How to Repair Cracks in Plaster Walls | Ask This Old House

In this video, Ask This Old House painting expert Mauro Henrique shows Kevin O’Connor how to handle cracks in plaster and drywall.
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Mauro Henrique gives Kevin O’Connor a lesson on patching cracks in plaster and drywall. After explaining to Kevin that his paint job is only as good as the prep work, the two discuss where cracks are most likely to occur before diving into a few repairs.
Time: 4 hours
Cost: Under $30
Skill: ⅖
Materials:
Fiberglass mesh drywall tape [bit.ly/3q8EjB7]
Joint compound [amzn.to/3zMZ88t]
Flexible patching compound [amzn.to/3Ge6Evn]
Tack cloth [amzn.to/3Gijqck]
Tools:
Utility knife [amzn.to/3GlduPY]
Putty knife [amzn.to/3FkCqWp]
Sandpaper [amzn.to/3FjzXvx]
Steps for repairing plaster walls
1. Start the project by cleaning up the crack with the utility knife. Look for compound, paint flakes, and other debris in the crack and scrape it out.
2. Using the putty knife, apply a thin coat of joint compound to the crack. Start at the top of the crack and drag the compound down, pushing it into the crack as you go. Remove the excess compound by pulling the blade of the knife across the crack at an angle (not perpendicular to the crack).
3. Apply mesh tape over the fresh compound. Starting at the top, lightly press the mesh tape into the bed of compound before using the putty knife to cut it at the bottom.
4. Immediately apply a second coat of compound over the top of the mesh tape. Starting at the top of the tape, apply the compound and remove the excess. Wait 45 minutes to an hour so it can dry.
5. Lightly sand the repair area to remove any high spots and ridges while also feathering the edges of the repair. Use the tack cloth to remove the dust. If the repair or crack is still visible, apply a third coat and feather the edges with sandpaper once dry.
Patching Cracked Plaster: Small cracks
You can handle some small cracks with a two-coat process using a flexible patching compound, and there isn’t any sanding required.
1. Ensure that the crack is free of debris by scraping the putty knife over the crack.
2. Apply the flexible patching compound to the crack. Start at the top and work your way down, pushing the compound into the crack.
3. It’s important to remove the excess patching compound as it’s not sandable. Drag the blade of the putty knife across the crack at an angle (again, not perpendicular). Ensure that there aren’t any high spots or mounds left behind before allowing the compound to dry for at least two hours.
4. Once dry, apply a second coat of the flexible patching compound in the same manner as the first coat. Again, be sure that there aren’t any high spots or ridges left behind. Allow this coat to dry before painting.
Where to find it?
Mauro shares the best techniques for patching and repairing cracks in plaster walls. His go-to material is a flexible patch compound, Sheetrock® Brand [www.usg.com/content/usgcom/en...] Dust Control Patch and Repair Compound [amzn.to/3Ge6Evn], specifically used for stress cracks on the wall. Mauro also used fiberglass drywall tape 2”x 150’ (50mm x 45.72m) by Dynamic [bit.ly/3q8EjB7]
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How to Repair Cracks in Plaster Walls | Ask This Old House
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[@lamesjewis6618]

I've been watching This old house since it was child, we didn't have cable and PBS was always the go to for my parents, I'm now 20 years old and living on my own. I want to buy a house soon and one of my biggest obstacles was my personal lack of knowledge about maintenance and repair of common household items. These guys give have always shown me how I can fix things on my own and they have given me hope for myself and I'll be sure to look to them whenever I need to fix or improve something. Its also good to see a familiar face from my past.

[@michaelmcgee2026]

I'm self employed doing remodeling and I've picked up a lot of things from these guys

[@shisharupu]

I just bought a house and I'm going through the same exact thing. All those years of watching PBS are coming back 😆

[@biggering]

You got the sequence of events mixed up there. Buy the house first, THEN you’ll learn about maintenance and repair pretty quick! I’ve also been watching TOH since forever, I think since I was a kid in the 80’s. It’s just as good now as it was then.

[@jimmay1988]

Smart move. I just bought 2nd home and regret ignoring this show on local channels.

