How to Skim Coat Walls with the Best of Them.

Here’s how to skim coat walls with the best of them: hire the best of them? OMG YOU GUYS I FIGURED IT OUT! Are you inspired yet?

I’m the worst.

But here’s the deal: renovating a house involved a LOT of different technical skills, and you don’t have to walk into it with any of them, really. I didn’t! And while I think it’s good to dip your toe into all sorts of things to learn how they work and whether you actually like them, after you’ve done that I think it’s OK to be honest about what you find enjoyable/gratifying and cut yourself some slack on what you don’t. For me, I’ve found that I really enjoy some woodworking/carpentry times, basic electrical, tedious crazy tasks that wouldn’t really make financial sense to hire out (removing and planing down all the original clapboard on my house, for instance!), and plenty of other things like painting and restoring windows that’s neither fun nor un-fun but manageable and fine and kind of satisfying. And then there are other things that I have very little interest in, like plumbing and, you guessed it, skim coating. I love a restored plaster wall. I don’t want to restore all my plaster walls single-handedly. I like parts of it (stripping down the plaster, installing plaster washers), but the actual skim-coating part I’m thrilled to hand over to a pro when I can. I can do it. I don’t want to do it. So for the den-ovation (thanks to Jaime for that delightful word combo that I will shamelessly co-opt), I hired my main man Edwin to take on the bulk of it. Lucky for you this freed up my hands to take some process pics which we will now review. Let’s learn from the best in the hopes that we might someday be the best? Or just be OK with not being the best. Up to you.

THIS GUY. I love him with all my heart. He’s straight, just to clear anything up there. Edwin is my next door neighbor who I hired three years ago to install/mud/tape drywall on my first floor ceilings, and we’ve done a ton of stuff together since. It’s the most significant bromantic relationship of my life. I learn a lot from him and, believe it or not, he learns a lot from me. Life isn’t all sunshine and rainbows, but when Edwin and I work together it kind of is. Except that time I dropped a level on his head. Sorry Papi!

Also, what a stud. He likes to inform me multiple times a day that “in my country, they call me El Pollo.” Of course they do.

SO. Let’s talk skim-coating. I should preface all of this by saying that we’re talking specifically about skim-coating with joint compound, which is a bit more DIY-friendly for someone who’s not used to doing it, but IDEALLY we’d be talking about a plaster veneer. Plaster veneer falls into two camps from what I understand: hydrated lime and gypsum-based. Gypsum based plaster veneers are generally available at big boxes and the like, and are generally what people are talking about when they talk about plaster veneer in the United States. It sets VERY fast, dries VERY hard, and is super beautiful (especially when tinted and left unpainted!), but traditional plasterers typically apprentice literally for YEARS before they’re allowed to start “putting up” plaster on their own. It takes a lot of skill just to get the plaster from hawk to trowel to wall, and a lot of built-up muscle memory to get the application just right.

Hydrated lime plasters are WAY cool, and what I’d like to try next. It’s one of the oldest building materials known to man and remains one of the healthiest to live and work with. It has the ability to handle big swings in humidity and temperature, which is good in old houses that undergo these swings due to a lack of central air and modern ventilation and stuff. Lime plaster is essentially extremely finely ground limestone that’s fired at a temperature of about 1500 degrees to remove any impurities, and then some other stuff is done to it that I don’t pretend to understand, and then it arrives to you pre-mixed in a 5-gallon bucket. Whereas gypsum-based products have a shelf life because the wet varieties dry out and the powdered varieties take on moisture from the air and harden, hydrated lime is actually aged after packaging to achieve superior results. Once the hydrated lime is applied to interior surfaces, it takes CO2 from the air to “cure”—essentially completing the lime cycle and returning to a stone-like state on your walls! How cool is that? Application technique dictates whether your walls are kinda rough and uneven or perfectly smooth and shiny, which is just personal preference. Instead of sanding like with joint compound, you keep working the plaster as it’s curing to smooth out it out to your heart’s content. Cure/working time is similar to the dry time with all purpose joint compound, meaning it’s typically a three-coat process spread out over three separate days, and like gypsum plaster veneer it can be left painted or unpainted depending on taste. Also it dries to a PH of 12, making it naturally mold and mildew proof. This is why you can wet the shit out of an old plaster wall to remove wallpaper and stuff, and the wall is totally fine.

