Posts Tagged ‘math’

Grasscloth Engineering and Logistics – Technical Details Post

August 21, 2022
Grasscloth is a natural material that cannot be matched from strip to strip, so all the seams will be visible . In addition, there is usually a slight but noticeable color difference between strips / panels (called shading or paneling ) . So it’s important to plot the layout of the strips to give the most visually pleasing overall look. Usually this means balancing the width of strips so they are all equal , at least on the same wall . We call this engineering .
This wall presented particular challenges , due to the widths of the elements. Grasscloth comes 36″ wide . You can use your straightedge and a sharp razor blade and trim it down to any width you want.
The width of both the large wall spaces to the right and left of the bank of windows was 34.” The width of each window was about 35.” The width of the two spaces in between the windows was 7.”
So you’d think I could trim my panels on either side of the windows, and then over the windows, to about 34″-36″ – give or take a few inches (or fractions thereof).
But that would leave me with two 7″ wide strips between these 35″ panels. Although the look would be uniform and mirror-image from the center outward, moving from right to left you’d have: 35,” 35″, 7,” 35,” 7,” 35,” 35,” … those 7″ breaks were just not going to look right.
One option was to determine the width of the wall (189″) and make each strip an equal width. This worked out to six strips, each at 31.5″ Not good, because this would mean a seam down either far side. And since those sides were 34″ wide, that would mean a 31.5″ wide strip and a strip 2.5″ wide. Not attractive at all, and it would use up an extra strip of wallpaper.
This six strips @ 31.5″ wide scenario might also land with a seam smack in the middle of those 7″ wide interludes in between the windows. Not attractive at all.
So I decided to make the two outer strips 35″ wide. That left 119″ of wall space above the windows to be covered with wallpaper. Do some math and you get four panels of 29.75″ wide. This gave a balanced and uniform look to the area over the windows, and also prevented seams from landing between the windows.
Moving right to left, I cut and hung the full length outer strip first. Then I cut and hung the strip over the window on the right. Then I measured to find the centerpoint of the window in the middle. Turns out it was a bit less than 29.75″ away. So I trimmed that next over-window strip accordingly.
Once that was in place, I measured from that center point above the middle window out to where my left full-height panel would fall, 35″ out from the wall. Took the resulting measurement and divided by 2. Lo and behold, each of the next two panels over the window was going to be a bit wider than 30.” No problem. No one (but a paperhanger or maybe an engineer) is going to notice a 1/4″ or even a full 1″ difference in widths between this strips over the windows.
Another thing to point out … it’s important that I took measurements before cutting these strips for this second left-hand section. Because, since grasscloth comes at 36″ (and walls can be wonky), if my strips had been narrower (say, 28″), that last full-height panel on the left might have ended up needing to be 37″ wide – and that wouldn’t work because it only comes 36″ wide – plus you need at least 1/8″ to wrap around the corner.
Luckily I had the flexibility to be able to trim the panels over the windows to any width needed, to accommodate all this.
If you’ve followed all this so far, let me also toss in that we also need to figure how to get paper in between those windows. More on that below.
In this scenario, I’m moving from right to left.
Area beneath the windows needs to be treated in the same way, and preferably with widths that match what’s going on above the windows. In addition, it’s tricky because after you move across 12′ of wall space, the strips above and below the windows are going to twist and torque out of shape, so that last full-length panel on the far left might not butt up perfectly with the last strip under the windows.
The grasscloth is black , and my wallpaper primer is white . It’s common for teeny gaps to appear at the seams . In this case, it’s likely that white wall would peek out from those gaps. So I like to stripe under where the seams will fall with dark (diluted) paint . This takes measuring , plotting , and also a heat gun to get the paint to dry before the wallpaper hits it, to avoid staining. You can do a Search here to read more about this technique .
Now let’s talk about getting wallpaper in between those windows.
As you can see in the photo, if I hang a 30″ wide strip, a whole lot of paper is going to be cut off and thrown away. Also, a whole lot of sticky, pasted paper is going to bump against that window molding and maybe even the window glass. A lot to clean up! And unwieldy, to boot.