[@christophercastor6666]

Plaster!! Finally!!!! I have a Craftsman style home from 1913 that’s grown several times over the years. It’s a combination of plaster and drywall with many generations of “patches” in different areas. Thank goodness for your advice and please pray for my success! 😂 Thank you as always! -CY Castor

[@randomrazr]

did it work

[@mikesalas2683]

Thank you for the tips and steps repairing plaster walls and painting I will do this week a bedroom thx again Mauro

[@juvalue_]

Thanks I plan to get this done this weekend!

[@kingart813]

Love love love this! Thx for the reasons and showing the final product

[@srharris88]

As a painting contractor for 18 years, i don't agree that air drying joint compound with mesh tape is ideal. Mesh tape is designed to be used with quick setting joint compounds AKA hot mud. Also for an area that has cracked and been moving, paper tape is much better. In this situation Id recommend using standard air setting joint compound with a paper tape, your repair will last longer.

[@JonnyDIY]

"Looks good from my house" 🤣

[@salvadorsepulveda6415]

The best job by the best craftsman !

[@drewdoestrucks]

A professional once told me to grind cracks like the first one when using joint compound. Just wondered what y’all thoughts were on that.

[@codymayrer5059]

This Old House, would you be able to do a video on matching common types of texturing on drywall. I can do patches where they are smooth but not sure on how to match.

[@danb.709]

Almost always it will need retextured as well, they didn't mention that and it's probably the trickiest part of the job. A perfectly flat area sticks out like a sore thumb on most walls.

[@scottslotterbeck3796]

That's kind of obvious, don't you think?

[@mikebeverly88]

No all plans have textured walls its not common in my area.

[@stacyshaw1871]

I’ve seen textured wall spray at Lowe’s, could be worth checking out

[@scottslotterbeck3796]

@@stacyshaw1871 I retextured my whole house after I bought it. The former owners went crazy with wood paneling and wallpaper. The best solution is to buy a texture gun. Wagner makes one. The best ones are air powered. They do an excellent job.

[@danb.709]

@@stacyshaw1871 Those work really well for small jobs or touch up, however it's very difficult to get consistent results throughout a whole room. Also they aren't cheap, and some of them absolutely stink of solvents. It's a good idea to prime both before and after. Always do a test area on some cardboard to make sure the can is working as expected and the results can be excellent. As someone else said, on any large job or area, an air compressor powered sprayer is the only way to go. They run about a hundred bucks and getting the mix just the right consistency takes some trial and error, but if you're doing whole rooms it's a necessity.

[@trevland1303]

Nice 👍

[@DalePoole]

I'd like to see some videos about repairing those 'hit and misses' from former home renovators. I have two big seams in the walls of my dining room, left by a seam patching that was too thick. It looks like speed bumps on the walls. I'd like to know how to repair this without ruining the walls.

[@Guardducks]

Here is a video that may help with your dilemma. kzbin.info/www/bejne/eajNiIKeqJJ2rsU

[@seeya205]

You can sand them level or you can feather them out more with more mud. Sand, prime then paint.

[@steffen1557]

When using mesh tape, I never use regular joint compound with it because of the shrinking of the regular compound. I've always used fast setting type.

[@CherryClayton]

Agreed..also fiber fuse tape is much better too

[@unlazyfree]

@@CherryClayton I love the fiber fuse tape as a finished product over anything else, but I hate working with it more than anything else because no matter how careful I am, I always get f'ing fiberglass in my skin.

[@stich1960]

Yeah this was bad, usually TOH is on point, kind of sad to see them giving out bad info here

[@ryane6719]

It’s literally on the instructions, must use setting compound for first coat minimum. You’re right, and this video is severely lacking.

[@juliemarchese-temple7749]

HOW DID TOH MAKE THIS MISTAKE? ISN'T KEVIN AN EXPERT AS WELL?

[@redivider6430]

Glad to see Omar Navarro from Ozark has a side hustle.

[@Rocky-xx2zg]

From my experience with wall/ceiling cracks , someting is moving. I try ro fasten dryall screw on eith side of the cracks into the joists or studs. Then apply the patching material/tape. JMO

[@womblestacker7993]

Take it every time

[@xoxo2008oxox]

The link for the flexible patching compound is incorrect. It should be to a product like demonstrated, the DAP ElastoPatch (the container is turned away from camera likely due to licensing, advertising, etc). An elastomeric spackling compound is ideal for small, thin cracks and no sanding, with benefit of expansion and no further cracking. Latex paint works well.

[@annacortez7200]

Thank you!

[@jamesvelasquez1342]

What about fixing external Cracks for different types of materials ?