So those are some things I know—huge thank you to the folks at Master of Plaster for teaching me. They sell gorgeous restoration plasters which can be colored to your preference, and I’m so excited to try it out someday soon.

We didn’t do that though. I have zero doubt that Edwin has the skills to pick up plastering quickly from all his years of joint compound work, so we’re gonna learn it together. Then he can start charging an arm and a leg to do real plaster restoration work, so it’s a win-win! As long as he doesn’t try to hit me with those new rates, haha.

SO. I digress. We are talking about joint compound, the inferior but totally fine/normal way to do this.

Once the plaster is stripped down, plaster buttons installed, and cracks scraped out, the next step is applying fiberglass mesh to the cracks. You CAN do the window screening we discussed in the last post over the entire wall (particularly if there’s significant cracking), but mostly the walls in this room were in good shape so we used standard mesh tape just where it was needed.

I do NOT like paper tape. I feel like it doesn’t hold up, particularly on plaster. I don’t trust it.

We always end up using some combo of joint compounds for skim-coating, which is something you mainly just need to get a feel for. The All Purpose pre-mixed joint compound 5-gal bucket is fine, but the dry time is quite long (sometimes more than 24 hours, depending on temperature and humidity levels), and I don’t think it dries to the same hardness as some of the powdered alternatives. When I’m doing it myself, I tend to go for Easy Sand with a 90 minute set time, which for me is enough working time (now, not when I first tried this!), dries harder, and—as the name implies—does sand easily. Because Edwin has better technique than I do, for this we primarily used Durabond—also a joint compound but dries really hard, making it probably a poor choice if you rely on a lot of sanding like I do when doing this myself.

It takes some practice to get a sense of the right powder-to-water ratio, but you can always add a little more water after mixing. We tend to mix maybe a third of the bag at once. You’re going for a thick peanut butter type texture.

There aren’t really right and wrong ways to get it up onto the wall. I’m now OK with a hawk and trowel, but I started with a mudding pan that felt more manageable. You’ll notice that Edwin has a rounded trowel in his right hand (typically used more for plaster than joint compound) and a straight 8 or 10 inch taping knife in the other. He was excited to try the rounded trowel but he’s used to the taping knives. The benefit of the trowel is that the rounded edges make it easier to not leave lines, but personally I find the trowel difficult to get the hang of. Also of note—those dark patches are fiberglass window screening that we used over the upper section of wall where the plaster was more iffy.

Essentially you want to load up your trowel or knife, start at the top and smooth it all down (or bottom up, or side to side—whatever the hell makes you happy)—you’re looking for about 1/8″ in coverage or a bit less. Thin! But also thick enough! The key is to apply the right amount of sturdy, even pressure to the knife or trowel to get a smooth, solid skim rather than one with bubbles and other weirdness.

I find this difficult. The Magic Trowel makes this less difficult, but you don’t want to really rely on it—you still have to get a FAIRLY smooth and even coverage with the knife/trowel, because the Magic Trowel is really good for smoothing and filling in tracks left by the knife or air bubbles, that kind of thing, but not for actually getting joint compound up onto the wall.

Obviously, the wall on the left has a coat of compound on it, wall on the right does not. There are knives for finishing both inside and outside wall corners, but Edwin prefers to run a straight taping knife along one side of the corner, wait for that side to dry, and then proceed with the adjoining wall and its side of the corner. Trying to do both at once with this method will lead to some very messy corners.

