cutting grates into floor?

Welcome to the forum!

Most likely, it would be a severe violation of building and fire codes.

In most jurisdictions you can cut a grate in the floor as long as you have a fire damper ducted to it. A fire damper is a spring loaded set of flaps held open by fusible link that melts at a specific temperature. A HVAC supply house can order them. Then all you have to do is install a short piece of ductwork from the damper to the grille, so that the flaps have enough space to operate. I do not know of anyone that makes a combo unit but expect they are out there.

I have recovered from an old abandoned house and have seen at antique stores, cast iron grates with flapping dampers on them, the three I have are all different sizes depending if they were in a hallway or a bedroom from around 18 inches round to 12 inches, really heavy cool items that I have considered installing on the first floor of my house and in the event I ever move to a rancher I would definatly get more of them to use. Search the internet they are out there.

Check your local building code first, but, most will alllow a simple open grate if the cieling below is NOT finished. If it is finished you would need to have a fully metal ducted opening with a fusibe damper in most locales. Yes, it is definitely worth it, you should think of them in "pairs" one to allow the heat to rise - closer to the stove in the basement (check your code for distances) and one farther away to allow the cold air to cycle back downstairs. Check your local building codes.

This passive heating is not very efficient or effective. If you want to move heat, you need to install fans along with those grates/ducts.

Before cutting a hole in the floor, you might try a simple desk fan (10-12") at the bottom of your stairs just to see how much that helps. I did that in reverse blowing from up to down and it made such a difference I put in the fan as posted here.

https://www.hearth.com/econtent/index.php/forums/viewthread/49600/

You should have better luck moving air up than I did down and you might be able to get away with something simple. Good Luck!

I have just completed an attempt of moving air from the basement upstairs.

Stove in semi-finished basement under entire upstairs. Open floor joists for the time being. That will change someday.

I have a long ranch house…about 65’ x 26’. The stairs are on the far west side of house. Kitchen, DR, and LR just east of stair. Hallway down center of eastern 2/3 of house. Beds and baths off the hall.

Prior to what I’ll explain below the basement would be 82* and the Kitchen, LR, DR would be about 68*. The bedrooms and bathrooms off the main hall would be 63* - 65*. Two-way airflow going up and down the basement stairwell. There is no door to the basement and stairwell ~4 ft. wide.

I cut one 4x12 floor vent in the far east end of the hallway and put a regular register diffuser on it. I cut another 4x12 vent on the far east end of the house (on other side of wall from stairwell) in the LR and finished with register diffuser.

I was expecting cold air to go down the vents and more air to come up the stairs. This turned out not to be the case. Temp change was barely noticeable. Had to do some tweaking.

Next step was to install a boot and duct fan on each of the vent holes. I put a boot on with a 6†inch outlet and increase that to 8â€â€¦installed 8†booster fan. The vent in the hall pulls air up from basement. To prevent a negative pressure situation in the basement I made the vent in the LR push air back down into basement. I figure, if anything, I’m slightly pressurizing the basement since they are the same fans (same CFM) and it is easier to move cold dense air.

End result is the bedrooms are now about 68* (the way we like it) and the LR, DR, and kitchen are about 70* (again the way we like it). The basement is about 78*…a little warm but the kids are down there playing so I’d rather have it warm than cold. On top of all that I’m not running the stove as hard (fans on low rather than high) and burning less wood. This has pushed my burn times on a full load to about 14-15 hours.

The duct fans are a little noisy, but less than a forced air system would create. Since I want to heat the basement and don’t want to run two stoves I think this is about the best I’m going to be able to do. I may install a rheostat switch on the fans to better regulate them in the future.

My favorite place to sit was over the grate coming up from the floor at grandpa's. At my house I too have the stove in the basement and even though there was a hole in one of the bedrooms the head didn't move very well. The hot and cold air seemed to fight itself going up the stairs and through the kitchen. I put a fan blowing down through the hole in the bedroom. And now I can feel the hot air flowing up out of the basement through the kitchen and into the living room.

Billy

I also have the same insert and asked the fire official the same question when he did the inspection following my install. He stated it was a violation of the fire code and offered no alternatives.