Posts Tagged ‘torque’

Another Reason to Not Let the Contractor Prep the Walls for Paper

May 10, 2018


Folks, please do NOT let your contractor or painter “prep the walls for wallpaper.” They simply don’t know how to remove wallpaper properly, and they don’t know what is required to prepare the surface for the new paper. Do a Search here (upper right corner) for more examples.

In this case, “I know that he removed the old paper, because I saw piles of it on the floor,” said the homeowner. But this photo proves that he didn’t. Nor did he bother to remove the towel bar, because when it was removed later, you can see the old wallpaper still under it.

I put the original wallpaper up back in the ’90’s, so I know that, with my good primer underneath, with a bucket of warm water and a little time, that paper would have come off easily and left the wall in perfect condition for new paper.

Instead of properly removing the old paper, this contractor skim-floated over it. That’s the thick white stuff you see in the photo. After sanding the wall smooth (which he did OK in most of the room, but, as usual, did a less than stellar job in corners and around moldings and door trim), he should have removed dust from the walls with a damp sponge – but virtually no contractor bothers with this step.

Removing dust is crucial, because if dust is left on the wall, it may hold up OK under paint, but when wallpaper is applied on top of it, when the paste dries, the paper shrinks a tad and puts torque / tension on the wall. When the walls are dusty, there is the potential for the surfaces to delaminate (come apart), leaving you with seams that gap and curl back. These cannot be glued back down, because the surface underneath is unstable and provides nothing for the paste to adhere to.

So next the contractor primed the walls. There was no mention of what primer he used. But I can tell you that primers formulated for paint are not advisable under wallpaper. PVA-based primers are commonly used under paint; they are designed to keep the paint from flashing. But they are soft and don’t provide a stable surface for wallpaper.

Primers formulated for wallpaper are designed to 1.) adhere to the underlying surface, 2.) provide a “crystalized” surface that the wallpaper paste can bite into and grab ahold of, 3.) provide a surface with “slip,” which will ease installation of the new wallpaper, 4.) allow for easier removal of the wallpaper later, with minimal damage to the wall, and 5.) withstand the torque / tension created by the drying wallpaper.

Ask a contractor or painter if he knows any of the information in the paragraph above. You will receive a blank stare.

All more reasons to NOT let the contractor prep the walls for paint.

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A Good Reason Not to Double-Cut

April 10, 2017

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A double-cut is a paperhanger’s term for splicing two strips of wallpaper together. The edges of the strips are overlapped about 1″ on the wall, and then, bracing against a straightedge, a sharp razor blade and plenty of pressure are used to cut through both layers of wallpaper. Remove excess paper from both layers, and you have a perfectly butted seam.

The only problem is that it’s virtually impossible to do this without scoring into the wall, slicing through the top layer (or more). This cut makes the surface unstable, and when the new wallpaper dries, it shrinks and puts tension (torque) on the wall’s surface. This shrinking and tension can cause the wall to split and curl back, leaving a gap or a gaping wallpaper seam.

This is what you see in the photo.

To remedy this, I wanted to bridge the gap with something that would move with any shifting in the drywall, and that would not cause ridges under the new paper.

The new wallpaper was a thick, textured material, so I was not overly worried about ridges from the patch telegraphing through it.

I used strips from the paper backing of the old wallpaper / grasscloth I had just stripped off the wall to cover the cut wall areas. I tore the patches, rather than cutting, because the “feathered” edges of the torn paper would be less noticeable under the new paper than a sharp, straight edge would be.

The strips were wet from having been stripped off the wall with water, and the wall’s surface had damp paste residue remaining on it, so the patching strips adhered nicely to the wall surface.

But, to be sure, I brushed on Gardz, a penetrating sealer and “problem wall solver.” It soaked in, bound the surfaces together, dried, and made a taught, strong surface for the new wallpaper to go over.

Still, I made sure that my seams did not fall in the same exact spots as these compromised areas of wall. That greatly reduces the possibility of seams in the new wallpaper from curling back or pulling away from the wall.

As it turns out, because of the way I engineered the wall and various other factors, I did end up doing a double cut splice over this door. But I made sure it was not in the same place as the compromised wall surface. In addition, I protected the wall by putting a thin polystyrene (plastic) strip under the wallpaper before I cut, so that when I pressed my razor blade hard to cut through the two layers of cork, it did not damage the wall. Sorry, no pics, but there are other photos of that process on my blog, if you want to do a Search.

Paint Not Adhering to Wall

October 22, 2015
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I am working this week in an expensive new home in the Museum District of Houston. The whole house was built with Green Board, which is supposed to be more resistant to water and moisture than the traditional grey drywall. It was then painted with one, or maybe two, coats of builder’s flat – which is an industry code word for pretty cheap paint, not to mention that no primer was used.

The homeowner used blue painter’s tape to post wallpaper samples. Well, when the samples and tape were removed, look at how the paint came right away with it! The problem for me is that I fear the surface may be unstable, and once the wallpaper is up, as the paper dries, it shrinks and puts tension (“torque”) on the surface below, and if the surface is unstable, it could cause the paint to lift away from the walls at the point of torque, which means all along the seams.