[@LarryDavidshow]

I've been doing drywall for 35 yrs not saying he is wrong but 5 or 20 min is a better solution and you don't have to fill the crack first, it doesn't matter that's what mesh tape is for. But everyone has their own technique

[@Czechbound]

No primer on the new repair before painting ?

[@cbylsma626]

You guys should do a video on Plaster Magic, my wife researched and researched for the best way to repair century old plaster and discovered that Plaster Magic is THE product to use, he has some videos available that explains what it does and how it works and why he marketed it. The person who produces the product does restoration specializing in significantly important historical buildings.

[@ryane6719]

Wallys is for sure the best.

[@sylc6688]

A "pro" fixed my plaster wall cracks using meshtape and hot mud, then skim coat the walls, cracks were back 2 months later and tape is bubbling out.

[@vitaliylapatin]

Mauro the great paint

[@AWAKENDUSK]

Should prime before painting !

[@bernardfitzgerald5697]

Everytime I sand it seems to expose the mesh tape. If I sand less to not expose it you can see the bump where the tape is, even if I go wide with the spackled area. Any advice?

[@malexander453]

This is great info but what about heavily textured plaster walls?

[@croboy751]

Same way. Just let the patch dry like he did and scrap all the boogers or sand. Then add a thicker coat of joint compound to match the existing texture and use what would match the patch. Usually a shoe brush, plaster trowel(for skip-trowel texture), sponge, or a crows-foot brush usually are the main texture. Pop-corn texture is sprayed on and usually sell a small repair kit for it that uses an air compressor

[@christa7174]

What about cracks in plaster where there isnt a space to fill? The dent of the crack is outside

[@don361]

The link above does not go to a flexible patch material.

[@ronevans852]

Wow, when I try to do that at my house doesn’t work like that. Good job.

[@zachmiller4930]

It doesn’t work like that for anyone. That’s a completely wrong way to do the job and they only made it look decent on camera.

[@HAMRADIOJOE4178]

YEP FLUFFERNUTTER LOL

[@rich52movie]

When sanding your work, lightly run fingertips over the sanded work, if sanded correctly, it should feel completely smooth without any bumps or crevasses. If imperfections are felt, more sanding is needed. When satisfied, then paint. Good luck.

[@cmeller55]

How can you not sand the flexible compound? What if it drys uneven?

[@scottslotterbeck3796]

You have to be careful in applying it. You can also put a very thin second coat where needed.

[@unclebuild8480]

Make sure it isn't uneven.

[@richdowd5728]

Christoper Meller: Some flex compounds are indeed sandable. The one I use isn't. Here are my tips. Strike off all of the compound when you apply it so that it's all in the crack and none (or just a haze) on the surrounding area. The compound shouldn't run the full width of your knife when you're applying it. What they didn't mention here is that the elastomeric (flex) shrinks, even though the package says it doesn't. At least that's been my experience. So I do a first pass with the flex, top-coat that with joint compound (after it dries), and then sand the joint compound. That gives me more control in feathering out the edges. I hope that helps.

[@rhodachandler4277]

Shouldn't you spray some water on the plaster crack before you fill?

[@pecv4776]

What kind of stuff they are using it they should show on the video

[@ryane6719]

They have no clue what they’re doing from a technical standpoint

[@paigeharmon6354]

To match texture, wad up a plastic grocery bags and dab the area. Keep dabbing lightly until you get the right texture.

[@unlazyfree]

Right side of the left crack wasn't sanded/blended enough. You shouldn't see a solid line between your compound and old paint. Pet peeve of mine because I'm now fixing my own prior drywall mistakes that I just couldn't stand looking at anymore. Also, I tried and prefer the randomly placed fiberglass tape over mesh or paper (unless it's a corner). Blends far better and I haven't had a single crack reappear (unlike some of my earlier repairs using mesh or paper)

[@karlhungusjr1]

no one cares about your opinion.

[@ian22222]

Good on you for going back and fixing your mistakes!

[@kdknitro]

did you see the low spots, man this segment was a joke.... i sure he can do better in real life. Gotta love that TV magic how its so "perfect"

[@syntecsmurf]

@@karlhungusjr1 No one cares about yours. We all know what kind of people do not like free speech.

[@rickfromthecape3135]

@@karlhungusjr1 Actually his opinion is better than this video. So you should care.

