Bathroom Exhaust Line Tear

[thapranksta]

Whole cutout

Two pieces of Advantech with T&G sawed off placed inside cutout

Pieces of Advantech currently screwed to existing floor between joists.

Box I built to support edge of new subfloor by the wall parallel to joists.

Is the box parallel to the floor joists a good idea? It is a size where I have to apply a little pressure to wedge it in there. A little less than half of the top of the box (1.5'' or so) will be exposed for screwing down the subfloor. If the box is a good idea, do I need to build boxes for the wall perpendicular to the wall as well or can I use strips of the flooring like I did for the part connecting to the middle of the floor? Hope I'm making sense.

 

[slownsteady]

you might find this video helpful, although your hole is a bit bigger:
https://youtu.be/LI7VUyzYA6U

I see one end of the box is resting on framing, is the other end resting on framing too?

 

[thapranksta]

Yeah, the other end will be resting on the frame as well. It isn't in the picture.

 

[nealtw]

You do need solid blocking on both sides every space, Longer screws, screw down thru the wall plate for you blocking against the wall.

 

[thapranksta]

I've gone forward with this project. I opened up more of the subfloor. I planned to put the same subfloor back down in those places since it didn't need replacement but a small layer on top of the I-joists came up when I removed one part of the subfloor and I may have to install a totally new piece for that one. I've got 4'' insulated R6 flexible ducting. I am not sure if I will be able to install all the ducting from the inside of the house as the exit hole seems as though it is not the cleanest job and the mildewed ducting completely extends through the hole. I will attempt to post pictures later.

 

[slownsteady]

We like to hear about progress. Just curious, Why did you stick with flexible pipe?

 

[thapranksta]

I stuck with flexible pipe because it was readily available insulated and it would be easier to try to snake through the existing holes..

 

[thapranksta]

Here are more pics as promised. I have more of a dilemma on my hand now as you will see below. I cut cavities that will allow me to access all the ducting in the upstairs bonus room where it is routed under the subfloor and exits the house.

Picture of fan opening in 1st floor bathroom ceiling (7.5'' x 7.5'')

Pictures of floor cavities and Subfloor pieces removed

This is the end of the line for the venting from the room upstairs where the flexible ducting exits the house. On the other side of the wall at the top of the picture is a tiled bathroom unfortunately and the 1st floor bathroom that the ducting runs from appears right below it.

Seems like I have three options: 1) try to cut a large enough hole in the 1st floor bath ceiling to remove the current fan box and install a new one, 2) try to cut a larger access hole in the I-joist in the bonus room which seems like it could start affecting the structural integrity, or 3) gut the bathroom floor above it, removing the tile and subfloor and creating a much larger project but having direct access to the area above the bathroom fan.

Ugh.

 

[thapranksta]

I went ahead and replaced the duct vent outside. I found that the flexible pipe was screwed directly to the outside vent itself. Later I found out why besides the cost reduction. The hole was much too small for a straight pipe to fit completely through it. I did use a straight pipe after much effort sanding and forcing the pipe through the exit hole. [Someone with a dirty mind might have fun with my wording. lol.] I also found that the vent and end of the flexible piping was home to bugs at one point in time. I suspect rodents might have also been through there.

Now I can't get the vent outside to sit flush with the house because the collar will not fit through the hole. Is there any way to cover this gap and make it look more aesthetically pleasing without renting masonry hole cutting tools.


No way to stop bugs from getting in there.

This came out as soon as I disconnected the vent from the pipe.

Straight pipe inside

Outside - new vent with a flap to keep bugs out and also a pest guard. The gap around it is a little unsightly. I applied caulk but there's no way it could ever reach it.

 

[thapranksta]

I fixed the gap problem with a masonry chisel I went to pick up. I put more caulk behind it. Inside where there are gaps between the straight pipe and wood wall, I plan to put steel wool and put caulk on top of it. Then there will be insulation placed around the pipe as well. I've still got to figure out how to get to the bathroom fan duct connection safely though before I can change out the whole thing. A small victory in the grand scheme of things but a victory nonetheless.

 

[nealtw]

You have a smooth ceiling in the bathroom, you could just cut a bigger hole in the drywall and patch after the new fan is installed. Sorry for the delay I missed your posts.

 

[thapranksta]

It pays to measure instead of "eyeballing". I discovered I did not need to worry about ripping up the bathroom on the other side of the wall. I found that the bathroom fan was actually located over a hallway leading into an upstairs bedroom.

BINGO!

Duct's Route over 1st floor bathroom ceiling

Uninsulated, mildewed duct removed

Flexible 4'' R6 Insulated Duct (Replacement Candidate)

Now I've got some more decisions to finalize. Do I need to worry about using a hangar over the plumbing in the bathroom ceiling or could I just lay insulated duct right on top of it with no problems? Is the insulated flexible duct really the way to go or would rigid uninsulated duct really be best?

 

[buffalo]

A straight peice of flexible duct , compared to a rigid duct the same length , has 5x the restriction. At the same time a rigid uninsulated duct could condensate. I would be more worried about condensation so long as the fan is adequately venting the room with the flexable. I guess insulated rigid would be the best , but maybe that's just overkill?

I'm wondering , is that insulated duct you posted going to fit through the existing holes in the lumber? Also , I could be wrong but the white flexible duct is what I have seen used for exhaust fans and dryer vents , the flex you posted is what I see for hot air supply ductworks. Thier may or may not be a differance , but I'm thinking thier is.

 

[thapranksta]

The flexible insulated duct does not fit into the existing holes without forcing it through. I would have to enlarge the holes in order for it to fit without restrictions.

 

[oldognewtrick]

Get a couple of metal 4" 90* elbows to go through the existing hole. Attach the flex to them and pull the insulation over them and secure with sheet metal screws.

 

[slownsteady]

Just letting the duct rest on the drywall ceiling is probably not going to cause any issues. It is a better choice than tying it up with string. If you want to support it off the drywall, you need to find a wide base to rest the duct on. And you want to avoid the dips and sags between the supports. You could staple up something like chicken wire or some kind of fabric to act like a hammock for the duct, but by the time you factor in the extra labor and the cost of the materials, you can see why rigid ducts have an advantage.

 

[thapranksta]

In terms of rigid duct, is PVC as good as metal?

 

[buffalo]

Bassett hangers , they are telescopic and you nail them into the joists.

In all honesty , your over killing it. Get more 4" round white flex and rerun it.

 

[slownsteady]

Bassett hangers , they are telescopic and you nail them into the joists.

In all honesty , your over killing it. Get more 4" round white flex and rerun it.

I'd rather use string than pay $30/per for a support that won't solve anything.
But after all this, Buffalo makes a point: this isn't a dryer vent that's subject to lint collection, and a 4 inch duct should supply enough air flow, even if it's not perfectly straight.

 

[buffalo]

I'd rather use string than pay $30/per for a support that won't solve anything.
But after all this, Buffalo makes a point: this isn't a dryer vent that's subject to lint collection, and a 4 inch duct should supply enough air flow, even if it's not perfectly straight.

Yea , you can buy those hangers from an hvac shop cheap. It was just a link to show what's out there , not the best price. I would never buy anything hvac from a big box store , 4x the price.