Installation on Plaster Walls

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Kirstie

Kirstie

PFG, Picture Framing God
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Jan 16, 2007
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Berkeley, CA
Not to jump the gun, but reading Rob's class descriptions made me think of a question I need a good answer to now. We have a lot of houses in our area with old plaster walls and no crown moulding to install moulding hooks from. What is your best recommendation for hanging hardware for plaster walls? Brick? Drill, plug, and screw?
 
Kirstie,

On old plaster, I start with the Floreat hangers; if I'm then having problems I'll go to some of the other methods; sometimes even butterfly type wall anchors. Even in the same structure, it can vary from wall, or even location on the wall.
 
Regardless of the type of hanger used, one thing is very critical: you never ever hammer anything into a plaster wall. Not only will you damage or crack the plaster wall itself, but more importantly you may break the plaster keys of the wall.

For those unfamiliar with how a plaster wall is made and held together first look at this damaged wall.

Small_CloseUp_NoPlaster.jpg


See how the lath (the small horizontal boards) is spaced with gaps in between. When a wall is plastered, something needs to hold the plaster in place. When the plaster is applied, the plaster seeps between the lath and expands. The portion behind the lath is called the key.

3744878550_fd08b1f307_o.gif


If the keys are broken or cracked, then the wall will start to fail. And when a plaster wall starts to fail, your work is cut out for you. I bought an old house this year and spent quite a bit of time repairing walls with broken keys.

But that is irrelevant except to note that any hammering of a plaster wall may break the keys and lead to serious repairs in the future.

So now back to the original question. How to hang a picture on a plaster wall? Very carefully. Sorry couldn't resist.

I also use the floreat hangers. I place the hanger against the wall where I want it to reside and then drill a hole using the hole in the floreat to drill at the proper angle. I use a drill bit that is very small that will fit in the hole in the hanger and is about the size (but no larger) of the nail. I put the nail in gently after I drill a hole. I use a small tack hammer and gently tack it into the hole.

Done properly, you won't damage the wall.

I am curious as to what methods other use when there is no picture rail.
 
United sells the brass hangers which have the proper steel nails for plaster walls. The nails are the ones with the brass heads on them so if it needs to be removed you twist them with your fingers to pull them out. I grew up with plaster walls and spent many years installing framing on them.
 
Larry Peterson said:
I also use the floreat hangers. I place the hanger against the wall where I want it to reside and then drill a hole using the hole in the floreat to drill at the proper angle. I use a drill bit that is very small that will fit in the hole in the hanger and is about the size (but no larger) of the nail. I put the nail in gently after I drill a hole. I use a small tack hammer and gently tack it into the hole.
Click to expand...

I cut the head off the nail and use the nail as a drill bit.
 
Wow, Larry- at first I thought you had a copy of the PowerPoint I use for the class as I have almost the exact same photo and diagram. Thanks for posting it.

I agree with almost everything that has been posted except I CANNOT RECOMMEND THE USE OF FLOREAT (type) HANGERS.

Larry is spot on. The majority of damage/failure to lath and plaster walls (note that I say lath and plaster walls as modern plaster does not use lath and you do not have the same problems) is from the keys breaking (or having already been broken). DO NOT POUND NAILS INTO LATH AND PLASTER WALLS.

An installer can break keys but the symptoms may not manifest themselves for years. In an older home, one does not know what was hung (or attempted to be hung) before nor can one see the keys or the condition of them. Age can also cause bond failure between the plaster and the scratch coat.

If the keys are broken, there is nothing supporting the scratch coat and the weight of a newly hung picture could be the proverbial "straw that breaks the camel's back" - the stress of the weight of the picture could be all that is necessary for the scratch coat and surface plaster to pull the plaster off of the lath. In CA, earthquakes can cause this to happen years later.

100% of the failures that I have seen have been when a Floreat type hanger has been used. The problems I see are two fold. One is that the nail is tempered blued steel. If the head is struck at an odd angle, the nail may develop stress cracks and will eventually fall off. I have seen this many times when we have been called into a home and the hanger is there just supported by the stumps of the nails with no heads.

Another problem is that the uncoated nail reacts with the lime in the plaster and corrodes making a rust spot or dissolves to the point of failure.

The last problem - and why I just won't use these hangers, is that to increase the holding power of these hangers, the same size nail is used in greater quantities. The problem is that if you have a weakened area of the wall, you are just exaserbating the problem by giving the hanger and picture more grip to pull the wall down.

The nails are very short. Sometimes shorter than the combined thickness of the plaster and scratch coat and the nail itself may never penetrate the lath itself - or may actually go into the space between the lath (meaning you have actually drilled through the keyways.) and you are relying on the density of the scratch coat in the key to support the shear weight of the picture. Not so much of a problem with lighter pictures, but a potential failure for a larger picture, especially if you only use one hanger and a wire to hang.

I also can't advocate/suport the "poor man's drillbit" idea of using the same type of nail with the head cut off to make a hole. There are no flutes on the smooth shank of the nail, so the abrasive scratch coat is basically being pulverized as the tip turns in the hole. This has to make a hole larger in diameter than the already narrow, thin nail. This means that you most likely will loose the "interference" fit of the nail being snug in the plaster and you will be relying on gravity and the angle of the hook/nail to support the weight of the picture. You have no way of removing material as you drill into the plaster. What if you hit a bit of aggregate and your hole is oblong?