[@johnnichols2710]

Never use joint compound with mesh tape. If using mesh tape use quickset or plaster like durobond.

[@merkitty6613]

"may I?" As his hand is already touching the spot, why bother asking permission then? Lmfao

[@RixceU]

This is not the best way. I suggest watching a drywaller channel, such as Vancouver Carpenter, for better methods to repair drywall. Mix your joint compound in a mud pan first, it will apply much smoother. Like others said, use fast setting type like Easy Sand 20 or 45 for the first coat with mesh tape, then all purpose for second coat. It doesn’t matter you you put on joint compound; it matters how you take it off. In other words don’t apply it little by little; apply a lot and then smooth it down in long, continuous motions. Feather the edges of the mud you apply by pressing harder on one dude of the knife as you smooth the mud. Use a wider knife (10, 12 inch) on the second coat. Because of the tape, the repaired area by nature has to be higher than the surrounding wall. You need to extend the mud by a wide margin and feather it so the change in height is not noticeable. If done properly, very little sanding is needed.

[@donc-m4900]

looks like drywall, not plaster.

[@ryane6719]

This video is full of error, sad because people will surely be misled.

[@womblestacker7993]

Tape ot all doesn't re crack even for smaller cracks they always cone bk

[@viviolagabriela07]

I like Mario 😍

[@Pure_KodiakWILD_Power]

Kevin's cracking up at his joke, thinking: _.oO( fluffer nutter, I got off a good one..._

[@davidpearson3304]

Not really he messed it up…, fluffer nutter is the sandwich made with marshmallow fluff and peanut butter. Any real New Englander knows that. 😉

[@donc-m4900]

He should have stopped at Fluff.

[@S4RWS]

Mauro didn't understand what a fluffernutter was...

[@juliemarchese-temple7749]

WHAT A JOKE! GOOD CATCH ALL YA NEW ENGLANDAS!

[@theshoptopauto]

Grab a damp sponge to " sand" smaller areas . Dustless and as affective as sand paper lol

[@patzeuner8385]

Tried the damp sponge technique to smooth out seams and patches a couple of years ago. Haven't had to deal with dust from sanding ever since. Also since you use the sponge when the compound is still a bit damp to smooth the surface, once the surface is dry you can seal and paint. Cuts down on a lot of time.

[@theshoptopauto]

@@patzeuner8385 Agree 👍

[@ryane6719]

Why are they using the term plaster and drywall interchangeably? Second, you CANNOT use mesh tape with ready mix compound.

[@andrewschafer8986]

Agreed, very surprised about this coming from this old house...

[@juliemarchese-temple7749]

ARE YOU SAYING THAT WAS INCORRECT??????

[@andrewschafer8986]

@@juliemarchese-temple7749 yes there is a difference between the two

[@randomrazr]

why canrt u use mesh tape with pre mixed mud?

[@ryane6719]

@@randomrazr ready mix will crack, it’s strength yield is much lower than hot mud.

[@walkerstriplingremodelingr2751]

This is the biggest horse load dung video This Old House ever made

[@user-ov1hw5wm2g]

Don’t care how little joint compound or spackle you use should wait at least 12-24 hours to paint.

[@iceman846]

Plaster Paris is best

[@Dirtyharry70585]

Well left hand at the top was soso

[@codyo4867]

What type of finsher even is he, it looks like a home owner put it on!! Where do they get these people!

[@headrush3161]

Highly disappointed he didn't prime before he painted.

[@ImTheJoker4u]

Great except I have textured plaster walls🙄

[@ryandiedrich6317]

They make texture in a spray can you can use. Works pretty good!

[@5410th]

Gotya, Gotya. I am sick of hearing it, Kevin!

[@leoharskamp5930]

before he started a drip of paint just before the piece (6:03), he painted all over the tape (6:06) (really, is he a pro?), cherry on the pie left top he painted the trim as well (6:14)

[@MrVinceChannel]

He is demonstrating what usually happens. You pay someone to fix a problem and they'll always messed something up.

[@cagaleched3459]

Get a life dude!!!!

[@johnmolnar2957]

Glad you aren't working in my house, really that's amateur work!

[@heithblack4828]

If you know you know.

[@rickfromthecape3135]

Yep.

[@danielrussell9416]

Mesh tape requires hot mud.

