# drywall over P&L ?



## oldrivers (May 2, 2009)

yes you can do that , but take an awl and hammer and try finding the joists . most likely 16 on center but not always the case . run the sheets perpendicular to the joists as usual but try to hit the joists with the fasteners and not just the lath thats about it .


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## oldrivers (May 2, 2009)

you can also drill holes in the walls and use blow in insulation if you wish.


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## Fix'n it (Mar 12, 2012)

thanx. yeah i plan to nail to the rafters. but i am wondering if i should use some kind of vapor barrier.

i am not going to blow in the walls. that is coming down. i actually started 1 room today. 1 reason for the p&l to come down is updated electrical and new framing for the new, different sized windows i am getting.


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## joecaption (Nov 30, 2011)

It would be far better to also remove the plaster on the ceiling.
If for some strange reason you deside to leave it do not even think about using nails, use 3' sheetrock screws instead.


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## Fix'n it (Mar 12, 2012)

removing it is not going to happen. i would rather leave it as is, than remove it. 

screws, yeah. idk why i said nail.


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## M3 Pete (May 10, 2011)

Do they recommend a vapor barrier where you live? I have heard of using spray foam as a vapor barrier in an attic where none exists (probably like your P&L), but I'm not sure how that would play out with an added drywall layer. 

And given what a PITA it would be to clear out all your insulation to spray foam, plus you likely need insulation on top of the foam, you might as well remove the P&L ceiling. How much more mess could it be when you are knocking down the walls?


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## Fix'n it (Mar 12, 2012)

M3 Pete said:


> Do they recommend a vapor barrier where you live?
> 
> How much more mess could it be when you are knocking down the walls?


idk. i am trying to find out. but like you said = how would that react with P&L throw in the equation . 


a TON !!! we are living here. and with a job(for now) i can do only so much at a time. i can't shut down half the house for weeks to do that. i just did a small area of a wall in an unused room, and the wife was complaining, i left it a bit messy. she didn't like that. i had to nicely tell her to stfu or do it herself.

thanx for the reply


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## M3 Pete (May 10, 2011)

Fix'n it said:


> i had to nicely tell her to stfu or do it herself.


I'm sure that went over well. :laughing:


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## johnzenobia (May 6, 2012)

You can go over the old p&l I would not take it own if you don't have to. Couple questions. 
How is the electrical run. If any in the ceiling. Don't use too long of a screw or you may hit a water pipe or wire.
What is directly above that room? If old bath room with cast iron tub you may want to tear ceiling out and beef up joists from the weight.
Other than that I wouldn't take out the ceiling because it can open up Pandora's box. That old rough cut lumber is exactly what the name says rough cut and not plum. The old plaster can be 1/4" thick in some areas and 3/4" in others because of the framing. Good luck


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## Jay 78 (Mar 2, 2011)

Fix'n it said:


> i have 9" ceilings.


:huh:



joecaption said:


> use 3' sheetrock screws


:confused1:


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## Fix'n it (Mar 12, 2012)

M3 Pete said:


> I'm sure that went over well. :laughing:


she knows not to argue with me. but saying that,i am not a dictator. 
when i was a teen, i decided to help my dad paint the house. i was doing it right, and kinda quick. he told me i was doing it all wrong(i was doing it the way he was. i was watching him). i set the paint brush down and walked away. i never helped again.



johnzenobia said:


> You can go over the old p&l I would not take it own if you don't have to. Couple questions.
> How is the electrical run. If any in the ceiling. Don't use too long of a screw or you may hit a water pipe or wire.
> What is directly above that room? If old bath room with cast iron tub you may want to tear ceiling out and beef up joists from the weight.
> Other than that I wouldn't take out the ceiling because it can open up Pandora's box. That old rough cut lumber is exactly what the name says rough cut and not plum. The old plaster can be 1/4" thick in some areas and 3/4" in others because of the framing. Good luck


all of the K&T is being replaced. so no issue there. there is an empty attic up there. 