There is a Floreat type hanger made by Frameware that we do use to hang very heavy things, but we use the hole in the center with an appropriate wall anchor that goes all the way through the lath and then we screw the hanger to it. We do not use the nails.

We use Moore hangers (the ones with a twist) almost exclusively for our installations. I prefer them because the twist holds the nail at a constant angle, the nail is larger and longer so it will pass through all layers (including the lath) and if it is in a keyway and the bond fails, it will only slip to the top of the lath instead of sliding down the wall. (I have seen this and it looks like claw marks and the picture slid down to the floor). The nail in these hangers is large enough that you can use a small carbide tipped drill bit (if you do not use a carbide bit, you will only get limited uses out of a conventional bit) to dill a hole that is the appropriate size.

We recently security installed over 700 pieces (three holes each) at the UCSD Medical center in Lath and Plaster walls - so I have a bit of first hand experience with plaster walls.

http://www.push-pin.com/prodframe1.htm
 

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I like the idea of drilling; thanks Larry.

Rob; you're scaring me, though I've not had the problems you have experienced with the Floreat hangers, and have had problems with the softer steel type hangers. Blueing is a form of oxidation, and should prevent further oxidation, and I don't believe the Moore hangers have any coating; thus would rust faster.

I did just walk over to the tool box I keep for hanging, however, and some of the old, used Floreat type nails have a rusty white accretion on them. Scraping that off leaves the blued steel, however. What rust I do see is around the head. (Those used ones are from my mothers house, on the river, and she hated AC, so the house had some real humidity issues)

The image is of a hanger I just removed from a plaster wall in my studio, in a part of the studio that has been a constant fight with the roof leaking, though nowhere near the humidity mentioned above. Notice the oxidation on the hanger. The nail, which has probably been in the wall for 20 years, seems fine except at the tip.

The hole in the wall ... is just a hole.

Another ... your mileage may vary issue. :D

P.S. It's still called lath, though metal lath is sometimes used when describing it; made of steel ... with a black coating ... hmmm?
 

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One more point on the "poor man's drill bit" technique that I left out-

If you cut the head off of the nail used with these hangers and then chuck it into a drill, there is no way you can drill a hole that is the depth that the full nail will penetrate the wall.

The problem with this is a false sense of security that you have "drilled a hole" - and then when you hammer in the full length nail, you still run the risk of blowing out a key since the nail you will be pounding in will extend past the depth of the drilled hole.

To those of you who are still believers and continue to use the Floreat type hangers - I aggree that YMMV - but my experience has been less than positive - and it only takes one picture falling off the wall to be one too many for me....

One more thought- for a 50lb Floreat type hanger you need two holes per hanger. For a 75 lb hanger, you need three holes per hanger. We never use a single hanger - so for two 75 lb hangers, you would need to drill 6 holes - each a potential for "something" to happen - and for a large installation, a significantly greater amount of time.
("something" in this case could mean some of the top coat crumbling, cracking, or with my luck, the last hole could cause a failure of the entire area resulting on relocating the hanger and starting over.)

Bron - the photo you posted is of a 30 lb hanger - and I would agree that lighter weight pictures are not as problematic. It is the heavy stuff that I feel we need to be concerned about.

The Moore hangers are plated - and I have never experienced rust problems - and we are in San Diego near the beach. Again, my biggest concern with Floreat type hangers is the scale/proportion of the nail, especially for heavier pictureas and when used with lath and plaster.
 
Rob,

I tend to use the Floreat on smaller items; if it needs the bigger hangers, I use one off of each frame upright, and I'm quick to go to other methods. I hate when frames come down off the wall, unless, not my fault, and I can charge for the restoration.:D

I also agree about using a drill bit vs a nail.

Kirstie, might I recommend an outing to the wall fastener section at Home Depot or Lowes. I recently did some installations on concrete block walls, and was amazed at the holding power of KwickTap and the other products like it. Drill, and drive a screw, that holds like a screw in wood. A lot of the products come complete, masonry bit, and driver bit for the screws themselves.
 
Don't forget about second generation plaster walls from the 1940's. The wood lath was replaced by horizontal gypsum board nailed to studs, covered with a thick layer of sand plaster, covered with a layer of finish plaster. These walls are about 1 to 1 1/2 inches thick. It works to drill through the plaster layers into the gypsum, and if it is heavy, drill into a stud. Watch out for the metal mesh that is used near corners. This can extend quite a few inches away from the corner. Very difficult to find studs in this stuff, so use outlets, switches, etc. to help you locate studs.

My neighborhood has lots of houses built during this time, with a lot of second generation plaster walls, including my own house.
 
I have been using plastic anchors and screws for hangers in plaster for some time without any problem. I have also used hangers that were screwed into anchors. It is important to have a sharp drill bit that is appropriate for masonry walls. If your bit is dull, you run the risk of the drill bit pushing against the lathe instead of drilling into it. Most of the lathe I encounter here is in the 100 year old range and very hard. This can cause the plaster to separate from the plaster keys.
 
Terry Scidmore CPF said:
These walls are about 1 to 1 1/2 inches thick.
Click to expand...

Exactly why I think the nails on a Floreat type hanger may be too short to support anything of significant weight in these types of walls as well!
 
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