November 6, 2004 Radio Show Joe: Hanging Mirrors on Plaster Walls (Savannah, GA)
Tim: Travis and I were just talking off the air, and Annetta, the three of us. We can't talk to Carey because she's behind two layers of glass in the newsroom, but anyway, she might be hearing it. So, we were talking a
little bit about The Mansion and all at once Travis asked
me, `Gosh, has it opened up any other opportunities for you,
and what about TV?' bla, bla, bla. And I was just telling
him that, at this point it really kind of hasn't, but I'm
not worried about it.
The problem with television is that it requires an enormous
amount of time. You'd be shocked at how much time it takes.
Well, I'll give you an example. If you've watched the
mansion episodes now and you see how much I'm on screen,
maybe three minutes out of the 47 show us judges. Each time
I was there, it was a minimum of five hours. So, it takes so
much time to film stuff, you'd be shocked. Even the things
that I do each week for Channel 5 here on WLWT, those 90-
second vignettes. On average it takes about 40 minutes to
get 90 seconds, so enormous time commitment. The only way
that I would do it is that financially, they'd really,
really, really, really have to make it worth your while.
Plus, you know, kick in a perpetual residuals, because to
sit there and trade money for time or time for money, that's
not the way to go.
Okay. Let's go back to the phones. Boy, we've got them
stacked up. Joe, it's Tim Carter. Thanks for calling WGRR.
It's great to have you on the air.
Joe: Hi. Good to be here. Thanks for taking my call.
Tim: Not a problem. How can I help you, Joe?
Joe: I am helping a friend with a wonderful old house in
Savannah.
Tim: Okay.
Joe: We have to hang some fairly heavy mirrors in plaster
walls, and I've not dealt with plaster walls. My hardware store locally sold me the same type of fasteners that you use in sheetrock and it doesn't work the same, and I'm
afraid to proceed because I don't want to crack up all the
walls. They seem much harder.
Tim: Well first of all, what I want to know is do you know
what is behind the plaster? Was the plaster put over solid
masonry, like a brick wall, which is common in many, many
old homes? OR is it an interior? Even interior walls can be
solid masonry. But is it a frame wall where they had some
old 2x4s that they might have covered with wood lath? Do
you know what that wall's made of on the other side of the
plaster?
Joe: No, I don't think it's masonry, though.
Tim: Is it an outside wall or is it an inside wall?
Joe: It's an inside wall.
Tim: Inside wall. How thick is the wall? Do you have an
idea? Meaning, you know how right now in a new home, we'd
have like a 2x4 wall, which is basically about 4 1/2
inches thick? Because you've got the 2x4 covered with 1/2
inch drywall on each side? Can you tell, because of an
adjacent doorway that's going through this wall, how thick
it might be?
Joe: I haven't really looked at that. The house was built
in the 30s.
Tim: Okay. Well anyway, here's...
Joe: But I can experiment inside a closet.
Tim: Sure! Sure you can. What's the outside of the house
made from?
Joe: Brick.
Tim: Brick. Okay. And you think it was built in the 1930s.
Joe: Right.
Tim: Okay. I would venture to say that if this is an inside
wall, what they probably did is that it has what we call
plaster lath on it.
Joe: Uh-huh.
Tim: Here's how they used to build old plaster homes. They
would take what we call wood lath, and they would have a
carpenter come in and they would nail up those tens of
thousands of strips of wood, putting a space between them.
And then the plasterers would come in and put on their first
coat of plaster, and it would ooze through those cracks in
the wood. You know, the spaces between each piece. Well, it
was really, really labor intensive to put all that wood up.
So, back in the 20s and 30s, the plaster companies came up
with, actually this was the first drywall. It was pieces of
drywall that were 3/8 inch thick. They came in sheets 16
inches wide by 4 feet long. Sometimes they were 32 inches
long. And they discovered that they could nail this stuff up
much faster and cover an entire room in maybe 1/20th of the
time it would take a guy to nail up wood lath. Okay?
Joe: Uh-huh.
Tim: So! And then they would just put their plaster right
on top of that. And it's very solid. In other words, houses
that have this plaster lath board up and then the coating of
scratch plaster and the white coat, boy, it's hard. I mean,
you tap on that wall and you think, `Gosh, this is really,
really solid!'
