A little Off Track, Plastered Walls Very Uneven at Floor

[Jim Foster]

I have a hall that was plastered several years ago, I'm just getting around to trimming it now. The plaster at the base of the wall is thicker and very uneven for the first 3" of the wall. If I rest a 6" square on the floor against the wall, the square will be anywhere from 1/8 to 1/4 of an inch away from the wall at the top of the square all around the room due the thick plaster at the base of the wall. It's more than enough of a defect to show when the trim is applied. Chipping this out with a hammer and thick scraper to get the bottom of the wall plumb is very time consuming. I was wondering if anyone else has had this challenge and found a reasonably quick way to remove the offending plaster?

[John Schweikert]

Only alternative I know of is to hollow out the back side of the trim as needed so it will rest flat at the top edge.

[Mark Bolton]

In all honesty 1/4 to 1/8" isnt too too bad but it would of course be better if it were less. If your really set on fixing it you could grind the plaster down with either a belt sander laying on its side along the floor, and angle grinder with a flap wheel, or something to that effect and then just clean up the corners by hand. Both would be horrendously dusty.

John likely has the simplest idea and that would be to run the base through the table saw standing up with the good face against the fence and taper the base so its thinner at the bottom

Perhaps its worse than 1/4" in places but if it were me Id lay some base in there and make a few copes/miters and see what it really looks like. Id guess when its all said and done it may be less noticeable than you think. That said, if you are going to notice it every day and it will bother you, best to get it straighter.

[Sam Murdoch]

Perfect job for a belt sander - on the trim.

[Tom Ewell]

280521
Looks like to me that this plaster 'rasp' is a press-on nailing plate with a handle attached.

Maybe try a couple of plates attached to a board backer with handle to flatten your plaster.

There are plaster planes but I believe they're used to true up areas before the plaster is fully set.

[Jason Roehl]

Is it actually plaster (not commonly used anymore, at least in my neck of the woods), or is it drywall joint compound?

I ask because I hear many people (especially of a slightly more elderly generation) use "spackle" or "plaster" when referring to drywall "mud". The three are not the same, and would require different approaches.

[Tom Ewell]

If he is chipping and scraping with a hammer, I presume that he dealing with real plaster

[John Vernier]

I know this isn't the neanderthal forum, but one traditional solution for this problem, and one I have used in the field several times, is to use a scrub plane to hollow the back of the baseboard as needed. Some old carpenters will tell you that the #40 Stanley scrub plane was used mainly for that purpose. It is surprisingly fast and easy, even if you are working on a sawhorse, and a lot less messy than chipping plaster.

[Jim Foster]

It's a plaster finish over blueboard.

The right type of rasp might work well, I'll look around

[Mark Bolton]

Your more than likely going to have to sand/grind with veneer plaster. The stuff is hard as a rock and very difficult to sand. If your set on the approach of fixing the wall as opposed to trimming the base I'd think sanding/grinding will likely be your best bet. You'd even get it with a soft pad in a corded drill and some sanding disks.

[Jeff Duncan]

OK a couple quick thoughts, 1st, as mentioned, that's not that bad at all. Or put another way, I routinely see worse:o

#2, the best way to check how far off you are is with a straight edge on the face of the wall. Using a square assumes the floor is somewhat flat and level….both fairly unlikely;)

lastly, as fas as a fix I would not spend the time to try and remove the plaster. It's far easier to back cut your molding and install with a little construction adhesive.

good luck,
JeffD

[Rich Engelhardt]

Old baseboards (for the old real plaster walls they went on) were often 5 to 6 inches wide and made up of many different parts for a good reason.

[Phil Thien]

In older homes, the trim was often installed before the plaster. Here, read this:

http://www.nps.gov/tps/how-to-preserve/briefs/21-flat-plaster.htm

When the trim is done before the plasterers have at it, you get a nice line.

Have any pictures of the wall, and the trim you will be installing?

BTW, grinding the skim coat can be problematic as you have to chase the high spots quite a bit up the wall to avoid a situation where the trim sits into the plaster. Maybe in your case there is just a slot of slop towards the very bottom of the wall?

[George Bokros]

You will need to be careful grinding the plaster down. You may grind through the finish coat and into the gray or rough coat of plaster then you will have a very hard to finish surface likely requiring you to skim coat with drywall must to get a surface that will paint up nicely. The finish coat of plaster is not very thick. When my dad built his house in 1959 the plaster was 5/8" thick, that was the height of the plaster grounds, with the finish coat only about 1/4" to 3/8" thick.

