# rock lathe



## waynech (Feb 25, 2009)

It could be a benefit to leave the paper on if its in good shape because you probably have horse hair plaster which makes it difficult to bring the walls to a smooth finish. What you could do ( only if the wallpaper is in sound condition ) is to prime walls with an oil primer, patch any flaws where paper is ripped and then finish coat with latex wall paint.
Sometimes by leaving old wallpaper on walls is the safest, easiest and best way to complete job.


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## quilt sister (Mar 10, 2009)

Thank you for responding to my question, I am trying to look at all options. I would like to keep the work to a minimum as this is to make the home more marketable.

I will take a look at the paper, I suspect it may be vinyl. I'm not sure if that kind of paper can be painted over. Do you know if this is possible ?

Years ago I saw a type of wallpaper that was meant to be painted over. At the time it had some raised design on it, I'm not sure if such a thing exists anymore.


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## RDS (Feb 29, 2008)

I'm not an expert on this stuff by any means, but isn't it pretty unlikely you'd have horse-hair plaster over rock lath? My understanding is that horse-hair plaster was typically applied directly over *wooden* lath, and pretty thick. Rock lath, by contrast, was a gypsum (not wood) sheet product that they then put a thin topping coat of plaster over.

In other words, if you're sure you have rock lath, then chances are the plaster will be in good shape for painting if you remove the wallpaper. I've done that in my current house with rock lath walls.

My old place in Boston had horse-hair plaster walls and it's true, they're a big pain to get smooth after removing wallpaper. On the upside, the wallpaper came off very easily, but that depends to a large degree on the state (and age) of the paper and glue.

Personally I think even if the walls are not perfectly smooth, it looks better if you paint the plaster rather than painting over wallpaper. Yes it's more work and creates more mess, but on the other hand the oil-based primer you'd have to use over top of the wallpaper is pretty toxic and smelly. And if it turns out your wallpaper is not in as sound condition as you thought, the weight and moisture of the paint may start to pull it off the walls.


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## quilt sister (Mar 10, 2009)

Now you have me wondering... I just assumed it was rock lathe. This house was built in 1910, perhaps it is plaster with horsehair. I know it has those skinny horizontal boards underneath.Their is only one layer of wallpaper on the wall and has probably been there since the 60's or 70's. It was that white on white strip ( now off white and lifting on the edges ) and feels like vinyl. It never seemed like a big deal when they stripped the paper off the walls before repapering.

I do remember the walls being poreous looking..my Mom alway said they couldn't be painted but that was her opinion. I don't think she liked painted walls. 

For the purposes of updating (before putting it on the market, ) I was hoping to just strip the paper off, prime the walls and paint. I don't want to have to skim coat the walls first. Is this possible ? I don't really want to repaper and it looks shabby/dated. any suggestions ? My sister and I were hoping to do the updating ourselves. 

The next room will be the upstairs bathroom, a new vanity at the very least. Fortunately the kitchen is in good shape.

Thank you in advance for all your help, it is much appreciated.


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## RDS (Feb 29, 2008)

quilt sister said:


> Now you have me wondering... I just assumed it was rock lathe. This house was built in 1910, perhaps it is plaster with horsehair. I know it has those skinny horizontal boards underneath.


I'm pretty sure they didn't have rock lath in the 1910s, so in that case it's much more likely to be horsehair.

If the paper looks shabby and is already lifting at the edges, and there's only one layer of it, I would say go for it -- strip it. Then you can see what state the walls are in underneath. Then decide whether you think you can get by without a skim coat.

When you strip the paper, make sure you get all the glue off the plaster. Then use a latex primer and paint. If there's still glue on the walls, the water in the primer may activate the old glue, which you want to avoid. Either get all the glue off or use an oil-based primer. But if you can avoid the oil-based primer, you should -- it's bad for the environment, bad for you, and more of a pain to clean up.

To skim coat or not? Depends how perfect you want the walls to look. My place in Somerville had imperfect walls but painted, they still looked 100% better than with old wallpaper. But that was Somerville. If all your neighbors' houses have perfectly smooth walls then, for purposes of selling, you might want to get a pro to skim coat them before you paint.

Good luck.


