My wife and I are trying to hang a mural in a long, narrow bathroom. After the mural has been up for something like 5 minutes, it started wrinkling. Trying to smooth it out, using a sponge, tore the paper and/or made it wrinkle worse. Did NOT size the wall first.
Needless to say, we stopped after the first couple of strips of the mural, trying to save as much as possible.
I would add that searching the web for help has produced conflicting instructions, like one place says size, not primer, another says primer, not size. Any help would REALLY be appreciated.

 

Who is the manufacturer of your mural?

A wallcovering primer should ALWAYS be used under wallpaper or murals, regardless of what the manufacturers says. Size is pretty much useless unless it goes over fresh plaster walls, which is the one exception the the rule above.

The wrinkles were probably caused by your smoothing technique. You should use a quality wallpaper smoother, you can buy one online here or pick one up at any paint/wallpaper/home improvement store. Using a sponge to smooth it only causes problems. Sand the edge to remove any manufacturing process excess on your new smoother.

I would speculate that you applied this over whatever paint was on the walls to begin with. The wallpaper paste that came with the mural then soaked into this porous surface. Now there is zero "slideability" between the mural and the wall. The lack of slip causes the mural to wrinkle during the drying process. Some parts shrink, some don't and this causes the wrinkles. Pushing and pulling after the fact only exacerbates the situation.

A primed wall would allow most of the paste to ride between the wall and the mural. This allows you to position the mural freely. If during the drying process, shrinkage occurs, the slip of the adhesive will pull the entire mural and no shrinking will occur.

If the wrinkles are acceptable, follow my instructions and hang the rest. If not, contact the manufacturer and get panels #1 and #2 (those numbers are for the sake of argument, but most manufacturers will ship single panels). Prime and hang the whole thing anew. Don't grab regular primer, make sure it says "wallcovering primer" on the can; there is a difference! Best of luck!

 

The wrinkles could be due to lack of soaking the paper prior to hanging..This is one of the most common errors..If the paste on the paper was not allowad to soak for at least 10 mins then no amount of smoothing will resolve the wrinkle problem.
As long as the walls have been prepped and sanded then a coat of size allowed to dry will adequatley seal the walls ready for wallpaper. (Sizing or not sizing the walls is not the issue with your paper wrinkling)
Of course..any stains on the walls should be blocked with a shellac based blocker before sizing the walls...Its just common sense really..

 

The manufacturer is Komar. The paper is not pre-pasted, and came with a small package of paste in the tube with the panels. I'll try the primer and see what happens. The reason the moderator's comments make sense to me is that the wall had wallpaper on it before we moved in, but it was removed by someone (not me). They then painted the wall, but not thick enough to cover the fabric pattern from the old wallpaper. Still looks like there is a layer of burlap on the wall. Thanks for the advice.

 

Here are some comments on a specific Komar mural from a fellow paperhanger:

JEERS:
- Like hanging wet tissue paper. Because of this tissue paper
characteristic each panel would rip at the slightest provocation,
making it nearly impossible to pick up paper by the corners.
-Equal expansion of panels was extremely difficult to obtain.
-Booking panels is ABSOLUTELY a NO NO. I tried and when I unbook
after less than a minute, the backing de-laminated.
-Colors from one panel to the next were not matched well.
-All trims needed to be done with a FRESH blade (#12 American Safety
Razor) changed every 40 inches or less.
-Trimming into textured ceiling was virtually impossible without
tears.(double entendre - rips and crying).
-All other trims were reasonably OK but with much pressure put on
trim
guide. An extremely shallow angle on the blade seemed to help.
-What few wrinkles there were did not dry out, but I suspect that was
due to hanging on plaster.

CHEERS:
-Being a leafy pattern all rips, tears, and delaminations were
easily painted.

COMMENTS:
-This mural is not impossible to hang.
-Two people would make it less frustrating so
that one could hold unhung part away from wall
while the other carefully laid it into position.
-The use of a foam sleeve on a roller is most helpful for smoothing.
-Paste each panel as quickly as possible so that soak time is
universal over the panel.
- I found that hanging top panel first was easier than the
recommended hanging the bottom first. Use strip of plastic wrap
under bottom edge to keep from adhering to
wall so that you can overlap it onto bottom panel.
-I think hanging on plaster with no inherent slip caused most
problems.
-I would like to try another one of these on a sealed wall and use
GH-14 or slightly thinned GH-34.
-I sincerely doubt this mural could be pulled through a
machine.
- Paste, relax, hang, and smooth all panels as consistently as
possible so that expansion is as uniform as possible.
-BE GENTLE.

If you need any of these comments explained drop me a line. Best of luck with your mural!