Jay 78 said:


> :huh:
> 
> 
> 
> :confused1:



:laughing: some typos there, A


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## Fix'n it (Mar 12, 2012)

here is where i am at in the "learning" room. this is about 2hrs work. this is going to be our temp bedroom, while i do thee bedroom. otherwise its just a storage room. a new window is going in, once i decide what to get.


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## Fix'n it (Mar 12, 2012)

oh. the P&L on the interior walls. i am just going to drywall over em. call me lazy, but screw that tearing out all that chit. 
and there was no insulation in that wall.


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## user1007 (Sep 23, 2009)

Just remember you will have to get extenders for your electrical boxes and existing wiring will need to be long enough to reach into them. You cannot splice length on and meet code.

You did say you are pulling new wiring though?


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## rditz (Jan 6, 2011)

Fix'n it said:


> oh. the P&L on the interior walls. i am just going to drywall over em. call me lazy, but screw that tearing out all that chit.
> and there was no insulation in that wall.


I am renovating an old farm house and gutted the section that i was working in.. we reclaimed about 2" in each direction because we removed lathe & plaster and then each exterior wall had 1" thick boards. wall cavities filled with dirt... a huge mess, but it is clean, warm and i have outlets and lights where i want them.. 

IMHO, gutting it and starting fresh is always the way to go..


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## AllanJ (Nov 24, 2007)

Some really old homes used dirt for insulation in the wall stud cavities. I would question whether this weighed so much that the lath separated in places or maybe sections of wall collapsed outward.

But another explanation for dirt in the wall stud cavities could be animals nesting in there, in which case the dirt would be hazmat.

Because of weight I would also think twice before drywalling over the ceiling, over existing plaster/drywall and all.


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## Fix'n it (Mar 12, 2012)

AllanJ said:


> Some really old homes used dirt for insulation in the wall stud cavities. I would question whether this weighed so much that the lath separated in places or maybe sections of wall collapsed outward.
> 
> But another explanation for dirt in the wall stud cavities could be animals nesting in there, in which case the dirt would be hazmat.
> 
> Because of weight I would also think twice before drywalling over the ceiling, over existing plaster/drywall and all.


dirt in the walls, interesting. but i bet it worked, to some degree.

i thought about the weight. while i think it can handle it, i have been thinking about a drop ceiling or something. i just want something better than the ugly P&L.


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## johnzenobia (May 6, 2012)

Dirt for insulation? That is a good one. There is dirt there however it isn't insulation nor was it put there on purpose for insulation. That is the funniest thing I have heard in a long time. Lol


QUOTE=AllanJ;922604]Some really old homes used dirt for insulation in the wall stud cavities. I would question whether this weighed so much that the lath separated in places or maybe sections of wall collapsed outward.

But another explanation for dirt in the wall stud cavities could be animals nesting in there, in which case the dirt would be hazmat.

Because of weight I would also think twice before drywalling over the ceiling, over existing plaster/drywall and all.[/QUOTE]


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## kj6887 (Feb 19, 2012)

Also remember that you will have to extend your door jambs on your interior doors.


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## rditz (Jan 6, 2011)

johnzenobia said:


> Dirt for insulation? That is a good one. There is dirt there however it isn't insulation nor was it put there on purpose for insulation. That is the funniest thing I have heard in a long time. Lol


agreed.... it wasn't very good for R value, but it did insulate against noise during bad weather... 



> i have been thinking about a drop ceiling or something. i just want something better than the ugly P&L.


 will say again, gutting it IS the proper way to go.


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## Gary in WA (Mar 11, 2009)

We can help you figure the drop ceiling or not......plaster and wood lath is 8# per sq.ft., it adds up quick on 2x4's that are over-spanned to begin with- check here: room above; http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_5_sec002_par017.htm

attic above: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_8_sec002_par023.htm

As you said vapor barrier, I presume attic above?

Gary


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## sevenlol (Aug 8, 2011)

i had a similar situation. 9' ceilings, p&l everywhere. took out all the walls for insulation and new wiring (interior too as i changed the arrangement a bit).

chose to leave the ceiling and just rock over it. had a drywaller friend do it, i believe they used the 1/2in ultralight and screwed on the 24oc joists with 2 1/2 screws. they put a knockdown texture on it as well. it's 18months later and there is no sagging, and the ultralight doesn't add all THAT much to the total weight. looks great.


