ash dump diy outside air intake

[beermann]

I have copy and pasted this post from the diy section. Need help/input.

Hi I have done some searching and found some interesting results but nothing really answers my question directly. I'm sure the answer is floating around in the forums somewhere.... anyway ill get to it.

I have an old masonry fireplace with an ash dump. The ash dump leads to the basement with no outside vent options. Can I run 6" duct work from the ash dump to a window for an external air supply.

A concern is hot ashes falling down the open ash dump so can I just make a simple ash-dump cover with bricks that cover the opening on the ash dump. I've attached photos, the metal baking pan is just a visual for everyone, I would need to get a 1/2 slab long enough to reach the front of the fireplace....alternativly could I put a 6x9 cast iron baking dish over the ash dump and fit an air vent on the front of it?

....so If I place a concrete slab on the loose bricks to prevent ashes from going down the ash dump I should now be drawing air from the ashdump which has been vented to a window can i now close the vents on my glass door to the old masonry fireplace and now I am safely using an outside controllable air source?

Is this a safe thing to do?

Fireplace is ready to use and chimney is clean. I am looking for a safe diy way to make an outside air source that does not include cutting or drilling into my chimney. Here are photo's of the inside of my fireplace with some brick work I loosely laid out in the style I'm trying to set up. I am undecided if I want to lay loos brick or modify a cast iron baking dish. Thoughts?

Just wanted reminder, the metal bakin dish is used in the photo as a vidual aid. If it's a good idea to make a structure like this I will replace the sheet with a longer and thicker 1/2 inch concrete slab. Ideally a cast iron slab if I can find one....

 

[electrathon]

Where did the ashes fall before? Into the basement? I would utilize the hole that is there, I would make a heavier duct cover though, leaning more to the thin plate side and would have it fastened down so no one can move it with a poker. Build a box to round conversion, then run it out through the sill plate. Sort of tacky to go out a window. I suspect a 4" duct is enough air, but not positive there.

 

[beermann]

Thank you for your input.

The ashes would fall under the firegrate and once the fire is out and ashes are cold I can open the ash dump flap and sweep them into the ash dump. Never use it though.

I'll look into going through the sill if it all works.

As for the insert inside the fireplace, that's a really good suggestion to bold it down. I'll keep it in mind if the plan end up working for me. I think it important that the airflow is not coming directly from the back of the fire which is why ill be redirecting it to the very front near the existing air vents draw from in the room.

Keep the ideas coming. And thanks.

 

[beermann]

Where can I buy th thin plate your thinking of? Definitly going to entertain your idea BTW.

Would you be able to rough draw a basic idea and snap a photo to upload. Just so I can visualize what your thinking vs my understanding?

 

[electrathon]

Where can I buy th thin plate your thinking of? Definitly going to entertain your idea BTW.

Would you be able to rough draw a basic idea and snap a photo to upload. Just so I can visualize what your thinking vs my understanding?

Something like this. 16 guage plate would be good to handle the heat, but not massive heavy. Available at any steel yard.

 

[beermann]

Something like this. 16 guage plate would be good to handle the heat, but not massive heavy. Available at any steel yard.
View attachment 192945

I'm leaning towards doing this exact thing but I may not bolt it down. I'd like to not modify anything by drilling or bolting. Maby building it wide enough that the angle of the grate legs provides pressure and then sealing it down along the edges with heat resistant grout? I doubt heat resistant silicone would stand up to the heat?

I have a lot of time to figure it out. I still need to replace a broken glass panel, find very thin fibreglass gasket and run duct work from the basement pit to the exit before I build an insert and with your ide a can put a nice adjustable airvent on as well which would be adjustable only when I open the doors.