Historic bread oven consultation needed

[chickade]

This is the bread oven at the Colonial Pennsylvania Plantation in Ridley Creek State Park, Delaware County PA (near Philadelphia). It is located at the side of a large cooking fireplace. Many years ago someone decided that the absence of a vent inside the oven constituted a fire hazard. They must have bored a hole in it and then cemented in a ceramic pipe. This pipe connects to a duct system in another room and vents outside the farmhouse.

Now the oven will not get hot enough to bake bread or anything else so it is used to keep things warm. It seems a shame. Is there anyone that could provide consultation how how to fix it? We have some masonry experience and one of us built an Alan Scott type bread oven.

Thanks, Sarah and Barb

[stonecutter]

Re: Historic bread oven consultation needed

That is just painful to see...uh.

One reason your oven isn't getting hot enough is because that flue is sucking the heat directly out of the chamber. Remove it, plug the hole and you'll see some improvement right away. An unknown is insulation. Is there any under that cladding? If not, you want to add some. I it was me, I'd remove the stucco, wrap with ceramic or mineral wool, then re-stucco. You could frame an enclosure then loose fill insulate, but then you'd be covering that great base.

Historic beehives are almost always mass based, with no insulation....it wasn't needed back then because the fire went year round and the oven never cooled below ambient tempurature. With occasional use, a mass based oven is a pain in the behind. Fix that butcher job on the flue, get some insulation on the oven, and you should be good to go.

[Tscarborough]

Re: Historic bread oven consultation needed

Easy fix, as he said, plug the flue, and insulate it as well as you can.

[Les]

Re: Historic bread oven consultation needed

Originally, how was the smoke vented to get outside the room? Is there an opening in the ceiling that we do not see?

[chickade]

Re: Historic bread oven consultation needed

Originally the oven vented into the fireplace and then up the fireplace flue. In the pictures, the duct in the adjoining room doesn't show the vent to the outside. Thanks for your help.

[chickade]

Re: Historic bread oven consultation needed

Just as I suspected. What material would you suggest to plug up the vent?
Thanks, Sarah and Barb

[Tscarborough]

Re: Historic bread oven consultation needed

Heatstop mixed up with some grog to make refractory concrete should be easy and work well.

[stonecutter]

Re: Historic bread oven consultation needed

Originally the oven vented into the fireplace and then up the fireplace flue. In the pictures, the duct in the adjoining room doesn't show the vent to the outside. Thanks for your help.

Is this oven pre-1760? I'm guessing yes.

[chickade]

Re: Historic bread oven consultation needed

The original oven was probably built in or around 1760, but it was mostly non existant when the farm house was rebuilt from ruins.

I just talked to the person who rebuilt it, and he said he used a pile of sand and covered it with bricks. We still don't know who cut the vent in the middle of it, and because historical site red tape, we can't permanently close it right now.

What would you use to stuff up the hole temporarily? We were thinking of using ceramic wool with something around it (steel flashing?, heavy tin foil) to keep it from shedding into the oven.

Your thoughts?

We want to use that oven!- it is such a shame that it is now just a warming alcove.

Thanks, Sarah

[jeeppiper]

Re: Historic bread oven consultation needed

I think I would stuff some firebrick or red clay brick in the flue, and cement in with the refractory....rather than having a big plug of refractory cement. You will want to make a temporary support inside the oven to hold the brick in place while the mortar cures.

[jeeppiper]

Re: Historic bread oven consultation needed

Ridley Creek State Park actually not too far from me...I could come help some weekend if you need it.

[chickade]

Re: Historic bread oven consultation needed

Excellent suggestion. Thanks.

[stonecutter]

Re: Historic bread oven consultation needed

Any pictures of the inside of the dome?

[Lburou]

Re: Historic bread oven consultation needed

FWIW, I would make the same repair whether you call it temporary or not. Make the best temporary repair you can manage. Consider one of those large exercise balls to gently inflate inside the oven to serve as support for the repair, like this: