how to repair plaster walls over concrete

How to Repair Plaster Over Concrete Walls

1. Remove any crumbling or damaged sections of plaster. The loose sections should be easy to remove by hand.
2. Blend a bag of plaster mix with water, according to the manufacturer's instructions. ...
3. Apply a thin layer of the mixture, around 1/4", to any holes using a trowel. ...

More items...

Full Answer

How do you fix a crack in plaster walls?

If the crack is over 1/4-inch wide, place a piece of fiberglass tape over the crack and patching plaster. Allow the patching plaster to dry. Apply a second coat of patching plaster, feathering it out along the wall. Allow the patching plaster to dry and apply a third coat if you used tape or if necessary.

Should I repair or replace my plaster walls?

If your plaster walls get cracks, dents or holes, consider repairing the plaster rather than replacing them. Repairing plaster over masonry requires fewer steps than plaster over lathe and will give you a smooth, clean surface once again. Break away any loose pieces of plaster and lightly sand the surface with a medium-grit sandpaper.

How to plaster concrete walls?

Use a wire brush to clean stains left by the mold or mortar joints. The texture of the concrete walls should be sufficiently rough so the plaster will adhere to it.

Can you use joint compound to repair plaster?

Once the plaster has dried completely, lightly sand with a fine-grit sandpaper if the plaster didn't dry completely smooth. Joint compound can also be used to repair cracks and small holes, using the same process as patching plaster. Patching plaster can be purchased pre-mixed from any home store.

What do you need to remove before plastering concrete?

How long does it take for plaster to set on concrete?

What is the purpose of plastering concrete walls?

How thick should plaster be?

How long does it take to mix plaster?

How to make dash for plaster?

See more

Will plaster stick to concrete?

Applying plaster to a concrete wall can change its appearance, level it, make it more moisture-resistant and give you the opportunity to add texture. Plastering a concrete wall takes time. You will have to prepare the wall and allow for curing and drying time between applications of plaster.

Can you repair plaster walls yourself?

If you have holes or cracks in your plaster walls or ceilings, repairing them isn't difficult. It can, however, require a bit more extra time and skill than patching a hole in drywall.

How do you repair interior plaster over masonry walls?

Procedure to Repair a Cracked Plaster Over Masonry WallStep 1: The wall is first cleaned by breaking away loose pieces of plaster. ... Step 2: The cracks observed in the plaster wall are filled properly. ... Step 3: Once dried, a second coat of patching plaster is applied all along the wall.More items...

How do you repair old plaster walls?

4:4815:23How to Patch and Plaster Walls in Your Old House - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd the patch are too dry they will absorb the moisture from your wet plaster and your plaster willMoreAnd the patch are too dry they will absorb the moisture from your wet plaster and your plaster will dry too quickly and it will crack. So we want to keep that spray bottle handy.

What's the best wall filler?

Gyproc light is probably the best all-round filler on the market. You can do deep holes with it without any issues and there is never any flashing. It's hard to ignore Toupret fillers though.

Why is my plaster wall crumbling?

Moisture is the single greatest cause of plaster crumbling in the home. You will first notice a fine white powder on the surface of the plaster that is caused when soluble salts move to the surface. Assuming the moisture issue is not dealt with the plaster is, at this point, doomed to crumble.

How do you fix crumbling plaster walls?

1:035:21Repairing a crumbling plaster wall - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd all I need to do is cut that as close as I can to the plaster you can see I'll just pull out onMoreAnd all I need to do is cut that as close as I can to the plaster you can see I'll just pull out on the wire mesh got to be careful with this might recommend using some gloves for this.

How do you repair interior concrete walls?

0:113:33How to repair holes in concrete walls and pillars | Watco - YouTubeYouTubeStart of suggested clipEnd of suggested clipWalk Oh concrete's vertical epoxy resin mortar is specially formulated to repair damaged concreteMoreWalk Oh concrete's vertical epoxy resin mortar is specially formulated to repair damaged concrete and frost damaged concrete surfaces.

How thick are old plaster walls?

A traditional 3-coat plaster is typically 7/8″ thick and when you add in the 1/4″ wood lath that supports the plaster wall, you have a wall that is more than 1″ thick! Compared to today's most common drywall thickness of only 1/2″, that is a difference worth noting.

Do I need to remove old plaster before plastering?

Whilst most plasterers are quite happy to remove old plaster or to fix new plasterboard, this will all add to the time they spend on the job and increase their final bill.

How much does it cost to repair a plaster wall?

Plaster repair can range anywhere from $10 to $100 per square foot. While this might seem pricey, keep in mind that most repairs don't even take up a square foot. Some professionals charge by the type of repair, such as $20 per crack.

Are cracks in plaster walls normal?

If your home has walls that are plastered, then straight vertical cracks typically form when the plaster expands in humidity and shrinks as it dries. These are normal and are usually the type of cracks you'll find in a new build property.

What do you do with crumbling plaster walls?

Repairing holes and crumbled plaster requires removing the damage and patching empty spaces. Scrape or brush off loose plaster to reveal the lath underneath. Drywall makes a suitable patch for the resulting bare spot, and drywall screws fasten it to the lath. Masking the repair is the same as with a drywall repair.

Can you patch plaster walls with joint compound?

Drywall compound works excellently for patching plaster walls. For best results, fill large areas of damage with a setting-type joint compound. Follow up with 2–3 coats of joint compound, sanding carefully between coats. Then, finish by skim-coating the patch with a topping compound.

How do you cover crumbling plaster walls?

4:185:21Repairing a crumbling plaster wall - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd then against molding so the next step is just to do your normal drywall mudding and tape. AndMoreAnd then against molding so the next step is just to do your normal drywall mudding and tape. And then after that I'm going to take the painters caulk and run along the baseboards.

Can you patch plaster with drywall?

0:177:53How to Repair a Hole in Plaster with Drywall - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd as you can see the plaster in the drywall are different thicknesses. And that's why it's soMoreAnd as you can see the plaster in the drywall are different thicknesses. And that's why it's so tricky to repair a plaster wall with a piece of drywall. So drywall is manufactured.

Will plaster stick to concrete?

Applying plaster to a concrete wall can change its appearance, level it, make it more moisture-resistant and give you the opportunity to add texture. Plastering a concrete wall takes time. You will have to prepare the wall and allow for curing and drying time between applications of plaster.

How do you plaster over concrete?

To prepare the surface for the Plaster of Paris you would first need to apply a scratch coat-base coat. In addition if plastering over an interior smooth surface such a concrete or cinder block wall you can also use a plaster bonder to improve adhesion of the base coat.

How do you repair interior plaster over masonry walls?

Break away any loose pieces of plaster and lightly sand the surface with a medium-grit sandpaper.

How do I fix crumbling plaster wall?

Repairing holes and crumbled plaster requires removing the damage and patching empty spaces. Scrape or brush off loose plaster to reveal the lath underneath. Drywall makes a suitable patch for the resulting bare spot, and drywall screws fasten it to the lath. Masking the repair is the same as with a drywall repair.

What is the difference between cement and plaster?

When applied to a flat surface, plaster is extremely smooth, so it’s perfect for interiors. Cement rendering involves a much higher proportion of sand for additional strength. The sand is also usually much more coarse, which helps increase the strength of the cement render.

Which cement is good for plaster?

There are three main Cement Grades from which you can choose. These are Ordinary Portland Cement ( OPC ), Portland Slag Cement ( PSC) and Portland Pozzolana Cement ( PPC) available in the market. OPC is available in two grades — 43 and 53. Both grades are considered best for plastering work.

Can you skim over concrete?

Skim coating concrete entails applying two layers of finish. The first layer is Thin Finish and it should be 1/8 inch thick. Spray the driveway with a hose so the finish will form a strong bond with the concrete. Spread the Thin Finish with a squeegee and wait for it to dry.

Estimated Time

You just gotta love plaster. That rock-hard substance, which was applied to the walls and ceilings of nearly every house in this country until the 1950s, gives us surfaces that are seamless, mold resistant, fire resistant, and noise deadening.

1. Drill Into the Plaster

Using a 3/16-inch masonry bit, drill a hole in the plaster about 2 inches from the crack. When you hit lath, stop—the bit won't go through wood—pull out the bit, and drill another hole about 3 inches from the first and about 2 inches from the crack. Try to hit a strip of lath with every hole you drill.

2. Prime and seal

Put on safety goggles and disposable gloves, then spray-pump a stream of the acrylic conditioner into each of the holes (but not into any you've marked). One or two squeezes should be enough.

3. Inject the adhesive

Place the adhesive tube's nozzle in one of the primed holes. Gently squeeze the caulking-gun trigger until the creamy glue fills the hole and a little backs out around the nozzle.

