Monday, January 4, 2016

Lessons In Mud

I've done some drywall patching over the years but this is only the second full room drywall project I have attempted. I'm getting better but I still have some learning to do.

The first time was when I redid the entire basement at my previous house. I had my brother and father help me but it was the first time for all of us. I bought a self adhesive drywall tape for all the seams but it required lots of mudding to cover it and in-between every coat, we sanded as if it might be our final coat, i.e. we did a meticulous job. Not only did it require lots of time and extreme amounts of effort, it was all undone when we applied the next coat. When we finally finished and thought everything was perfect, we applied paint and of course all the defects that we missed showed up easily. I was so disgusted that I just kept on painting and hid the defects with furniture or pictures.

This time around, I decided to do some things differently. I switched to using the drywall paper tape that isn't self adhesive since it is much thinner thinking that I wouldn't have to use as much mudding compound and thus not have to sand so much afterwards. The second thing I did was to just sand things smooth between coats but not worry about the defects until the final sanding. My thought was that perhaps I defects would hide themselves in subsequent coats and the final sanding would make everything look nice.

In the end, I spent much less time and effort sanding, especially on the first couple coats of mud. I could sand the entire room in about an hour and have it remudded and hour later, much less than the half day I would have spent sanding using my old method. On the final coat I still spent that half day getting everything perfect but since I didn't have two half days before it, I had more pep in my engine to complete the task.

However, switching to the thin paper drywall tape didn't work out so well for me. In short, I got bubbles everywhere. The tape apparently would unstick itself from the mud bed I pressed it into and then dry that way. Then when you pressed on the area after it dried, the bubble would crack and leave a horrible looking scar on the wall. The only way to fix this was to cut the bubbles out with a knife and repatch those areas which I did in about thirty spots around the room. The only thing I can think that may have caused that was that I didn't have enough mud initially spread on the joint so that there were dry spots where the tape wouldn't stick and thus create the bubbles. If I do this again, I guess I would give the tape one more go and see if that fixed the problem because I had less problems sanding through the mud and exposing the tape as I did with the much thicker self adhesive tape that I had previously used.

When I finished prepping the walls and primed them with paint, I found several defects that I hadn't sanded down well enough. However this time I wasn't so worn out from all the sanding so after the primer dried, I simply remudded or sanded down the areas and reprimed them again before I painted the room to the final color. I am pleased how it turned out.


Kelly said...

It sounds like an exhausting, frustrating experience... especially since your goal was to make it easier this go round.

At least the end result was satisfactory. That's what ultimately counts.

Rich said...

I'm far from a pro at drywall work, but I've done a few houses worth of it over the years.

When I do my taping, I usually use an 8" knife (a putty knife) to apply a good thick bed of mud on the joint, put my tape on the joint, then I come back with the knife to apply another layer of mud on top of the tape as I press the tape into the joint. A wider knife is less likely to push as much mud out from under the tape.

After that first layer of tape is all applied, I just quickly knocked down any high spots with either my 8" knife or a sander before applying the next layer of mud.

I usually use a trowel (something like a 10" concrete trowel with the corners rounded off)and a hawk to apply the mud on the taped joints. It takes a little practice to get the hang of using a trowel and hawk, but it's much easier to feather out the edges of your mud. Better feathering means less sanding. A typical drywall joint will usually end up being feathered out to 16-18" wide with a trowel.

On the final coats, adding a little water to thin your drywall mud slightly can help with feathering the edges, which should also cut down on the sanding. Ideally, there shouldn't be much sanding required until after the final coats of drywall mud (at least that's the theory).

All of that is probably what you already knew and a little too late, but that's the way I do it whenever I'm forced to do any drywall work.

sage said...

this is never fun... but if I was too do it again, I think I would see if I couldn't rent one of those contraptions that puts the tape and mud on at the same time... Also, it seems that a lot of the dry-wallers will use a sponge to smooth things out which reduces the need for sanding. It does look like you've done a good job--you can also skip-trowel or splatter the wall to cover up imperfections.

Ed said...

Kelly - The good thing about mudding, is that you can hide a lot of imperfections, especially if you have time on your side!

Rich - I haven't heard of using a float to apply mud but that sounds like a really great idea. I have a hawk and a range of mudding knives but the larger ones I always have difficulty using. I always end up with gouges where I don't want them. I think I would have more control with a stiffer float. Although I hope I don't have to ever use that advice anytime in my near future!

Sage - I have done texturing using sponge rollers and thinned down drywall mud but opted to go smooth on this room, especially since my drywall went up pretty nice. Overall, it turned out great though it was still more work than a pro would have needed to do.

karl o'melay said...

We hate artificial textures but the love the natural random feel of real plaster work. Ahh that subtle eggshell feel of plaster is just the best.

Ed said...

Karl - One of these days I'm going to try my hand at plastering. It really seems like the way to go but I've always been too chicken to try it on a large scale on a wall that everyone will see. I always admire a good plaster texture when I see one somewhere.