My solution was to stop the wallpaper just a little below the tops of the windows. Then I would patch in a 7″ wide strip in between the windows. This is trickier than it sounds, because, if it were a paper wallpaper, I could simply cut along a design motif and overlay the 7″ wide piece. But grasscloth is thick and overlaps don’t look good. Also grass has no design elements , and the reeds of grass don’t necessarily fall perfectly horizontal , and even if you cut everything perfectly true to square , if the window molding is a teeny bit off-plumb , then your edges won’t butt up perfectly.
So that’s a good reason for striping the black paint under where the butt join will occur.
Same thing for the sections under the windows. I measured and positioned the strips so that the top edge (which I had trimmed to be perfectly horizontal) fell between the narrowest part of the windowsill molding, for less visibility.
I admit, instead of butting the two pieces, here I did overlap the 7″ wide strip about 1/4″ onto the piece under the window, right at that narrow junction. It’s only about 3″ wide, and I figured no one is going to be examining it that closely, anyway. This saved me about a half an hour of measuring, trimming, testing, repeat, repeat.
This is my second window interlude, and by this time I had realized that it’s hard to trim stiff grasscloth around intricate moldings precisely . So I used paint to fill in the edges around the window molding, just in case there might be any gaps between the grasscloth and the molding, so you would see black instead of the white molding paint. I did this with a small sponge; if I had used an artist’s brush it would have been a bit neater and tighter to the conforms of the molding. But sometimes you’ve gotta relax and realize that no one’s going to be scrutinizing the insides of moldings below shin-level.
Area over windows finished, with drapes back in place.
Turns out this particular grasscloth is so uniform in color (quite unusual, I will add), that you can’t really see the panels , nor their equal widths , anyway. I’m still glad I took the time to do all this math and trimming.
Area below the windows, done. That last seam on the left bears some explanation, too. Moving across the top of the windows, I measured that that last strip – the full-length strip – would need to be exactly 35″ wide. It butted up nicely to the last strip above the windows.
But, due to twisting , shifting , expansion , unlevel and unplumb walls and ceilings , and other factors, there is a really good chance that that last 35″ wide strip would not butt up perfectly with the last 30″ wide strip under the window . So I planned to splice these last two strips together.
Yeah, the drapes are hanging there, I coulda overlapped the two strips about 1/2″ and the drapes would have covered it. With a thin wallpaper, I probably would have done this. But grasscloth is thick, and an overlap would be visible , and also the adhesive / paste can’t be trusted to adhere as well to grass as it would to paper .
So I plotted for a splice. Instead of trimming my last strip under the window to 30″ (read above), I trimmed it to 32″ wide. That way, when I hung the last full-length strip to the left, which was 35″ wide, it overlapped the piece under the window by a few inches. Then I did a double cut and spliced the two pieces. See below for details about that technique.
Grasscloth is 36″ wide, and this wall area is wider than that. So two strips were needed. This means you’re going to have a seam, and since grasscloth seams are always visible, it looks best to plot to have the seam fall down the center. It uses more wallpaper to do this, but it looks much better than having, for example, a 36″ wide strip next to an 8″ wide strip.
As mentioned above, in case you get thin gaps at the seams, a dark stripe of diluted craft paint under where the seam will fall, will prevent white wall from showing through.
Rounded / bull-nosed edges and corners have been popular in new construction for at least 10 years. I wish they’d go away. They’re very difficult to trim around, and hard for the paper to conform to and adhere to.
It’s very hard to trim around that rounded edge, because the paper is hanging over and blocking your view, because grasscloth is thick and stiff and your fingers can’t feel through it, and because the edges aren’t necessarily true and plumb so a laser level or other level won’t help you much.
I use this little gadget as a trim guide. It’s actually a small section of the same corner bead material that drywallers use when they assemble these walls. Cut to about 1″ long and notched in different places where you might trim along the edge of the wall.