Joe: It is hard.
Tim: Yeah, exactly. And you can test this if you want.
Here's one thing you can do. You already know where you're
going to put this big mirror up, right?
Joe: Right.
Tim: Okay. You can actually take just a masonry bit. Put a
drill and put maybe a 3/8 inch bit that, you know, it has
that masonry carbide tip on it?
Joe: Uh-huh.
Tim: And I know this sounds nuts, but right where the
center of the mirror's going to be, and this mirror's going
to be what, like 3 feet wide by 4 feet high or even bigger?
Joe: Tape was bigger.
Tim: Okay. So what if you drill a 3/8 inch hole in the
wall, right? Because we can patch that, right?
Joe: Right.
Tim: Okay. Drill a hole into the wall. I know it sounds
nuts. You're going to think, `Why am I drilling this hole in
the wall?' All I want you to do is I want you to figure out
what's behind the plaster.
Joe: Uh-huh.
Tim: Okay. Once you bite through that coarse plaster, if
you do have plaster left, you're going to go right through
it. Well, once the drill bit penetrates, be careful. Don't
push it really hard because I don't want you to hit a water
line or a drain line or an electric wire. Okay?
Joe: Right.
Tim: But at least now you're going to know what the wall's
made of, and if it's hollow space, because it's a wood frame
wall, now you've got some options. Here's what I would do. I
would use a French cleat to hang this heavy mirror. I've got
an article on my website kind of describing this. If you go
back to askthebuilder.com, I think this might be under the
category of accessories or specialty accessories and
miscellaneous, or it could be under projects on the left-
hand side. But you can use the search engine and type in
decorative shelf (in the search engine) and learn how I hung
this little decorative shelf using a French cleat. Let's say
that this wall is a wood frame wall. You're going to
determine using a stud finder, or the old traditional way of
just hammering a nail through the wall, you're going to find
out where the studs are in this wall...
Joe: Uh-huh.
Tim: And you're going to attach the 1/2 of a French cleat
to those studs, using some 2 or 3 inch long screws, and then
you're going to attach the other half of the French cleat to
the mirror, and you're going to mate those two pieces
together and that mirror's not going to go anywhere. I would
be really, really cautious about hanging a heavy mirror
using any type of a hook that's just driven only into the
plaster. See what I mean?
Joe: Right.
Tim: And the odds of you finding a stud that's on the
centerline of the mirror is like one in a thousand. See,
that's the problem.
Joe: Right.
Tim: Because you know where you want the mirror to go and
you know exactly where the centerline of that is, if you use
the wire that's sometimes behind the mirror?
Joe: Uh-huh.
Tim: Well, that means that you've got to have a stud right
there at the center. Well, that's not going to happen. So,
that's why you use a French cleat. All right?
Joe: Okay.
Tim: So, go to my website, find that column about
decorative shelf. If you don't understand it, send me
another email, okay?
Joe: All right. For the fairly light pictures, you could
probably do something right in plaster.
Tim: Right. I would say anything that weighs less than 30
pounds in plaster, even if it's a hollow wall plaster, you
can use a traditional anchor and put a little hook on it and
it's going to hold. You'd be shocked how strong plaster is,
but that mirror could easily weigh, what, 80, 90 or 100
pounds?
Joe: Right. This one's heavy.
Tim: Yeah.
Joe: But I'm just going to have to drill instead of tapping
something because it's so hard.
Tim: That's right. And like I said, I really want you to
use a French cleat on this, because I'm telling you, you
don't want...
Joe: Oh, I will. I will on the mirror.
Tim: Yeah. But a regular, smaller picture or whatever, no
problem. You'll be able to go right through the plaster with
a nail.
Joe: It's got to be a masonry bit instead of a regular bit.
Tim: What will happen is if you use a regular wood bit to
drill into that plaster, you're going to ruin the bit;
you're going to dull it up, because you're got to remember,
plaster is actually, it's just concrete. It's got a
compressive strength, if it's made right, of about 3,000
psi. So, when you start drilling into that brown coat,
you're just drilling into cement and lime and sand. I mean,
you'll just really dull up a wood bit. I just wouldn't
recommend it.
Joe: Okay. Well, thanks so much for your help.
Tim: Well, thanks for calling me!
Joe: Okay. Bye.