Plaster Wall Restoration
Summary: Plaster cracks on walls are usually the stress release points of the wall. To prevent old plaster from cracking, maintain a constant humidity in your house. To repair cracks in plaster, apply tape or large sheets of thin fiberglass mesh and spread the joint compound over this.
Related Articles: patching plaster, repair plaster, joint compounds
DEAR TIM: My daughter purchased an older home with plaster walls. There are numerous cracks in the walls and ceiling. The plaster appears to be sound. Should she skim over the existing plaster? Will the cracks reappear? Should she use the ready mix compounds that are sold in the large buckets? Is this a DIY'r project we can tackle? N. A.
DEAR N. A.: Ahhhhhhhh! Your daughter is blessed to have old plaster in relatively good shape. It is, in my opinion, the premier wall finish material. Working as a team, you and your daughter will be able to restore the walls. It will take a moderate amount of effort. Hopefully, one or both of you has good hand eye coordination.
Let's talk first about the cracks in the plaster. My guess is that in many locations wall cracks extend from the corners of doorways, windows or arches. Ceiling cracks are often random in nature. You should be able to repair many of these cracks successfully. Some, however, may continue to plague you. Here is why.
Some of the wall cracks may be stress release points. Houses tend to develop joints much like our elbows and knees. Seasonal changes in humidity can cause a house to flex at these joints as the framing lumber behind the walls and ceilings expands and contracts. The only defense when dealing with these cracks is to attempt to maintain as constant a level of humidity as possible within the house. This is often tough to accomplish.
There are several ways you can tackle the crack repair process. One method I have used with great success is to treat the cracks like new drywall seams. You tape over them using an adhesive fiberglass mesh tape or a paper tape. Successive layers of joint and topping compound disguise the repair. A final skim coat over the entire wall fills dimples, hairline cracks, and other imperfections.
Another method is to apply large sheets of thin fiberglass mesh over the entire wall or ceiling. The entire surface is then skim coated with joint compounds which hide the cracks and the mesh.
The ready mixed joint compounds may not be the best material to use. They are simply buckets of glue and filler. You can buy dry powdered setting type joint compounds that mix readily with water. These compounds contain a mixture of glue, filler, and gypsum. The presence of gypsum allows them to harden much like concrete. Same day wall repairs from start to finish are possible with these magical materials.
The ready mixed joint compounds do not always bond firmly to old plaster. In addition, they produce a somewhat softer final surface which may scratch or ding more easily. The setting type joint compounds can be mixed with water and acrylic bonding liquids. This permits them to readily stick to the old plaster.
If you want to avoid dust storms during the final stages of your project, why not buff the walls with a rubber float? These tools are used to grout ceramic tile. If you slightly dampen the dried joint compound and glide the float over the wall surface, you can create a smooth finish that rivals that of the original master who installed the plaster.
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Comments:
amy spina 12 Dec 2007, 21:48
Hi Tim--
I have a question about this wall we're trying to something about. It's a kitchen wall that is very uneven with layers of plaster coming off, and layers of concrete filled in certain areas. It seems to be made up of partly concrete and partly old plaster, which is covering brick, and no wood joists. We would like to fill the large spaces where the plaster has fallen off and left 1/2" to 1/4" depths and where the concrete has eroded into holes and we're wondering what would be best to fill these gaps and areas of plaster and part concrete. After we get the wall fairly flat, we'd then like to cover the whole thing with a 1/4" layer of drywall just to give it some smoothness and consistency---but we will be screwing into brick. So, we'd also like to know what we would have to use to get the wallboard up..... or maybe there's another approach we need to take??---I hope you'll be able to point us in a good direction. Thank you for any advice you get give us.
AsktheBuilder 15 Dec 2007, 10:06
Amy,
Please read all of my Plaster Repair columns. I mention a product called Structolite. That is what you need along with some Durabond 90 and a grout sponge.
john 18 Dec 2007, 00:58
I've been repairing and painting old plaster walls in my apartment. I also
used fiberglass tape and a skim coat of joint compound over the entire wall
to get them really smooth, I just figured out the hard way that you have to
use a very short nap(1/8")quality roller or the paint will get an orange
peel effect, the difference is amazing!
Michele Rosen 27 Dec 2007, 16:27
Dear Sir,
I have several areas on an exteror wall of my 50 year old plaster wall that have lots of cracks when I take a putty knife to the area the entire top surface lifts off leaving a white colored layer that is not smooth. I have knocked of the top layer. Can I fillthis area with bondo for adhesion. The ares is approximately six feet long eighteen inches high. I tried using Hard Rock Water putty cracks all reappeared. A plasterer used something called California coat cracks all reappeared. I am unable to redo the entire wall do to architectural mouldings on much of the wall.Please advise. Thank you, Michele Rosen
AsktheBuilder 27 Dec 2007, 16:36
Michele,
You need the dry-setting compound like USG's Durabond 45.
Kevin 31 Dec 2007, 19:34
Hi, I hired a plasterer to repair and do my walls. He first applied
structolite pure with water and filled the holes. I noticed within 5 hours
the product cracked and he said it was normal. 2 days later I noticed it
had dried and cured, but the structolite is very dense and hard in some
areas, some areas it feels like it never adhered to the original mud/ lathe
base, and some areas its brittle and fell off. What to do?
AsktheBuilder 31 Dec 2007, 19:39
Kevin,
How about buying a copy of the Gypsum Construction Handbook? That is the bible of drywall and plaster installation. The link to it is just above the first comment and just under the column. Without seeing the job, it sounds to me that the plasterer might not have removed all of the loose material and/or applied the product over unsound lath.
steve taylor 03 Jan 2008, 09:42
i have a old house biult by slaves. the plater is cracking and has a white
foam looking serface in places. the paint is pilling off. what do i need to
do.
AsktheBuilder 03 Jan 2008, 19:05
Steve,
I think you need to follow the advice in all of my plaster repair and painting columns. Get some bean juice brewing and get ready to discover some tips that will rock your world.
Joe 16 Jan 2008, 20:03
We are remodeling this very old home. We,my partner and me, as to what to
do first. We are adding a new bathroom, need to paint walls/wallpaper, add
a new flooring, which needs new plumbing for toilet and sink, and subfloor.
We are trying to do most of the work ourselves to cut done the cost of
this project. Can you please tell us what needs to be done and in what
order to do them. New floor over old before plumbing? Paint/wallpaper
walls before subfloor? Subfloor then plumbing? We need help. Thank you.
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