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I'll admit, I'm definitely a novice when it comes to finishing drywall. I've done loads of patching, which doesn't typically require working with corners. This time, however, I'm doing a whole room.

I watched some YouTube videos, and read a few articles online about how to properly finish inside corners. Everybody makes it look so simple, but I just can't seem to get the hang of it.

The process goes something like this...

  1. Put some drywall compound on each side of the corner.
  2. Fold the paper tape in half.
  3. Press the tape into the mud.
  4. Place a corner trowel in the corner, and with gentle pressure on the back of the trowel draw it down (or up) the corner.

The first problem I was running into, was that instead of the trowel sliding along the tape. The tape was being pushed along by the trowel, and it would bunch up and be removed from the corner. I solved this by pressing a bit more gently, and holding the tape in place just to get started.

The next problem I ran into, was that while I slide the trowel down the corner, the tape would ripple and bunch up ahead of the trowel. To fix this, I had to use my taping knife to smooth the wrinkles out of the tape. While this worked in the long run, it seems less than ideal. This extra step was never mentioned in any of the videos or articles, which made me wonder what I was doing wrong.

Am I adding too much (or not enough) compound to the corner? Applying too much pressure with the trowel? Or do I just need to work on my technique?

  • I'm interested what a more professional opinion is on this. I too am preparing to mud a whole room for the first time, but I've only ever used the fiberglass mesh instead of true paper tape. Maybe it's related to the tackiness/lack thereof of your compound? – BrownRedHawk Mar 2 '15 at 15:35
  • @BrownRedHawk - I would never use mesh for corners. I use paper for inside corners, mesh for flat transitions and holes, and metal outside corners that are stapled. – DMoore Mar 2 '15 at 18:16
  • We're not arguing the type of tape here, that's for another time. – Tester101 Mar 2 '15 at 18:24
  • I've not had the issues you are talking about with a corner trowel. It just seems to work for me ... guess I'm special that way ;-) It might also have something to do with the angle at which you are pressing the corner trowel into the tape ... – Pᴀᴜʟsᴛᴇʀ2 Mar 3 '15 at 2:12
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    FWIW, I don't mud inside corners. I get a nice tight butt joint, then a nice thick bead of caulk. Knock-on-wood I have yet to ever have an issue with these corners. – DA01 Mar 3 '15 at 2:52

11 Answers 11

5

I would say you have too much compound. You should be able to press very firmly and pretty much squeeze out the excess compound. The thin layer that remains will provide good adherence of the tape. You want the compound to fully coat the back of the tape, but no more.

5

I have watched my drywall guys and have a much lengthier adaptation to what they do.

Note: Your drywall mud should have the consistency of a very oily peanut butter. The premixed stuff in buckets at big box is too thick. Add a little water and a couple of drops of Dawn to it. If it is too dry you may find more air pockets and your tape not binding well with wall. If too wet your tape will tear when trying to squeeze of the mud.

  1. They don't use a corner knife and either do I. I find that I end up moving the paper or ripping it.

  2. To apply the layer of mud before the tape I either use a 2" knife vertically or a much larger knife in horizontal swipes. And this next tip is definitely stolen and the key - scrape off the excess mud with a 10-16" knife. The putty knife is flat against the wall so this should make you scrape until your corners are 90 degrees. Most/all corners dip in due to screwing. Also if you do this just right you will leave a very thin strip of excess mud down the middle which is fine. The goal is that your mud should be 2-3 inches out of corner all the way down both sides.

  3. Fold tape in half and start from top. Press corner tape firmly into corner but do not push hard. Go all the way down just using your finger. Cut tape to size.

  4. With larger knife (10" and up) start at top. Put knife in corner and lightly press out horizontal on tape with a horizontal/down motion (obviously the very top is more horizontal). Do a couple swipe on one side of the corner tape and then do the other side and work your way down.

  5. Excess mud should come out during step 4. If there is a ton then step 2 was done incorrectly. If too much mud your tape may get to wet and rip. If you find yourself in this situation it is much easier to remove tape and start with step 2.

  6. To remove the small excess mud take a 6" knife (or bigger if you are more skilled) and start at the top corner on one side and swipe from top to bottom. I have seen my pros do this in one swipe. You will have more pressure on the knife towards the corner but not so much that you tear or move tape. The excess mud is good/fine and it should be thicker right now so the tape binds to wall well.

  7. Given you aren't just doing inside corners (and always try to do inside corners first) go back to this corner about 30 mins laters, maybe an hour. It should be kind of dry - if it still looks sopping wet don't touch it. Put your first coat of mud over the tape on one side of the corner. Use a 4"-6" knife. The key to this coat is that it should be flat. Instinct is that you would have more mud in your corner and smooth down to flat wall. No. Your corner should not be built up and you shouldn't be worried about smoothing to drywall until at least the next coat.

...and this is where I really diverge from my pros.

  1. I wait 1-2 days depending on type of mud and room conditions. I want everything 90% dry. If I put the first coat of the other side of the corner on I would certainly mess up the opposite side. My pros do these at the same time, hardly ever mark the other side and when they do they don't spend 20 mins trying to fix it like I do. Again this is a 4-6" knife done flat. So to recap we put our tape down and first outer coat on just one side in day one and day 2-3 we will do the other side.