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## waynech (Feb 25, 2009)

I have owned a couple antique homes in Ma. of which I used to strip all wallpaper off the walls. Before I continue let me just say that I am a professional painter. I found however it is not always the best way to go. You have no idea what the walls look like underneath. You also don't know if wallpaper was applied properly. ( my guess it was not ) By the time you remove wallpaper and find out its horsehair and looks like hell, you could have primed with oil. (yes smelly ) Also if it is rock lathe, that can also sometimes be a horror show. Rock was put up in 2 x 4 sections then plastered over. When wallpaper is removed after years of bonding over Rock you could find cracks around the whole room every 2 x 4 section. Some people think that it is not professional to prime over wallpaper but their is a product, a liner, similar to wallpaper sold for this specific purpose.
If you decide to leave paper on, I would rip any loose and peeling paper, then prime with an oil base primer. Next you patch where seams of paper are noticable and any other areas that need it. Sand patches, spot prime and then paint. 
In my opinion, both of your options in this forum will work.
Good luck.


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## Matthewt1970 (Sep 16, 2008)

If you paint over wallpaper, you will spend more time wishing you had removed the wallpaper than it would have taken to remove it. You are still going to have lines in your wall.


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## waynech (Feb 25, 2009)

obviously you have never worked on old homes with horse hair and rock lathe. As I stated earlier, it depends if the paper is in solid shape and I also stated that the seams would have to be patched. With-out seeing the walls the homeowner has to make the call.


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## Matthewt1970 (Sep 16, 2008)

waynech said:


> obviously you have never worked on old homes with horse hair and rock lathe. As I stated earlier, it depends if the paper is in solid shape and I also stated that the seams would have to be patched. With-out seeing the walls the homeowner has to make the call.


Gee, lets see, most of the houses around here are only 200 years old, so no, I have never run across horse hair plaster. :thumbsup: The original poster never mentioned seeing any hair. Most times horsehair plaster will have a finish coat over it that does not contain hairs. You guys all just assumed she has horse hairs sticking out of her wall.


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## waynech (Feb 25, 2009)

The homeowner stated that the house was built in 1910 and I believe that rock lathe was not introduced until around 1950. HO also said that slats were noticeable. I think we should agree to disagree.


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## concretemasonry (Oct 10, 2006)

I had house that was built in 1917. It had 10" hollow clay tile blocks with stucco on the exterior (original and still there).

Inside the tile was a full 2x4 stud wall (filled with pld fibers and horse hair) with a lath and plaster coating. On that was a plaster "china coat" (about 1/16" thick , perfectly smooth and hard as nails). If it actually, is a china coat, do not touch it if the house has nay importance and plaster is not cracked.

I did find some interior plaster walls with a china that were papered over in 1918 and made the mistake of papering over them in 1970. Fortunately the next owner has enough sense to properly stripp all the paper off and restore the walls.

The exterior walls never had to have extra insulation added because of wall system and the thermal mass - no matter what the ignorant pink panther said.

Dick


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## Wildie (Jul 23, 2008)

my house, built in 1948, has plaster board panels. These are 16"X48" . A rough coat of about 3/8" thick was plastered over this! Then a hard finish coat was applied over this!
In my area plaster board has been used since before WWII. 
Horse hair was mixed with the rough coat quite often, before this! Then the hard, smooth (putty coat) was applied over this!
I've seen cases when the wall paper was pulled, the whole works pulled down, because the rough coat had lost its hold in the space between the lath!

I bought my present home, 3 years ago and had the chore of removing wall paper that had been painted over! I would have gladly strangled the person responsible for this! I think that painting wall paper is the ultimate sin!

However, in an older home, there is a real danger of pulling the plaster down, then you are looking at a major repair job!


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## Gary in WA (Mar 11, 2009)

My house too has plaster walls, of 1910. Here is a very interesting article with dates from GBAR: http://www.nps.gov/history/hps/tps/briefs/brief21.htm


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## Wildie (Jul 23, 2008)

GBAR in WA said:


> My house too has plaster walls, of 1910. Here is a very interesting article with dates from GBAR: http://www.nps.gov/history/hps/tps/briefs/brief21.htm


 Heyya! Thatsa great link! Thanks!


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