Hi Folks, I’ve got a head-scratcher for you.
We just moved into a 20 year old condo. Among the things that we intend to replace is the upstairs bathroom vent fan. It works, sorta, but is obnoxiously loud. The problem is that there is no attic or crawl space. Just joists and a flat roof – the vent pipe turns and runs up through the roof. All the retro-fit bath fans that I’ve seen are designed to be attached from above. Fins to nail into the joists or bars to fit between joists and a place to attach the vent pipe after the unit is installed.
Does anyone know of a unit that installs in the old hole in the ceiling from below (I can Sawzall the old unit out of there) without chopping a great hole in the sheetrock to be patched later?
Other than that, Mrs. Lincoln, how did you enjoy the play?
Tim
Replies
Look at the Panasonic line of bath fans. They can easliy be installed from inside the bathroom. Just remove old fan, leave the duct in place though. Make the hole to the size of the new fan. Install the duct on the supplied duct bracket, screw that bracket into place per the instructions. Connect the the wiring. Then install the fan housing box against the duct bracket. Install the fan into the fan housing and then install the grill. This should take about an hour or so. The Panasonic fans run just over a $100, but they are very quiet and very good. I just installed one in my bathroom remodel and bought another one for my other bathroom.
Dan
"Life is what happens when you are making other plans." - John Lennon
Thanks, Dan. I'll check it out.
Tim
Why is it making noise?
If it is just an unbalanced fan or worn bearings on the motor your best bet may be to get a replacement motor. Some of these come with a plastic blower, in case your old one is damaged, or not if it is just the motor. Take the old motor and blower out to get a replacement. Big box hardwares, electrical or AC supply houses are all possible sources. Around here all of them carry the most common sizes that fit most units.
If the exhaust fan housing is rattling you can replace the entire unit or try quieting the existing one. The later can sometimes be accomplished by applying foil tape to the stabilize any loose pieces. Remove the cover, the blower and motor to gain access.
Also I have found that foaming the attic space around the unit, drilling quarter inch holes around the outer perimeter of the ceiling, a bit of spackling to close the hole but no hardship as the cover will overlap any imperfection. Spray a little water up the holes before foaming as this makes the foam grab the moist surfaces and harden quicker. Amazing how well a can of foam and a little aluminum tape can tighten and deaden a fan housing.
If you want to replace the entire unit, possibly to increase the CFM or to get to a level of quiet not possible with your present unit this to is possible. No big deal, usually. First select a replacement unit as big or bigger than the one you are replacing.
Next remove the old unit. Odds are it is nailed or screwed into a joist but with a bit of judicious prying and jimmying the old unit will loosen and come free. Don't try to pull it down as your likely to damage the ceiling. Once loose within the space above the ceiling You should be able to swivel it around to take it out. Once down, or working within the available space you should be easy to disconnect the flexible duct and the power connection. Don't forget to turn off the power.
Typically on the new fan you will need to fold the side wings to allow the unit to fit into the square or rectangular hole. No worries. If you wish to be fancy about it a piece of rubber, sold as gasket material, or ice barrier placed between the fan housing and the joist can help keep the unit quiet.
If the new one is larger than the old one you need to hold the unit up and trace the outline. Remember that you need to gauge it against the joist. Once marked cut the ceiling as needed. Once the hole is cut. You transfer over the duct and wiring. Sometimes this is easier with the unit stuffed into the hole. Depends on where these appendages emerge in relation to the joist.
Once you get the duct and wiring in to the new unit go ahead and check to make sure the unit runs and the duct doesn't come off. Nylon ties work well on flex duct. Foil tape, small self-drilling screws and harsh language help with rigid metal ducting.
Once the unit is together mount it by running screws from the inside into the joist after removing the fans motor and blower. Note how the blower fits. You want to install screws where the blower will not touch them. Note that on some motors the blower will shift as the unit starts and takes up the slack, often 1/4" so beware. Try to get the screws in square and it pays to recess the housing slightly into the ceiling.
Wide thread drywall screws, Piffins, will work but deck screws are what I use. one to one and a quarter are long enough. It sometimes pays to use an awl to punch holes as this makes placement more positive and stops skating. You could drill small holes but I usually do this without power tools and I have an awl on my belt.
If the joist wasn't to slanted the fan should be pretty square and the cover should cover the unit and touch the ceiling all the way around. If the unit hangs down a bit, the cover should cover anything shy of 3/16" or so, oposite the joist side you can install old work 'F' clips with the wings bent out. Force into the slot between the housing and the ceiling and the wings should spring out into the open space above the plaster. Push the housing up and fold over the tips to hold everything in place.
Major slants need shims added under the mounting between the joist and the housing. Loosen all the screws and remove the bottom ones. Shove in some shims and tighten. Replace the screws. Check and modify what you have until it hangs right. Just close enough for the cover to go on and fit flush.
If you try the unit and it vibrates you can try putting on a few pieces of ice barrier to deaden the sheet metal and possibly foaming the outside of the unit, as described above. Have fun and be careful.