It’s intended that you place your trimming knife in one of the notches and slide the gizmo along the edge and make your cut. I find that awkward and also inaccurate. So I prefer to use the notches as a guide and mark where I plan to trim with a pencil. Since this wallpaper is black, I used this marking pencil from my home sewing kit instead. Chalk might work, but I was afraid it might now wipe off completely.
The pink pencil line was barely visible, but it was enough for me to use a scissors to trim along the grasscloth. I like this better than using a razor blade as I can see better, and also less chance of scoring into the primer or wall. Which raises its own set of issues – do a search here to find previous posts.
Inside view of the trim guide.
Finished arch. Note the four panels of equal width above the arch. And two flanking full-height panels also the same widths.
I was lucky that there was no pattern to match, so I was able to butt my two flanking strips right up to the edge of the bull-nosed corner. No trimming needed! Then I measured the remaining width between these two strips (the area over the arch), divided by four, and cut four strips of equal widths.
I hung the two on the left, and then one on the far right. This left one strip still to be positioned to the right of center. So the pieces are going to meet over the arch, rather than the last strip falling in a corner.
Same as the last strip under the window (discussed above), it’s really difficult to get your last piece to fit in here perfectly. I’ve done it, but it takes a lot of measuring, trimming, testing, retrimming, and often starting all over again.
So I did a double-cut / splice.
A double cut involves cutting each strip an inch or so wider than it should be, and overlapping the two. Then you take a straight edge and sharp razor blade and cut through both layers. This handy tool is a wonderful non-slip guide for this process. It was invented by an installer colleague in the Wallcovering Installers Association ( WIA ) and she has them fabricated in various lengths (along with other cool tools ) and sells them on-line. Contact me if you’re interested.
Anyway, it takes a lot of strength to cut through two layers of grasscloth, so somewhat difficult for lil’ ol’ me.
You also want to be sure to not cut / score into the wall, because the tension of drying wallpaper can tug at the wall and cause it to actually come apart, leaving an open seam that’s difficult to repair.
So you’ve got to put some padding under the wall where the cut will take place. I use special strips of polystyrene (hard but flexible plastic) to pad the wall. Also invented by a colleague in the WIA , who also sells other cool tools and supplies. Contact me if you’re interested.
This black grasscloth was printed on a white substrate. If the seams aren’t absolutely tight, there can be worries about the backing showing through to the front. So sometimes we’ll take a piece of chalk or pastel (never oil pastel or permanent markers because they bleed and stain ) and run it along the edge of the paper – from the back, and taking care to not get chalk on the surface.
I do this frequently with dark papers ( do a search here to see previous posts ) but opted not to do it with this grasscloth. It wasn’t necessary, and might have stained the porous reeds of the grass. It was beneficial, though, to have striped dark paint on the wall under the seams, as mentioned above.
Ugh. Grasscloth comes 36″ wide, and this section of wall is 38″ wide. It’s not visually pleasing, nor is it easy from an installation point of view, to have a 36″ wide strip next to a 2″ wide strip. Or to use scraps and put a 25″ wide strip next to a 13″ wide strip.
So best to plan two strips of equal widths. Two strips, each 19″ wide, with the seam down the middle.
Actually, the strip on the left was 19″ wide, but I trimmed the strip on the right to 21″, because I like the wallpaper to extend 2″ over the top of the door molding. This provides a more stable surface in case of shifting foundation or walls, and less likelihood (knock on wood) of the seam opening up should the house / drywall experience shifting.
Note that design “rules” caution against seams down the middle of spaces. But it would have been more visually distracting (and used up more paper) to have made three strips of each 12.75″ wide. And would have looked even dumber to have used scraps left from other walls and put together two strips of disparate widths.
So the homeowner and I discussed during our initial consultation , and she was happy with the center seam. Once it was all finished, this particular grasscloth was so even in tone that you barely see the seams, anyway. Win-win!
This did use up additional paper, though, as noted in a previous photo above.

