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Plaster repair in non-visual locations

I had to remove the capital on an interior door because it had come loose. The plaster behind the capital is cracked and a few small pieces are missing. The house was built in 1915. My question is, should I repair the plaster behind the capital or should I just rehang the capital without the repair?

Re: Plaster repair in non-visual locations

Personally I would just patch it with spackle and caulk and reinstall the capital.
Unless the plaster is really loose and ready to fall off.

Re: Plaster repair in non-visual locations

You can get dry plaster mix at Lowes/HD and mix up as much as you need. It has a very short working time (10-12 min), but other than that its very much like working with spackling compound. I have also used some small pieces of fiberglass drywall tape to bridge between two pieces of plaster or stuck in a wide crack to give the new plaster patch something to stick to.

Whenever I am working and accidentally crack or break plaster I prefer to stabilize it as much as possible and get it back to the original state. I think plaster is great, but its also very stiff and once a break gets started it seems to "run" quickly if conditions are right. Small cracks often turn into larger cracks if they are not stabilized.


Re: Plaster repair in non-visual locations

Prep the broken edges and exposed lath with bonding agent, and fill the voids with basecoat plaster like structolite.
Patching plaster from the big box store is pure gypsum (plaster of paris) and has a host of shortcomings that recommend against it. Brittle; won't bond to old plaster; no working time. The original white coat plaster in old houses is primarily lime with a small portion of PoP added as a hardener. That's why lime plaster has a longer working open time and bonds to the basecoat.
The best thing for a homeowner to fix small cracks with is Durabond 45, a setting-type drywall compound that is mixed from a powder; it sets and dries faster than ordinary mud, but the "45" means it has at least 45 minutes of open time at normal temperatures. It has additives (a glue) which help it bond better to all substrates, is moisture-resistant when cured, (great around showers and tubs). It cures very hard and is not sandable, but it can be scra=ped off to level as needed, and top-coated with the sandable type (Easysand ) or ordinary green-lid wallboard compound for a durable repair. If you want to go deluxe, use bonding agent and fiberglass mesh tape on the cracks and the results are even longer-lasting, unless the cracks are still moving.

Re: Plaster repair in non-visual locations

I try to caulk, patch or spray foam anything and everything as I have the world's draftiest house.

Keeps bugs out, too.

Re: Plaster repair in non-visual locations
Sombreuil_mongrel wrote:

It cures very hard and is not sandable, but it can be scra=ped off to level as needed, and top-coated

The setting compounds can be sanded level but it takes about ten times the effort. I use them quite a lot on repairs, preferring the 20 min type when I can get it (it's often sold out at my suppliers) but with that, you've really got to work fast. Like most of these, the time rating is optimistic, I find that you get about 2/3 of what they claim before you better start cleaning it up unless you like cleaning up with a cold chisel and a hammer :eek: If it seems to be getting stiffer, clean up immediately and make a new batch.


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