To try to prevent this by stabilizing the surface, instead of my usual wallpaper primer, I am priming the walls with two coats of Gardz, made by Zinsser. Gardz is cool stuff. It is thin and watery and takes some getting used to while applying it, because it wants to run and drip and slop all over the place. But that thinness is what is so good about it – it is designed to soak into porous surfaces, and then it dries quite hard and actually binds things together, and also is pretty impenetrable to water.

What I am hoping is that it will soak through the flat paint and bind it to the Green Board below, while at the same time creating a hard, intact surface for the wallpaper to adhere to. Because water can’t pass through it, I shouldn’t have to worry about moisture from the paste causing any swelling or reactivating of the paint or Green Board. Another benefit of Gardz is that it does all this while still being water-based, so it’s easy to clean up once you’re finished.

Disguising a Bowed Wall

October 4, 2015
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When hanging wallpaper, you (generally) never wrap a full-width strip of paper around an inside corner. Instead, you cut the piece into two strips, measuring and trimming carefully so the first strip will wrap about 1/16″ around the corner, and then you butt the second strip into the corner, overlapping that little bit that is wrapped around the corner.

One thing that can throw the pattern match off is if the wall is bowed. Then a differing amount of the pattern could wrap the corner at the top of the wall, compared to what appears at the bottom of the wall. That is what happened here. The pattern matches perfectly in the corner for the first 7.5 feet (not shown), but begins to gap as you get close to the floor.

Twisting the paper to conform is not an option, because it causes wrinkles, creates torque, and distorts the opposite edge, making it difficult for the next strip of wallpaper to butt up correctly.

Thus, we ended up with this slightly mis-matched pattern in the corner near the bottom of the wall. (Photo I) To keep this mis-match from jarring the eye, I dug into my trusty stash of craft paint, found my tiniest paint brush, and filled in the gaps. (Photo III)

Vinyl Wallpaper and Un-Straight Walls

June 1, 2015
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OK, a lot of technical stuff coming up, and a little hard to follow, but I will do my best to explain. Here I am hanging a faux-leather, textured paper-backed solid vinyl wallpaper with no pattern to match. In the left side of the first photo, I have just come from left to right around an outside corner. When you wrap wallpaper around a corner, you can bet that the corner will not be straight or plumb and the wall may even be bowed. That means that you cannot expect the right edge of this strip of wallpaper to be straight, and that means that you cannot expect the next strip of wallpaper to butt up perfectly against it.

Since this paper has no pattern to match, the solution is simple, if not easy. I am going to overlap the next strip and splice it in with the previous strip. But you don’t want to just overlap and slice through both layers with a razor blade. Doing so could: 1.) get paste on the surface of the first strip, which, since it’s a textured paper, would be hard to wipe off, and, 2.) score the wall, and that means that when the paper dries, it shrinks and puts “torque” on the seam / surface – and that could cause the surface to pull away from the the subsurface – keep in mind that here we have Sheetrock, paint, new paint, and wallpaper primer, one on top of another, so there are several layers that can all pull apart from one another. To put is succinctly, the end result is a curled seam – which cannot be glued back down.

So, in the first photo, in preparation for the double cut (splice), I have put a “Boggess pad,” which is a long flexible strip of polystyrene plastic under the seam, to protect the wall. You see a bit of it peeking out on the right side of the photo, and you see the ridge it makes under the paper in the center of the photo.

On the right side of the second photo is the new strip of wallpaper, coming to meet the existing strip. Along the edge of this new strip of wallpaper is a strip of waxed paper, and you can see some of it sticking out on the left edge. This waxed paper will protect the existing strip of wallpaper from the paste that is on the new strip of wallpaper.

In the third photo, the metal tool with the pointy top on the left is a special straight edge that I use for cuts like this. I have already made the cut along its edge, and you can see both the cut and the waxed paper on the left side of the cut. You can see a little bit of the hump created by the polystyrene strip under the vinyl paper, on the right.

In the fourth photo, I have pulled the vinyl strip on the right back a little, so I can pull off the waxed paper from under it. The polystyrene strip is still against the wall, under the vinyl paper on the left. I am about to remove that, too.

All this has taken some time, and another factor playing in here is “open time,” which means how long the paste will stay wet and allow you to fiddle with all this.

In Photo 5, I am about to smooth the two edges of the seam back together.

In Photo 6, you see how perfectly the edges meet. A double cut (splice) really gives you the most perfect seams, because the two pieces of paper are truly melded together. It does take a lot of time and materials, though, and is not really called for except in certain situations.

This room turned out looking great, and the homeowners were pleased. The homeowner did ask me why my price was higher than the guy who had hung paper in another room. From what I saw, the other installer did a good job in that room.

But I’m wondering if he has knowledge of primers and layers of wall surfaces and torque and open time, and if he has waxed paper on his truck and knows when to use it, and if he has a special $125 trim guide and knows how to use it, and if he has ever heard of a Boggess strip or if he just cuts into the wall and hopes it all holds together.

Bottom line … sometimes special situations call for special tools and equipment and skills.
Not saying another guy couldn’t do it his way and have it turn out looking great.
Just saying I’m glad I have these gadgets to use, and the know-how to use them to keep the homeowner’s wallpaper clean and unwrinkled.