George

[Mark Bolton]

Tons of good info.

Virtually all the work we did back in NE was skim coat blue board and I too had assumed perhaps the skim coat was just fat at the base or even perhaps a roll where the plasterers just didnt pick up the material at the base of the wall. True though, if its long and tapering substantially up the wall grinding it would be out. I would never want to grind a plaster job and then have to patch back with shoddy joint compound. The hard smooth finish of the plaster is what your after and other than compounding out a transition or cold joint I avoid compound.

Our plasterers use to float out the base and door openings with 14" or better smooth trowels and even 30" darby's to get those areas nice and flat resulting in a dead tight trim/plaster joint that was nearly invisible after paint with no caulk. The long trowels/darby would result in any highs or lows being over a 30"-60" area or better which is dead flat for any wall.

The times George mentions were the best, grounds at all openings, nice and flat and clean. But those techniques died in the late 60's to very early 70's in our area.

I wish there were more blueboard and plaster where I am now but its all cheap drywall. No one will pay for it. Its a vanishing trade for the majority of the country.

[Phil Thien]

Thinking about this some more...

I think I'd try to remove any large blobs, apply my moldings, and then have the plasterers come back to fix any gaps by adding plaster.

So my suggestion is to ADD plaster, rather than remove plaster, to fix the issue.

[Mark Bolton]

Thinking about this some more...

I think I'd try to remove any large blobs, apply my moldings, and then have the plasterers come back to fix any gaps by adding plaster.

So my suggestion is to ADD plaster, rather than remove plaster, to fix the issue.

The problem with that is plaster doesn't feather. You simply can't add plaster over old and feather it out to an invisible seam. You have to leave a transition which then had to be feather out with compound.

The only way to do it right would be to re-skim the entire job which has other issues as the new plaster is not guaranteed to bond to the old troweled (hard polished) finish.

This was the case for us because plaster was troweled out like glass.
Rock hard, shinny,... Make a new plaster No sticky

[Phil Thien]

The problem with that is plaster doesn't feather. You simply can't add plaster over old and feather it out to an invisible seam. You have to leave a transition which then had to be feather out with compound.

The only way to do it right would be to re-skim the entire job which has other issues as the new plaster is not guaranteed to bond to the old troweled (hard polished) finish.

This was the case for us because plaster was troweled out like glass.
Rock hard, shinny,... Make a new plaster No sticky

I've seen some pretty amazing work done by plasterers. I'd at least give them a chance to come back and see if they'd be able to help. I saw a spray finish job done a couple of years ago because the previous work was so poor. So the new outfit sprayed plaster (with a bonding agent) and then used a giant feathering rule. It looked awesome. But that was a commercial job and I don't even know what kind of costs were involved. It may have been cost prohibitive for residential.

I'm just saying adding plaster (if it can be done with a good bond, I agree with you that the bond is a giant concern) would perhaps provide a better outcome than trying to grind the plaster.

Or he can have painted trim, LOL. Nuttin' wrong with painted trim.

[James Tibbetts]

My first approach would be to get the plasterer over to see what he thinks can be done. Go from there.

[Larry Edgerton]

It was common practice in old homes [1800's] to run a three piece baseboard. First there was a track on the floor that was a half round on the side that shows with a groove to accept the rabbited baseboard. the top was a cap with another rabbit and this would have a pleasing profile much like chair mold. The main center baseboard itself was not nailed at all but rather floated in the two rabbits. It did not ride on the wall at all till it came to the cap, so the bottom 9 inches or so of plaster was of no consequence.

I have all the cutters to make copies of several styles as I used to do a fair amount of restoration before the EPA screwed with my business.

Larry

[Jim Foster]

Thanks for the suggestions. I would have liked to get the plasterer to look at the mess his guys made, but that time has come & gone. I ended up buying a cheap "bondo" rasp and using that in conjunction with a thick putty knife I used like a chisel to clean up the base of the wall. It turned out to be just the first 1.5" going up the wall. The plaster was so uneven that trying to modify the baseboard trim to fit would have still left me with a lot of chipping and rasping on the plaster, so I stuck to the plaster side of things. I like the idea of having a "floating" baseboard like described above.