This is What You Get When You Ask the Painters to Wrap 1/4″ of Paint onto the Wall to Be Papered

March 22, 2022
A quarter inch of new pink paint from the sidewalls underlapping onto the wall where I will be hanging a mural will ensure that none of the original tan wall paint will peek out of the corner. All it takes is 1/4″ , which is what I asked the painters to provide.
As you can see, someone has a little problem with his measurements and math. This swath is more like 2″-4″.
Not a biggie. It’s a matt finish paint, and won’t be difficult for either my smoothing compound or wallpaper paste to adhere to.
My first task in this room is to skim-float the wall to smooth over the orange peel texture. That task took a lot longer than hanging the wallpaper!

The Big Easy On The Walls

March 5, 2022
West wall smoothed, primed, and ready for wallpaper.
The homeowner used to live in New Orleans, and she tells me that signs like this are very common in local convenience stores and neighborhood dives. Transplanted to Houston, these signs are very dear to her heart as a reminder of her roots – and the funky lifestyle in the Big Easy.
She wanted the signs recreated somehow to cover the walls in their newly-renovated powder room in the Houston Heights. I suggested she contact rebelwalls.com , who custom made the paper and sized it specifically to fit each wall in the room individually. I measured and made drawings, and a designer named Simon at RebelWalls laid it all out.
North wall before. This is the wall with the toilet and sink.
There were a couple of glitches, the first being that the strips were printed about 10″ longer than I requested. No biggie – I’d rather have too much paper than come up short.
But the main glitch being that I had asked for this “sign” to be centered over the toilet, which meant that the center of the sign (I used the middle fleur-de-lis) would land at 17.5″ from the wall to the left. But somehow it got printed to where the left edge of the pattern was 17.5″ from the wall … That left a whole lot of white space between the wall and the design, and also pushed the words too close to the mirror, which will hang over the sink to the right.
After careful measuring, calculating, and testing, I determined that if I used my straightedge and razor blade to take off a 12″ wide slice from the left side, the “sign” would move to the left such that its center would fall over the mid-point of the toilet.
VoilĂ ! As you see in the photo, now the words are nicely balanced on this section of wall, and will not crowd the mirror which will be hung to the right.
The rest of the wallpaper moving to the right is unprinted, so as to leave a blank slate for the mirror to hang on. Here you see that wall, and also the wall to its right. This east wall has the same sign, but in a smaller scale, sized to fit the narrower wall. It’s also placed at a different height
Graphic designer Simon used my drawings and measurements to get the words nicely centered on this wall. The area above the door to the right (not visible) is left blank.
Here is the west wall (on the right) abutting the south / window wall.
The bull-nosed / rounded edges / corners such as you see around the window are really a pain with wallpaper, especially when they go both around the sides and the top, and can lead to some impossibilities. Too complicated to get into here. But I was pleased with the way this worked out. And the placement of the pleated shades toward the front of the opening helped a lot, too.
One interesting thing to note is that the thickness of this non-woven wallcovering (along with the joint compound I used to smooth the textured wall) is enough that it narrows the space inside the window just a tad,,, and that makes it a bit tight for the shades to fit back in,,, and that opens the potential for abrading the wallpaper as the shade is raised and lowered over time.
Another point … even though the widths of the wall spaces to be covered were different, we requested that the size of the font on the “sign” lettering be the same on the west wall and the north / mirror wall, and ditto for the window wall and the door wall.
I also made sure that the “signs” started at the same distance from the ceiling. This then ensured that each “sign” would land at the same distance from the tile below it.
Synchronizing the size of the fonts as well as the spacing between ceiling and tile helps immensely to lend a feeling of unity and order to this room.
I spent a full 2 1/2 hours plotting, measuring, testing mock-ups, and going back to the drawing board, before I ever cut any paper.
Prior to that, there were two visits to the home to get measurements and kick around options with the homeowner. In addition, she spent countless communications with the manufacturer and with our specific designer.
All this futzing is important, because, with murals, there is no second chance. There’s only one of each panel, and if one gets screwed up, there are no more to pull off the bolt, like you’d have with regular rolled goods.
RebelWalls is the manufacturer. I’ve had lots of great installs with this company.
What was inside our box, including Simon’s dimensions and lay-out.
Basic installation instructions. Ours was a bit – a whole lot – more complicated, because it covered not one but four walls. In our case, it worked best to have each wall be a separate mural, so to speak.
RebelWalls includes free wallpaper paste. I prefer to use my own pre-mixed vinyl adhesive, which is SureStik Dynomite 780. Recently bought by Roman, so the name has changed to just 780.
Certain pastes have been known to ” stain ” non-woven wallpapers (areas look wet but never dry out). I think that a high moisture content in the paste has a lot to do with this. So I’m hesitant to use a powdered paste that needs to be mixed with water.
I’ll squirrel away that RebelWalls powdered paste for another, better suited job. For this home’s install, I’m sticking with my tried and true 780.
A coupla more notes.
One, this project was a study in vision, desire, anticipation, and patience. The homeowner first contacted me in July 2021. It took nearly eight months to come to fruition. Granted, they had a whole kitchen remodel in the middle, which also included an update to this powder room. But just speaking for the wallpaper, there were several site visits, many emails, and then innumerable communications with the design team at RW.
In fact, since I’ve hung lots of RebelWalls and am familiar with their process, I thought I could lay out the design. But this project of separate “sign” motifs for each wall section was taxing my skill set. Finally I laid down my pencil and paper and said, “Stop doing what you yell at your clients for doing, which is trying to do something you don’t have expertise in! RebelWalls has designers who are trained to figure all this out. So let THEM do the math and placement and calculating and layout.” So we turned it over to them, and within a short time they had it all worked out perfectly (except for those few glitches I mentioned). Their customer service was amazing.
All this was crucial to ensuring that mural pieces fit the wall perfectly and that the final product looks stunning.
I also want to mention that the RebelWalls quality is excellent. It’s a non-woven material which has many advantages (too numerous to go into here, but you can Search). The seams melt together like butter and are invisible – even on areas with all that bare white space with no pattern. On a simple accent wall, you can paste-the-wall to hang it. In this (and most) cases, I pasted-the-material, which gives more flexibility and also ensures that paste gets into hard-to-reach areas – like behind a toilet.
In addition, the non-woven material is designed to strip off the wall easily and in one piece when you redecorate.
The company offers scores of patterns, from cute to sophisticated, and, as we did this time around, can make custom creations.
Super customer service, too.

