roof vents for dryers and exhaust fans

[Rewired]

My girlfriend recently moved into the upstairs of an older house that was set up from day one to have a little apartment or inlaw setup on the top floor. (kitchenette, full bath, no laundry)
The landlord is going to get one of those "stackable" washer dryers and put it in the closet as there is the proper plumbing connections nearby, BUT the only option to vent the dryer is up through the roof, which should be no problem at all. My girlfriend also wants me to add an exhaust fan in the bathroom and one in the ceiling of the kitchen ( Not a hood fan over the stove, that is impossible to do in this situation).

My question is: Is it possible or allowable to vent everything through one large common vent through the roof instead of cutting 3 separate holes for each device, putting dampers on everything to prevent backdrafting? Or if anything, combine the two exhaust fans into one common vent and have the dryer go up through the roof on its own?

Just Curious..

A.D

[lonestarheir]

Possible of course - advisable no. You can vent the bath fans into the eave of the house, and vent the dryer through the roof. That would be the easiest way, and would pass code (at least in Texas). You can even just vent the exhaust fans in the attic space.

__________________________________________________

Brandon
- Have you changed your filter this month? -

[LazyPup]

I would check both the Dryer installation specs and your local codes for dryer vents. Going through the roof may prove to be too much vertical head and the dryer air flow may not be sufficient to properly carry the solid particulates of lint which are present in the dryer exhaust.

Normally dryers are limited to 8' to 10' of vertical rise.

The common plastic or aluminum flex ducting has a very high resistance to flow, therefore I would keep the length of flex as short as possible and use metal duct with the joints taped together rather than screwed. (When its screwed together the tips of the screws extending inside the pipe tend to catch lint and can cause a clog.)

If your local code will permit it you may want to consider using sched 40 PVC for the ducting. Run it vertical into the attic space then use a long radius 90 to transition from vertical to horizontal and extend out a gable end or a soffit with a standard dryer vent. You would need to support the PVC with a 1/4" per foot pitch toward the outside vent so that any condensate moisture that forms in the pipe would run out.

[Rewired]

Thank you all for the information and the suggestions!
I have thought about going out the gable ends but I think its too far to pipe. ( washer / dryer is going to be dead center of the house)... I don't think its going to be more than 8' from the dryer outlet to the roof.. I will have to see the specs on the dryer to see where I can go with it and how far.
As for the exhaust fans I will have to see if I can get them out of the soffit, well one of them anyway. Next other option other than the roof is the gable end... In Canada, unfortunately its FORBIDDEN to exhaust bath fans and the like right into the attic.. True it happens and goes un noticed by the inspectors, but in no time you end up with a moldy attic , rotten wood and soggy insulation!

A.D