Embedding Sign Letters in Concrete
This article attempts to address the considerations required for those do it yourself sign installers that wish to embed metal sign letters, numbers and logos into wet concrete or cement. it should not be construed as the only methods or the preferred methods, since various sign installers and general contractors that have done this sort of work, will have their own preferred method. We are by no means experts, and this article should not be read as conveying expert opinion. One thing for certain is that embedding metal sign letters into concrete requires a bit more consideration.
INSIDE OR OUTSIDE?
Where the letters will be installed is of great importance. For inside applications on floors, you have to carefully consider the amount and type of foot traffic. Why the type? If the letters are placed near an entrance way then it is likely the letters will be exposed to more abrasive foot traffic and even dampness. This can quickly remove any protective coatings and the materials themselves will be subject to oxidation. In the case of Bronze sign letters and Brass Sign Letters, two of the most popular metal letters used in this sort of application, the letters will soon pit and turn green or black as oxidation takes effect. Any satin finishes, which are usually applied by sanding the metal letters at the factory, will soon wear down. Stainless steel sign letters may be a better choice in these areas. If the embedded metal letters are placed away from entrance ways, the next consideration is scuffing and janitorial wear. Large floor polishing machines will quickly wear down material, but in the case of polished letters, will very likely help to keep the letters bright.
Outside use presents its own problems entirely. Ground heave, expansion, contraction, cracks, weathering, oxidation, grit from tires and shoes, all contribute to a maintenance nightmare. We have supplied replacement bronze letters and numbers twice now to the Four Seasons Hotel & Resort in the West Indies., for use poolside. Here we have multiple issues, salt, pool chemicals, electrolysis, scuffing, cracking, heave, contraction, expansion. Even 2 coats of heavy outdoor clear coat was soon worn away. Pitting and corrosion in the form of a black patina, soon set in.
Polished bronze with no maintenence soon turn black! Maintenence is essential ! Clear coats will never protect against this sort of installation.
These bronze letters were originally polished and had stud mounts welded to the back of the letters which were embedded into the concrete. Even so it didn't stop the letters from being removed or broken. Embedding stud mounted letters into the concrete does definitely help to maintain stability. Without the studs penetrating the concrete, the letters would soon come loose and disappear.
A better way, although far more costly, would be to embed the letters using a stabilizer plate (above). For outdoor applications, stainless steel would be the material of choice. For indoors, an aluminum plate could be used. Recessing metal letters, ever so slightly below floor level may help to alleviate wear from foot traffic.
This kind of installation is best left to professionals. However, if you choose to do it yourself, at very least you will need letters with stud type mounts attached to the back. Polished letters would be best since you can always with regular maintenance and a lot of elbow grease, maintain the shine by hand polishing. A clear coat preservative does help initially, but it will soon require re-coating.
Another trick for inside use would be to recess the letters about 1/16" to 1/8" and then after final installation, pour a clear hard industrial resin over the letters to form a wear barrier. This is the same sort of resin many older folks might be familiar with in nightclubs and bars back in the 60's and 70's, where resin was poured on bar tops with photos, beer mats and other items encased in the resin.