4. Clamp the wall

Slip a 2-inch plastic washer over a 1 5/8-inch drywall screw, and drive it into the lath through one of the adhesive-filled holes. The screw pulls the lath against the plaster's back side while the washer gives the screwhead a wide clamping surface.

6. Fill the crack

Mix up a small batch of setting-type joint compound and use it to fill the crack and all the holes. Smooth the wet compound with a trowel; then, as it begins to harden, wet it and smooth it again.

What do you need to remove before plastering concrete?

Before you begin to plaster your concrete walls you need to remove peeling paint and flaking bits of old plaster. Your walls should be free of paint, oil, and dust so the plaster can bond properly.

How long does it take for plaster to set on concrete?

Keep your walls moist for a minimum of seven days for the plaster to set properly. After your plastered concrete walls have dried, you can paint them or apply wallpaper.

What is the purpose of plastering concrete walls?

At some point or another a homeowner may be faced with the task of plastering concrete walls to change the appearance of the wall, make it resistant to moisture, eliminate unsightly cracking, or to add texture.

How thick should plaster be?

If you want to apply a single coat of plaster, make sure it is no thicker than 10 to 15 mm. Remember the thickness of the top coat should be 5 to 10mm.

How long does it take to mix plaster?

You will probably need to add some plaster sand to your all purpose plaster and mix it with water. Make sure you use the batch within about two hours.

How to make dash for plaster?

To help achieve this, you need to make dash by mixing one part cement to 1 1/2 parts coarse sand and add enough water so the mixture has a runny consistency. Apply a coat of the mixture to your concrete wall before plastering it and allow it to dry for a day.

Will building a wooden floor in attached garage eliminate musty odor?

Hi, I'm considering purchasing a house with an attached garage. It has a concrete floor with linoleum on top and has a musty odor I'd say is typical of garages. I haven't had an inspection yet but there doesn't appear to be leaking pipes/foundation cracking.

Trouble with installing bifold doors

I've spent over an hour and a half messing with these things, and I can't seem to get it right. Either one side is too low, the other two high, or now, they're hitting each other in the middle.

Can joint compound be used to repair cracks?

Joint compound can also be used to repair cracks and small holes, using the same process as patching plaster. Patching plaster can be purchased pre-mixed from any home store. Warnings. Check for lead in paint when working with older homes.

Is plaster wall good or bad?

Plaster walls sometimes get a bad reputation, but because they're long-lasting, durable, fire-retardant and sound dampening, they're well worth preserving. Plaster was a popular material to cover walls with prior to the 1950s and was used over lathe and masonry. If your plaster walls get cracks, dents or holes, ...

Can you repair plaster over masonry?

Repairing plaster over masonry requires fewer steps than plaster over lathe and will give you a smooth, clean surface once again.

When is finish coat applied to plaster?

The finish coat is applied after the brown coat has hardened. The integrity of a plaster surface depends on the bond between the plaster and its wood lath. When the bond breaks, the plaster cracks.

What is the brown coat on a plaster wall?

The brown coat is applied over wood lath, strips that are nailed to the studs and spaced about ¼-inch apart to create keyways for the brown coat to grip.

How to use Big Wally's?

Using Big Wally’s is a matter of drilling a series of holes through the plaster on either side of the crack, stopping when you hit the lath. Then, vacuum out the dust and squirt the conditioner, a milky liquid, into the same holes. Old plaster will suck this stuff up like a sponge.

What do you need to remove before plastering concrete?

Before you begin to plaster your concrete walls you need to remove peeling paint and flaking bits of old plaster. Your walls should be free of paint, oil, and dust so the plaster can bond properly.

How long does it take for plaster to set on concrete?

Keep your walls moist for a minimum of seven days for the plaster to set properly. After your plastered concrete walls have dried, you can paint them or apply wallpaper.

What is the purpose of plastering concrete walls?

At some point or another a homeowner may be faced with the task of plastering concrete walls to change the appearance of the wall, make it resistant to moisture, eliminate unsightly cracking, or to add texture.

How thick should plaster be?

If you want to apply a single coat of plaster, make sure it is no thicker than 10 to 15 mm. Remember the thickness of the top coat should be 5 to 10mm.

How long does it take to mix plaster?

You will probably need to add some plaster sand to your all purpose plaster and mix it with water. Make sure you use the batch within about two hours.

How to make dash for plaster?

To help achieve this, you need to make dash by mixing one part cement to 1 1/2 parts coarse sand and add enough water so the mixture has a runny consistency. Apply a coat of the mixture to your concrete wall before plastering it and allow it to dry for a day.