Smarten Me Up Re: Plaster/Drywall

I have a few suggestions, they may be obvious - or not.

Have the Drywall taper, if you hire one, wet the paper tape before he applies it to the seams. Yes, it does make a difference. The tape will NEVER peal away from the surface like dry paper tape does, as it is in my house from a cheap renovation in 2001. This is between new and new dry wall.

Where the new drywall addition meets the old plaster wall, besides trying to get them at the same surface level, with various tricks (shims, an extra layer of drywall, etc) treat the seam like this;

first, use the powder joint compound and mix it yourself. It comes in various working time formulas - 90 minutes, in small batches works fine. Don't use the ready mix, it ends up being softer than the you-mix-it kind and what you want is something that resembles plasters hardness without the hassle of actually mixing plaster and working with it. Its not equal to real plaster, and I'm not saying it is, but for the DIYer this way is manageable and you get better than the standard schlock finish.
Next, in the roofing section at HD or Lowes get the fiberglass mesh tape that's supposed to be used on the roof with roof tar and use that instead of paper tape for the seams. Its wider, cheaper and actually works great to hold the two different surfaces together.
So...
adjust wall surface levels
skim coat big differences in the seam area with 90 minute joint compound, let dry
skim seam again, and embed roofing tape into the joint compound to fully cover the seam, let dry. Don't worry about some of it showing through, you want to really push it into the compound and embed it, getting it as flat as possible on the wall. More, Thinner coats are better than, make my money as fast as possible, goodbye fat coats.
skim coat again, let dry.
first sanding. if you see any imperfections, and you will, vacuum the wall, wipe it down - get a spray bottle with water and spray the wall where the imperfections are and reapply another skim coat, dry, sand, you get it - till its perfect.
I know, sounds like a lot of work. I did this exact same thing when I tore out a doorway and moved a lot of walls and ceilings to new locations where I had to match up old and new. It took a while, but its my house now and it needs to be perfect (I'm cursed!)
You cannot see where the work was done at all.
Patience, practice and pride for the time you put into it will reward you in the end.

Hope this helped a bit.

Posted by: guest at November 15, 2007 2:30 PM

Wow, thanks for the post.

I am definitely not doing it myself--there are other things to do, and I will feel like such a turd looking at my bad skimcoat job for years to come... it seems worth the effort.

But this is helpful for talking to the person I hire... I want to know going in what their strategy is for blending old and new, and this gives me some specifics.

Thanks!

Posted by: guest at November 15, 2007 2:58 PM

I live in very old house with plaster walls and sheetrock ceilings. I skim coated the ceilings myself with diluted lightweight joint compound. IMHO, the key is a substance called plaster-weld, which you might already know about. This stuff--it's pink--helps the joint compound stick. Also, to fill gouges/separations/holes, I use newspaper saturated with joint compound, really pack it in, let it dry, then smooth over with more joint compound. As a final suggestion, use an eggshell-finish paint. It gives a plaster-esque texture to flat sheetrock.

Posted by: guest at November 15, 2007 7:15 PM

call luis!

Posted by: guest at November 15, 2007 11:13 PM

This is the OP. First of all, I called Luis, and he made an appointment to show up at my house and didn't come and didn't call, so feh on Luis.

And yeah, Mr. Legs, I agree.

Posted by: guest at November 16, 2007 4:34 PM

I actually prefer fibermesh tape over paper tape - and I have done drywall work as a professional. If drywall is eventually cracking badly due to settling, you've got bigger problems to worry about.

There's actually a greater chance that the paper tape will come off the wallboard, especially if it wasn't applied just right. (Don't let any dust get underneath.) I've used both as a pro, and now I would only use fiber mesh...

Skim coating is always the best way to go - You will have a completely consistent surface with no wallboard "bumps" on the paper coating showing through, and your primer and finish paint coats will be absolutely consistent. And you won't see those horrible paper scuff marks like you see in shitty new constuction where they DON'T skimcoat.

Also, I never thin the joint compound when skimcoating. It's already the perfect consistency to work with...

The key is to build up three, sometimes four layers of compound over all seams - sanding carefully between each application. When you are done, you should not be able to tell where any seams are, even if you "rake" a light across the wall at different angles. (which I recommend doing so you can see if you've missed a spot that needs additional compound and sanding.)

Getting rid of stucco textures can be a real pain in the ass. You can try scraping off the high spots with a thick drywall knife (which is not technically a knife but a trowel) and then skimcoating several layers, but in some cases it might be easier to simply apply veneer drywall (3/8") over the rough surface. I absolutely love that veneer stuff - lightweight but saves a ton of work when restoring walls in bad shape.

Unless you are doing a real plaster restoration...

Posted by: guest at November 17, 2007 3:09 PM

Go to www.masterofplaster.com I have used there product to restore plaster walls and they came out perfect.No bonding coats , no sanding and no dust every thing is smoothed out with a water mist bottle.Check out there site look at the before and after,the guy who makes the product has been in the business over 50 years

Posted by: guest at November 17, 2007 4:21 PM

3:09, thanks! This is exactly the information I was looking for!

Now I just need a plaster guy who returns my calls...

Posted by: guest at November 18, 2007 11:00 AM