lottery , money order , checks cashed , household supplies

Koncentration Killer

April 23, 2021

I HATE noise. But this is probably the WORST type of noise EVER.

It’s uncanny how often these guys show up at the homes where I’m hanging wallpaper.

The racket and reverberation penetrate the walls and hijack my brain.

All this ruckus bollixes up concentration, focus, math, engineering … It leaves me with a headache, nausea, double vision,,,

“I Hate Leaf Blowers” – Google it.

Feathery Stripe in Memorial Area Entry Hall

February 1, 2020


I admit … When the homeowner first emailed her selection to me, I wasn’t crazy about the design. But once it started covering the first walls of the home’s entry – boy did I start to see her vision. It is stunning. And it’s one of those patterns that looks even better in person.

It’s a sort of a wide, scratchy stripe. The homeowner says it reminds her of feathers.

I spent a lot of time with math and engineering, and in the end was able to balance / center this pattern not just on the first wall with the front door (2nd photo), but on two other walls with doors, as well as this widest wall (1st photo). And I eliminated a noticeable kill point (no photo).

This wallpaper pattern “Plume” is by Cole & Son, and is on a non-woven backing. This means that it does not expand when wet with paste, plus there is no booking time, so you can paste it and hang right away – or you can paste the wall. I’m glad I pasted the material, because walls in this room were pretty wonky, and softening the paper by pasting it made it easier to manipulate it to match up with the crooked walls.

Non-wovens are also designed to strip off the wall easily, cleanly and in one piece when it’s time to redecorate.

I did encounter a few minor printing defects. But we had enough extra paper to work around them.

Balancing Grasscloth Panels

January 18, 2020


Because grasscloth does not have a pattern that can be matched, the seams are always visible. And, due to the characteristics of natural materials, the strips will have color variations within themselves. This means that you will distinctly see each individual panel on the wall.

Because each panel is noticeable, walls usually look better if each panel is the same width. In other words, on a wall 14′ wide, it looks better to have five strips that are each 33.5″ wide, rather than four strips that are 3′ wide and one that is 2.’

In addition, grasscloth invariably comes with edges that have been abraded during shipping. On top of that, it’s common to have color issues at the edges – either a light band, or a dark band, or irregular bands of shading along the edges.

For that reason, many paperhangers trim the edges off both sides of each strip of grasscloth. This allows the installer to trim the width to fit the wall’s dimensions, it gets rid of most of the damage caused by shipping and handling, and it reduces the shading that the manufacturer’s dye process may have left along the edges.

If you study the photo closely, you will see that all these panels are the same width.

And, while some jagged color variations do appear along some of the edges, it is not pronounced, as the darkest areas have been trimmed off.

There is still a color difference between the three strips on the right and the four strips on the left – but that is just the nature of grasscloth and its manufacturing process

As you can imagine, all this measuring and plotting and trimming takes extra time. If you’re like me and like math and geometry and logistics, hanging grasscloth can be a whole lot of fun!