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## oldrivers (May 2, 2009)

vapor barrier between the plaster and drywall ? i would say no because you might create a vapor lock between the two which would trap moisture , cold above - hot below creates moisture i would let it breathe .


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## Ravenworks (Oct 31, 2010)

I would go over it with 1/4" and texture the ceiling.


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## sevenlol (Aug 8, 2011)

isn't 1/4 more expensive (and prone to sagging)?


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## Ravenworks (Oct 31, 2010)

sevenlol said:


> isn't 1/4 more expensive (and prone to sagging)?


You are going over the P&L right ?
Glued and screwed why would it sag?
When they did our hobby farm 30 years ago that is what they used,still looks as good as the day they installed it.
3/8 maybe?
What ever you choose go to a "REAL supplier" and ask questions,your main concern should be weight.
Seal up the room with duct tape and plastic including the floor,send wifey shopping and have at it,toss the demo out of the window.


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## johnzenobia (May 6, 2012)

Just use 1/2 or at the very least 3/8. 1/4 will be a total pain getting on the ceiling and will probably crack while trying to install. 1/4 will sag if your on 24 inch rafters. You can put a plastic vapor barrier up however its a bit extreme.


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## Fix'n it (Mar 12, 2012)

thanx, everyone. i have time to think about this. idk what i am going to do yet.


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## meanindirectory (May 19, 2012)

I also think that it is a bit more expensive.


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## bjbatlanta (Jul 16, 2008)

Use adhesive and nails/screws when adding a layer over plaster. 3" screws are a bit of a stretch (unless you have 2" of plaster), will be expensive, and will be a pain to use. Consider new construction. Standard is 1-1/4" screws or 1-3/8" nails. Roughly 3/4" penetration into the framing lumber. Most plaster and lath is 1" thick (nominally). If you're using 1/4" rock, 2" fasteners are fine.....


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## bjbatlanta (Jul 16, 2008)

And I definitely wouldn't tear out any ceilings unless absolutely necessary


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## Fix'n it (Mar 12, 2012)

oh, believe me. i DO NOT want to take the ceilings down. the main reason i asked about going over it is = will it cause any issues ? like mold or whatever.


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## bjbatlanta (Jul 16, 2008)

It's done all the time. Shouldn't be any issues.


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## Fix'n it (Mar 12, 2012)

ok, thanx. i am looking for a used drywall lift on craigslist. 

any tips on locating the ceiling joists ?


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## bjbatlanta (Jul 16, 2008)

I'm assuming this is a first floor where you can't get in the attic and get an idea where to start. The joists SHOULD be running the shorter direction of the room size. I take a nail (8d, 16d, whatever you have on hand) and come off of the wall (parallel to the direction the joists are BELIEVED to be running) a foot or so and start "searching". Drive the nail in. If you don't hit anything, move over about an inch or so (either direction) and try again. Keep on until you hit something solid (wood). Measure over 16" and see if you hit something solid again. If not try 24". Basically, you're going "fishing" and hopefully the joists are on some kind of pattern. You really need to find each individual joist! Sometimes in older homes, they may not necessarily be on any certain centers. Be sure when you hit wood to find both sides of the joist (keep driving your nail on both sides until you hit "air". Make mark in the center of the joist. Go to the opposite end of the room and use your measurements to find the first joist on that side. Repeat the procedure to find the centers on that side too (things could be out of square). Chalk a line from one side to other on the center of the joists and you're good to go. If it was a sheetrock ceiling you're going over, once you find a joist you can use a "keyhole" saw to jab into the board, saw until you hit wood, then move over 3/4" to figure out the center of the joist....


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## Fix'n it (Mar 12, 2012)

thanx. but i can get in the attic. i am thinking i will drill holes next the the joists, from in the attic.


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## bjbatlanta (Jul 16, 2008)

That's your best bet since you have access.


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## M3 Pete (May 10, 2011)

If you drilled from the attic, next to each joist at a 45 degree angle, the exit holes should be pretty close to the center of each joist.


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