/heat to the plywood, especially with long-time firing.

What we can try:

• Making little fires every Thursday and Friday over the next few months.\\ *Observing whether and how much smoke is coming out of areas other than the chimney.
  *Increase the intensity and especially the duration of the fires over the next few months until a former Wednesday oven usage is reached:

--8 am – 10 am firing up the oven.
-- 10 am – 2 pm pizza baking (meaning constantly high fire)
-- 2 pm – 5 pm preparing the oven for sourdough baking (heat should be around 460 F)
--6 pm – 8 pm sourdough baking

The fire in the oven goes from 8 am to 4 or 5 pm

Perhaps the result is that all is as good as it was before?!?

Attached are 3 drawings from an ‘Alan Scott Oven’ which are similar to the DGP ovens except of the red rectangles.

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Content last modified on February 19, 2024, at 02:21 AM EST