  2. Again differing from my pros. Here my pros would bust out a 12-16" knife put a crapload of mud in the corner and it would look perfectly feathered in 2-3 mins a corner. Also it would take very little sanding after. I have no ability to do this so I bust out an 8-10" knife and put my second top coat on.

  3. Scrape any bumps or ridges with 6 inch putty knife after step 8-9 dries. Probably a day later unless using quick set.

  4. Put down finish coat with 12-16" knife.

  5. Scrape any bumps or ridges with same knife a day later, sand with 120 grit. Finish sand with 240+ grit.

  6. Tell yourself that because it took longer it is better [Even though I see far more pinholes in my finish than my pros - they are obviously cheating]. Actually the pros method that I have seen actually does take as long technically because their top coat is so heavy they often have to wait 3 days to sand it. Now they would say but we only had to work on it twice vs. my 4-5 times but that is semantics. Both done on the same day.

  • So... You're saying my mud was too thick? – Tester101 Mar 2 '15 at 18:48
  • I think so. Thick mud will make you knife stick. I am not sure about the usually issues with corner knives since I ditched them 15 years ago but when my kids are doing work for me they forget to add water and then when you push against tape it tears instead of pushing the mud out. – DMoore Mar 2 '15 at 18:52
  • The mud is pushing out, and the tape is not ripping. Instead it seems like the mud is too slippery, and the tape is sliding around too much. – Tester101 Mar 2 '15 at 20:05
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    If it is sliding without ripping that is a pretty good sign that your mud consistency is OK. I would say you have a little too much mud under and not enough outside. Also instead of swiping down/vertically which if I do this I end up with same problems half the time - swipe with a bigger knife horizontally while starting in the dead corner that is already pushed in. Problem with pushing down is if you had to much mud it will eventually not push out and will build up to cause tape to slide or rip. Yours is sliding so most of what you are doing is right on. – DMoore Mar 2 '15 at 20:12
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    The reason why corner trowels are not used is because most corners aren't shaped for the trowel. Maybe you are doing nothing wrong but wrong tool. – DMoore Mar 2 '15 at 21:31
2

Taping is a skill. I'd say, with my learning curve, it's 30% knowledge and 70% skill. That being said aside from the consistency of the mud, the things that I've found for inside corners are:

  1. Make sure that the mud is evenly applied on both walls(uniform thickness on both walls and smooth) and has no bubbles. It's easier to under apply mud than over apply it. Apply the mud with a 4-6 inch knife, and smooth it with your corner trowel.

  2. When putting the tape in the corner, put some tension on the tape. This may be what you're doing wrong. Press the tape in gently with a 4-6 inch knife.

  3. For the first two feet or so, hold the tape in place at the top as you work the corner trowel downward.

2

Don't use a corner trowel to set the tape - the extra surface contact, and the pressure required, drags it out and through the joint. A corner trowel cannot be used effectively, as the sole tool in a corner - period. They are typically, only 4" wide, from corner to edge, and are intended for the finish stroke, that defines the corner - not the stroke that sets the tape in the mud.

Only use the corner trowel to level out your "bed" for the tape, and the finish stroke, to define your corner.

You must still use a flat knife (normally a 6") to put the mud on the wall, set the tape, and feather the ridge left by the corner trowel. An additional step, would be to follow up the next day, with an 8", to blend (skim) it further into the wall.


If you want to spend a lot of time, teaching yourself, the precise amount of mud, and the precise amount of pressure, needed to accomplish your goal - without a flat knife - more power to ya - but that's what it will be, a lot of time. Drywall finesse, is really difficult to explain/teach, in a text environment, and even YouTube videos fall short. The brand/type of tools used, consistency and type of mud used, and even the temperature and humidity, of the room being finished - all tug and pull, at what makes sense, in your hands today, but might not be the case tomorrow.

  • I've seen tons of videos where folks use the corner trowel to bed the tape, which leads me to believe that it can be (and is) done. I've watched videos of both techniques (corner trowel vs. flat knife), and in all cases the corner trowel was faster. This question is not here to debate which tools/techniques are better, it's to figure out what I might be doing wrong with this technique. – Tester101 Mar 3 '15 at 11:49
  • Please link to said videos... – tahwos Mar 3 '15 at 12:47
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    This. Perhaps your question should be How to use a corner trowel to set tape? or you will be forever hounded with, don't. @Tester101 – Mazura Mar 3 '15 at 20:00
  • I agree with tahwos. After trail and error and error i found just the right amount of mud to apply with my 6" drywall knife, fold the paper use the edge of the knife to gently seat the fold of the paper into the corner. I then do a light pressure swipe down each side of the corner with the knife at at very low angle and then more pressure on the next swipe. Its all about getting the correct amount of mud and a feel for the correct amount of pressure. – Alaska Man Mar 17 '17 at 17:04
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While the mud is still wet, any knife stroke will slide the tape if not enough squeezing force is applied. What this squeezing does is press the excess mud from behind the tape; the less wet mud, the more friction between the tape and the drywall facing, and the less sliding/wrinkling is possible.

