Patching around bathroom exhaust fan?


Old 12-06-16, 01:36 PM
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Patching around bathroom exhaust fan?

Hello; I'm a total noob to DIY, but managed to install a bathroom fan in my 1950's all-plaster house(hooray!).

I cut the ceiling hole too big, and want to patch the plaster around it, but it appears there's drywall backing the plaster, as opposed to lathe boards. Here's a pic looking up at the ceiling:

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I don't want to cut the hole all the way to the other, left-most joist since it will make my problem even bigger, unless that's absolutely necessary. I also don't want to have to remove the fan, if possible.

I can't score the plaster, since there's no lathe to attach it to and I'm out of my depth....can anyone offer advice?

Last edited by keylarg; 12-06-16 at 01:56 PM.
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Old 12-06-16, 02:23 PM
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Welcome to the forums!

Can you insert a piece of wood longer than the hole and secure it with screws [thru the drywall/plaster]? If so, I'd attach drywall to that board and then use a setting compound like Durabond to make the repair.

It's a little hard to tell from the pic but you'll probably want to 'square up' the cut drywall so you can fit the new piece of drywall in nicely. Once the repair is done you'll want to texture it so it blends in with the rest of the ceiling.
Old 12-06-16, 02:53 PM
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Thanks for your reply!

When you say "secure the piece of wood" with screws, do you mean downward from inside the attic?

Unfortunately, the fan duct exits out the upper-right side of the picture, so I can't really put a piece of wood-backing directly above the hole (unless its less than .25" thick)
Old 12-06-16, 03:11 PM
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You also need a piece of wood on the side of the fan....away from the ceiling joist.... to hold the side up tight to the ceiling.

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Old 12-06-16, 03:18 PM
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Use these drywall repair clips:
Wal-Board Tools Drywall Repair Clip (6-Pack)-54-014 - The Home Depot

Cut the hole square and secure the clips by screwing up through the ceiling.
The clips are basically tiny backers and are predrilled for screws.
Old 12-06-16, 05:46 PM
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I don't think the bullfrogs Handyone linked to will work very well. The lath and plaster are too thick. Yes, it is lath. If you can hold the frogs in place without the little clips they might work. Then most any piece of drywall will be suitable backing for quick set joint mud. It might take more than one coat to fill it out flush.
Pjmax is right about some support on the left side. You might be able to use some plywood slipped in from one end if you make the hole at the top of the picture a little larger and square it off. Screw the plywood on the finished side through the lath and plaster and let it touch the side of the fan box and then screw the fan box to the plywood. What you are doing is using the lath and plaster to hold up the plywood to hold up the fan. Not the best way of doing it but probably the best you can do without removing the fan. All of this would be easier if you removed the fan but you will have to decide if the ease of the plaster repair warrants the removal and reinstallation of the fan.

This is a simple fix if you just get some support up there.
What is the black stuff in the hole at the top of the picture?
Oh and you asked about screwing from the bottom up or top down. Yes bottom up. The screw will pull itself through the plaster. Don't let it pull too far -- just so it is recessed.
Old 12-07-16, 07:12 AM
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Thanks.....It isn't clear from the pic, but the upper-left-side does have a bracket (built into the fan housing) that is screwed directly to the joist in the attic; it doesn't have any give/play when I press on it. The upper-right side had some give, but I fixed it by screwing the housing flange to the joist, like in this pic:

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I think I will try getting a piece of blueboard, squaring off the hole, then using the drywall repair clips. If that doesn't work, I can always increase the hole size until it gets to the joists, then put a big piece of blueboard across the whole "field" between the two joists.

Btw, the black stuff is just a pillow case I stuffed in there to prevent attic insulation from falling into the bathroom
Old 12-07-16, 08:57 AM
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While the hole needs to be cleaned up, there is no need to enlarge it to expose a joist. Take a piece of lumber 3"-4" longer than the hole and insert it so you can put a screw it in thru the drywall/plaster on each end. You'd then screw the patch piece to that piece of wood.

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