Mural, mural on the wall

by carly_mchugh | 10 February 2024 5:20 pm

By Jay Kroll

On a Monday morning, you receive a call from a key contact at one of your bigger clients. They tell you about a side project they would like you to work on, which involves printing and installing a wall mural for the guest bathroom in their home. They have a great idea for how the print will work with their design scheme and provide a description that gets you just as excited as they are. This is someone you have worked with for years, whose information on every graphic or print job you have done for their office is spot on. While they offer you information on the dimensions and artwork, you start doing some basic calculations. They send you the artwork and confirm it is going to be applied to smooth, painted drywall. The paint is dry, and the walls are ready. Perfect. You prepare the image and load up a roll of your go-to standard wall vinyl, then you print it, trim it, and get ready for the job.

You agree to come by on Wednesday morning, and you are greeted at the door of their home and ushered towards the guest room off the entry. Even in the foyer, the first thing you notice is the smell of paint. Conversationally, you comment and ask, “This looks really nice. How long ago did you finish the remodel?”

They respond, “We just finished everything up last weekend and we’re excited to get the finishing touches in here once the mural is up.”

You try to stifle a sharp exhale, because you know dry paint is not the same as cured paint. You can already picture the vinyl bubbling within hours of installation, as the paint is still outgassing. However, you smile and walk on, already trying to figure out how you can postpone the job to give the paint more time. Then comes the room reveal, where you see the walls have an odd, bumpy, stucco texture. It looks a bit smooth, but it is definitely not a flat, sheetrock finish. You have your doubts about whether the film you selected is the right material, and now you have to figure out how to tell your client without adding tension to the situation—especially since you already have a printed and cut mural, representing a few hundred dollars in material and labour. How do you move forward?

Ultimately, the print service provider (PSP) community has some of the most tenacious, gifted problem solvers, who need to understand and juggle everything from colour management to carpentry, electrical engineering, and International Color Consortium (ICC) profiles, as well as have an expertise in all types of materials and substrates. Sometimes it is easy to rest on your experience or take someone else’s assessment or measurements at face value. However, for every graphic installation to be successful, it is important to remember the basics of film, adhesive, and liner, as well as the common wall surface types and how best to accommodate them.

Types of substrates

Smooth drywall

It is a common misconception that smooth drywall is perfectly smooth, as closer inspection reveals a series of gentle undulations in the surface, which is a bit of a challenge for adhesive films. By comparison, glass is typically perfectly smooth, with a hard finish ideal for adhesives of all types. Drywall/sheetrock has a natural fibre texture, morphing from its basic paper base when finished with a range of paint types, roller nap thicknesses, and specific materials. A uniform texture provides a consistent substrate for most adhesives, but this is where adhesive formulation and film selection are critical. A film that is too rigid with a thin adhesive layer, or a thin film with a glue that is too gentle or aggressive, will either fall off or pull paint when the time comes to remove the graphic. There is a delicate balance to keep when gauging factors such as tack, bond, and film type.

The paint sheen you use while administering the desired tone and feel for the space also imparts a surface variant into the mix when pairing it with an adhesive wall vinyl. Flat paint offers a low-sheen, non-reflective surface, but this comes at the cost of creating a low surface energy contact point for your adhesive. This micro-texture presents a challenge for adhesive bonding, which is exacerbated by the introduction of low and zero volatile organic compound (VOC) paints, which outgas their curing agents over a longer period of time. Flat paint requires an adhesive with higher initial tack, to allow the material to grip and hold as the bond grows over time.

Eggshell or semi-gloss paints inherently have a little more shine, and their smoother, harder finish makes for an ideal application surface for wall graphics. It is critical for clean removal to make sure the wall has been primed before painting, in a separate step. This seals the drywall paper and any loose particulate or joint compound, as well as creates a platform for optimal paint adhesion.

Stucco/textured walls

Stucco or textured walls introduce irregularities and require adhesive materials with extra conformability, which are designed to hold on intricate surface variations. A cast or ultra-conformable calendered vinyl is going to be best, but do not go running for your standard wrap material, as a slidable permanent adhesive might not be the best option. Stickers applied to these surfaces have to navigate their peaks and valleys, so these applications typically require something more high tack to stick and hold and be removed when you are ready.

Unsealed concrete/brick

With their coarse and porous texture, unsealed concrete and brick surfaces call for adhesives with heightened tack and cohesive strength. This is a different type of low surface energy wall, as it is living and breathing, with the potential for latent moisture in the substrate, along with uneven edges and a difficult environment for application. Both the film and adhesive formulations should accommodate any irregularities, ensuring consistent and durable graphic application across an unsealed texture. The best recommendation is to use a thick, high-tack adhesive on a dry day with a heated edge seal technique, or to attempt to seal the surface ahead of time to provide a moisture/debris barrier for improved adhesion.

Sealed concrete/cinder block

These surfaces essentially have their pores sealed—ideally with a semi-gloss or better paint—and provide a smoother, harder surface for applying graphics. Adhesives designed for these substrates still need to have high tack and strong bonding characteristics, and the films should have excellent flexibility and conformability to adhere to the variable surface.

