Unconnected cold air return in 2nd floor master

[RSNovi]

Our master bedroom has always been hot in the summer and seems extra dusty. The room has 2 cold air returns side by side using the stud cavities. I found out that these cold air returns are not connected to the trunk in the basement.

I can see why because the floor joists change direction due to my alcove fireplace so they couldn't use the joist as a cavity like the rest. They just stuffed insulation in the block the holes in the basement. I have a couple of questions.

I am trying an experiment. The basement has a drop ceiling so I pulled out the insulation plugging the holes hoping some air will circulate up to the bedroom. Did I just create a fire hazard? Any other concerns I should have.

On the other hand, the cold air return holes are close to the wood stove so maybe some heat would go up there in the winter. They are separated from the stove by a drop ceiling.

 

[smokinj]

That should have never passed in the first place. Dont know how you would fix it without some wall damage.

 

[dave11]

To keep a fire from running up between floors, there should either be solid wood, or metal ductwork, separating the floors from each other. An open area in a wall where you can reach from one level to the next is a fire risk, though many older homes had balloon framing. Your situation would also allow smoke to get from the basement right into the upper bedroom.

Is what you're describing the way the house was originally built? Or has it been modified?

I would think the return ducts originally went to the basement and entered a duct made between the floor joists?

 

[RSNovi]

The house is just 6 years old. The duct work was just never installed and connected to the cold air trunk. The floor joists running the wrong direction made it complicated, but it seems they could have done something. At least connected one of the returns.

 

[dave11]

Hm. Hard to understand how that passed inspection.

IMO, if you're not going to run a duct there, I'd seal up those spaces at the level of the subfloor or sole plate above, with 3/4 inch plywood. Drill holes and use screws, in case you ever need to take them off.

 

[smokinj]

The house is just 6 years old. The duct work was just never installed and connected to the cold air trunk. The floor joists running the wrong direction made it complicated, but it seems they could have done something. At least connected one of the returns.

Oh yes something should have been done. Rock wool at the very least.

 

[mrfjsf]

You could always butt a register boot up to the hole and run a piece of flew over to the main return trunk if you wanted to utilize that cavity for return air, or is that not feasible?