I have never used a corner trowel for taping, and I think that it might be the reason you're wrinkling the tape. It might not be squeezing enough mud from behind the tape.

To squeeze the tape with the least amount of possible damage to it, place one 6" knife corner in the inside corner, tilt the blade 45 degrees or more toward the direction you're pulling it, then apply enough pressure while drawing the knife that the mud squeezes almost completely out from behind the tape, taking care not to tear the corner crease with the knife corner. Then repeat on the perpendicular side of the corner.

My method once the mud is up is to apply the tape lightly over the whole length, then draw the knife upward over the top couple feet, holding it in place with my free hand. Then once the top couple feet is good and tight, I step off the ladder and finish by stroking downward the rest of the way: the top couple feet is stuck hard enough that the tape won't slide.

Sorry if you wanted specific instructions for the corner trowel - but I'm pretty sure that the trowel itself is one of your drawbacks.

1

try using your other hand on the top of the corner trowel and firmly press your finger into it pushing so it reaches all the way into the corner (the sides will flex a little) more like guide the trowel by the handle and push your with other hand down the corner.

0

I have a few suggestions which may help you.

Try to use a standard putty knife instead of the corner one to apply the tape. Once the tape has dried in place, then you can use the corner one to apply the finish coats. A 4" one is a good size to start with.

Start from the top and work your way down. Don't try to work against gravity.

Only use enough compound to stick the tape to the wall. When you apply the tape, make sure to squeeze out any excess compound from under the tape and scrape it off the wall before it dries. This will reduce the amount of bubbles in the tape and it will dry faster.

Don't apply any more compound until the paper has dried completely. This will prevent it from tearing, or peeling up.

If there are big gaps in your drywall (over 1/4"), don't just tape over them. Fill it in as best as you can with compound and let it dry before applying the tape. This will reduce the chance of the joint opening up in the future.

After you apply the finish coat, use a wide putty knife to blend the corner into the existing wall. This will give you a more consistent finish.

  • Thanks, but I'm not looking for alternate approaches. I'm just trying to figure out what I did wrong with this specific approach. – Tester101 Mar 2 '15 at 21:22
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...and then there's the heretical approach. I'm not a fan of the traditional corner. So the last room I did, I used a small plastic bottle (2" dia) to cove (radius) the inside corners. Slopped some mud into the corner with the 4" straight knife, ran the bottle along at a slight angle to press the mud in place, moved excess squeezeout to fill any gaps and re-ran the bottle until each section was smooth. There is mesh tape in there as well.

As (pretty much) expected, the first coat looked like crud as it (slowly) dried and shrank. Forged ahead. Used a sanding screen wrapped around the bottle to knock off the high points, and recoated to fill the cracks. By the second coat it was pretty much maintaining a decent surface when dried. You get a line where the bottle rides, and just need to trowel from that line for the wall surface, letting the bottle do the rounded surface and the trowel do the flat ones. triple-corners (ie, wall, wall, ceiling) did take a little finessing with the way the bottle was rolled into them to get a nice look. I really like the result.

  • Thanks, but I'm not looking for alternate approaches. I'm just trying to figure out what I did wrong with this specific approach. – Tester101 Mar 2 '15 at 21:22
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Drywall Banjos will put exactly the right amount of mud on the tape (a little too much). Extract the desired length and then tack it up using a standard taping knife.

Where appropriate, such as at the ends of the tape, use the knife like a plow. The excess mud will be extruded and scraped off in the same motion. Angle it just a tiny bit away from the wall so the corner of the trowel doesn't bite the tape and tear it. -Sometimes the ends just don't work for me unless I use the trowel backwards.

Finish one side at a time, unless you can make perfect corners in one swath; that's what a corner trowel is for, not taping.

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Ebay

I can't mud without one and I've never seen a pro use a corner trowel.

  • I haven't seen any of my pros use this in at least 15 years. Do you think they save you time? – DMoore Mar 2 '15 at 21:14
  • I don't think I'll be doing enough drywall finishing to justify purchasing a banjo. – Tester101 Mar 2 '15 at 21:18
  • I suck at mud too, unless I take the time to load one of these up. 'Pros' I've seen have the kind that fills with a pump on the bucket. One like that would save time and headaches. – Mazura Mar 2 '15 at 21:31
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Try this, Mud, use minimum pressure on the corner trowel to level the mud, remove extra from the trowel, embed the tape by hand and then use the corner trowel to fully embed the tape and smooth your edges.

0

If you are using mud straight out of the bucket or box it is too thick to do your taping. your mud should just thick enough to stay on your knife. Use you fingers to press the tape into the mud. I use a corner trowel but it take to passes to set the tape into the corners then use your knife to feather out the edges. The pro's will thin there mud the moisture in the mud will be transferred into the tape and make your knife slide across the tape smother, not wrinkling the tape.

  • 1
    Hello, and welcome to Home Improvement. This seems like good info, but it's hard to understand; would you spend a couple of minutes editing to make it clearer? Thanks. – Daniel Griscom Dec 12 '18 at 17:22

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