See how there’s some yellow peeking through the grey joint compound to the left of the door? That’s kinda what you’re going for with a first coat in terms of thickness. I won’t pretend it’s easy.

After the first coat is up and fully dried, go around with your taping knife or spackle knife and knock off any high spots or weird globs. You don’t need to sand at this stage but you do need to get your surface even for the next coat.

Ugh, melt my heart!! Look at him go. This is the second coat going up. The second coat is when things really start feeling covered, much like with paint.

We all know by now that I am kind of a crazy person (if you’re new here, consider this your warning), so even though it’s totally abnormal, I think skim-coating drywall is something worth considering if you’re in an old house and trying to match up plaster surfaces to drywall ones. It’s NOT about adding weird texture or giving the walls some faux-rustic treatment, just about NOT getting those perrrrrrfectllyyyy flat walls that drywall is really designed for. I think this will also lessen the likelihood of the drywall cracking along the seams or screw heads popping over time, which I see with most drywall jobs after a few years. If you can tell where the joints are, it’s not going to look like a plaster wall.

Will anyone EVER notice this? No. It’s a normal wall that looks like a normal wall. That’s the point. But I will know it was treated the same way as its plaster counterparts in the same room, and I will appreciate it.

Same for the ceiling. You’ll notice for both that we mudded and taped as usual for the first coat, and then proceeded to a full skim for the second. It made my heart go all pitter-patter. Skim-coating a ceiling is my personal version of hell, but Edwin was undaunted. Told ya. He’s good at these things so they don’t seem like a big deal at all. Just another surface.

Look at that! The man’s an artist! I do NOT achieve these results pre-sanding. Or even post-sanding. That is why it’s worth it to me to hire out. It’s faster and easier but it’s also BETTER long-term than what I can do. My work is sufficient. His work is excellent. It’s not like this is the kind of thing you ever want to redo.

I’ve increased the contrast on this picture a bunch so you can see that up close, it’s not perfect. Not yet! This is after the second coat, and there are some track lines from the trowels and knives and unevenness. As with the first coat, you want to knock down any high spots and lumps after drying, and depending on how things are looking you might want to do some sanding. With Edwin we can mostly skip the sanding and just save it for the end. I have to sand when I’m going it alone.

Your final finish coat is primarily to fill in any of that weirdness, and Edwin likes to mix a soupy batch (think pancake batter!) and paint it onto the wall with a roller. It’s nice to have two people at this stage—one to mix and roll and the other to smooth.

Once it’s rolled, you work quickly to smooth it down—taking most of it off the wall as you go. Just enough to fill in pesky spots.

I might need to do this final coat a few times over as I continue to spot imperfections, but a more skilled skim coater can do it in one shot.

After that’s all totally dry, you can move on to the sanding! Confession time: right after I bought this house and was operating under the delusion that I’d be doing all the skim coating work myself, I bought myself this super expensive drywall sander that primarily just takes up room in my basement. It’s designed to hook into a running ShopVac to suck most of the dust, but honestly I find it difficult to control and I don’t like using it myself. Edwin is a big fan, though, and I often let him borrow it for jobs he’s doing. When sanding, even on a bright day, it’s good to shine a work light at an angle on the wall you’re working on—it just helps you see whatever needs to be sanded down.

This doesn’t get you entirely out of hand-sanding, though—you need to go back in with a sanding block around moldings and in corners and areas that are missed by first pass. After a first coat of paint, these seams where the wall meets molding get caulked.

The final step for me is typically knocking down the globs that like to accumulate on top of door casings and baseboards. You can’t see the top of the door casings if you’re just in the room, but I like knowing that these spots didn’t just get painted over because someone (who is me) was lazy.

So there it is, skim coating with Edwin! At this point, the room is pretty much ready to paint! Now I can get in there and tackle the moldings, CLEAN, and get some paint on these walls!

How to Skim Coat Walls with the Best of Them. published first on manhattan-nest.com