Other/miscellaneous surfaces

The eclectic world of walls extends beyond traditional surfaces to include compositions such as synthetic materials, plywood barricades, and random surfaces—each with its own unique identity. On these walls, stickers encounter unconventional textures and really need to be tested in and for the end use. Adaptability becomes key for stickers to find their place on these experimental surfaces, but you have the opportunity to turn these substrates into unexpected canvases for creative expression.

Adjusting for environment

The materials we use can be partially standardized, incorporating what we know about films and adhesives to identify a few go-to solutions for these applications. Take our opening example: the walls have a texture to them, and we know our film, adhesive, or both will need to be able conform to the peaks and valleys of the wall. We can rule out most monomeric vinyl films, as they will not conform and stay put, and we should probably also avoid intermediate or blended films. Textured walls are best served with a full polymeric vinyl—either calendered or cast—as this will give the best conformability and flexibility, and the least amount of shrinkage of the available options.

Considering the potentially wet or steamy environment of a bathroom, it would be best to use a solvent-based adhesive versus a water-based acrylic adhesive for this project. The reason for this is the latter option uses water to deliver the glue to the liner in the coating process. If you have ever wet applied a clear decal to a window and noticed a chalky haze that dissipates after a while, it is because the vinyl you used incorporated a water-based adhesive. The hazy effect is caused by the water reacting with the adhesive. It can be temporary, such as on a window where the water is squeezed out and dried, but if it can creep behind the vinyl on a textured or porous surface, the water mix can compromise the adhesive bond. With a solvent-based adhesive, water was never part of the mix, and it will generally not be affected by contact with moisture. This does not mean the substrate is not impacted by the presence of water, such as with unsealed concrete and brick applications, but it would create a disruption between layers (adhesion) versus a breakdown of the adhesive layer (cohesion).

However, indoor smooth wall applications are just fine to use a monomeric or intermediate film and a water-based adhesive. Consider the initial tack of the adhesive being used, the immediate and long-term repositionability and removability, and even whether the vinyl can be reused in different locations, such as with some microsphere-beaded adhesives.

No matter the location of the project, surface preparation is key. Whether you are inside and need to make sure the paint is cured and clean, or outside where it may require pressure washing and a wire brush, it is critical to ensure your surface is free of loose debris, significant moisture, or contaminants such as grease or dust.

The way you install may vary, and it is important to test and practise with your chosen materials to hone your technique. Whether top to bottom or left to right, overlapping panels or butted together, you should explore both what the material is capable of and best suited for, as well as what you are most comfortable with for the types of jobs you choose to do.

Further, every manufacturer and material will have its own recommendations for application temperatures, cleaning and maintenance, durability, and removability. Their technical data sheets are your go-to location for details on the specific wall vinyl or fabric. When getting ready for a project, consider printing out a copy of the associated material documentation to go along with your job packet, and jot down helpful details such as the corresponding lot number, in case you need to refer back to it in the future. You can even create a site visit checklist, where the customer signs off on details such as the wall condition, paint age, temperature, and warranty. These specifics are not only helpful for ensuring a successful installation, but it is also nice to have the extra layer of documentation in the event something goes awry.

Knowing what to include

Speaking of warranties, your material warranty will also vary by manufacturer and may be tied to full or partial replacement of the rolls you use. While not typical, it could also cover additional elements such as ink, labour, shipping, or installation. However, what you decide to warranty or cover is important as well. Do you guarantee clean removal? If so, what does that mean? One major vinyl manufacturer has a “clean removal” tolerance which allows for up to five to 10 per cent of the adhesive to remain on the application surface. Do you warranty the condition of the underlying drywall or paint? Does your bid cover both installation and removal? Are any of these things contingent on your team doing the installation? All of these additions should also be factored into your price for the project, building in a little insurance, should any unexpected complications arise on the jobsite.

Knowing what to charge for any job is a guessing game of how much is too much and what is enough. It is not uncommon for a wall mural job to be 10 times the cost of materials and print. Therefore, a material and print cost of $1 per 0.1 m² (1 sf) for a 2.4- x 3-m (8- x 10-ft) wall would equate to an $800 job for print and installation with roughly $80 in costs. Time, travel, and installation will be factored in, but with a team of two and a well-prepared installation area, the job should take about 30 minutes from setup to completion. This is obviously a loose calculation, and the outcome will be different if the job is in a residential versus a commercial setting, or a retail or a multi-location repeating piece. Ultimately, you will need to determine what is best for your particular situation.

Conclusion

Based on all of this information, how would you respond to your key client in the opening illustration? Do you feel you would have a path for explaining the complexities and maybe some recommendations for materials to test on the wall (once the paint has cured)? How does this make you think about your current warranty? Does this pique your interest in pursuing future applications on complex varieties of walls or make you want to stay away? Do you think you can now spot the difference between a smooth wall and a rough wall, and deduce where to start on selecting the right materials?

The print industry is ever-changing with new materials, applications, substrates, and solutions. However, the constant in the midst of it is you, your relationship with your clients, and your particular expertise that keeps them coming back.  

Jay Kroll is a product manager at General Formulations, a manufacturer of pressure-sensitive solutions for the graphics industry. His focus is on cut vinyl, transit, and wall graphic applications. Kroll has been designing and developing various manufactured solutions for more than 20 years in the medical, aerospace, specialty tape, and graphics industries.

Source URL: https://www.signmedia.ca/mural-mural-on-the-wall/

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