[@smarthome2660]

No information is better than the wrong information. This video should be sent in for professional review as all of it is just wrong. Not feathered out enough, not sanded enough and only one coat of paint on a fresh repair is not professional.

[@ryane6719]

Those aren’t even the real issues. The real problems arise from them not even being able to disseminate what substrate they have. Plaster and drywall are vastly different substrates and require different means to both mechanically affix and to finish. I 100% agree the video should be pulled or edited heavily.

[@Darkseid001]

The ginger 🤣

[@karlhungusjr1]

"yes Kevin *sigh*.................."

[@jimmyobando938]

All crack has to be fixed with durabon no compound

[@marymack4105]

These are cracks in drywall not plaster. Two different things.

[@GalacticTradingPost]

modern plaster is plastered over special drywall.

[@tickytacky8078]

When are you going to do a video about horsehair and lathe fixes? I fixed countless cracks after my father passed and I watched him fix countless when I was a youngster! They're horrible! Edit: 1773 colonial

[@georgebush6002]

Based on the title that was what I was expecting :)

[@MandoFettOG]

They already have

[@TjaVideos]

way too much repair on the left crack, just a thin extra layer is enough.

[@ericaulbach]

Plasterer here. SMH.

[@rockobukkako813]

These simulated cracks are unrealistic when it comes to plaster

[@scottslotterbeck3796]

I have fixed many, many plaster cracks using the elastic compound. Works well. Perfection is only in heaven.

[@headrush3161]

​@@scottslotterbeck3796what does heaven have to do with this?

[@dudethedude50]

I would fire this guy ASAP if he used joint compound on plaster. He's a painter, so why ask him how to fix plaster? This old house used to be about how trade does things. Now you have an ex banker showing what I think you really shouldn't do. Fail. Badly.

[@mwoods5166]

This guy cant be doing this for a living. That first coat he did was horrible and ge left it on way to heavy especially on the edges. That would take malot of sanding plus extra work to fix that first skim. They never mentioned he added a second coat of mud on the bigger patch. You dont sand with hand paper like that either you put it in a block or use a sponge block.

[@chadk9532]

Paper all the way. Sorry I have to disagree this time.

[@scottslotterbeck3796]

Paper sucks. It has no flexibility. Mesh only.

[@chadk9532]

@@scottslotterbeck3796 Evidently your not a finisher!

[@scottslotterbeck3796]

@@chadk9532 LOL. I've been a professional handyman for 40 years. I have forgotten more than you'll ever know.

[@ryanwilson5936]

@@scottslotterbeck3796 So, you over charge people for half-assed work? That’s what “professional handyman” means in my experience. I’d rather learn something and have new tools at the end of my project than pay for someone else’s ego. The last “professional handyman” I encountered told me that it was impossible to replace my already grounded 2-prong outlets to 3-prong because there wasn’t a grounding wire and it would cost thousands to re-wire everything. Needless to say he left unpaid and 30 minutes, $14, and some KZbin videos later I replaced most of my 2-prongs to fully grounded 3-prongs myself. You remind me of that guy.

[@scottslotterbeck3796]

@@ryanwilson5936 I couldn't care less what you think.

[@KefirTView]

NOT a good video by any means. I quickly noticed two huge mistakes being performed that any painter or person with patching experience should have known immediately. Both repairs will fail within 1 year of completion.

[@Yorkie285]

Looks like crap

[@rickfromthecape3135]

Yep. As usual.

[@matthewbusch7963]

It is garbage. Never use mesh tape with premixed mud.

[@rickfromthecape3135]

They rely on the fact that the camera doesn't pick up the imperfections in the mud. You can clearly see one at the top of the patch.

[@scottslotterbeck3796]

Everyone's a critic. This is a demonstration, not reality Get your own f---ing show. LOL.

[@billyp2465]

@@scottslotterbeck3796 You don't need to have your own show to know what craftsmanship is, buddy. Anyone who works with drywall or plaster knows, you can't hide a taped joint with a 6" knife. It wasn't even a good demonstration.

[@Danthemanfromny]

Bad, tackle a real job. Thrown plaster, hundred year old cracks botched by previous caretakers. Cracks in plaster seldom run in straight vertical lines.

[@patrickcullen2714]

i hate to say it but its amateur hour on this episode

[@ericworthington5615]

This is to fix drywall not plaster. Useless.

[@dks13827]

Great woke video. Habla.

[@YAWN....]

Amateur