Is Drywall A Suitable Substrate for Stone Veneer?
Most people, the author included, that have ever swung a hammer in the name of home improvement have experienced the temptation to want to cut a corner every now and again. Maybe it’s something as simple as working with your thinset to lay stone or tile right after you get done mixing it instead of letting it set for a few minutes, or possibly even something with a greater risk for danger, like changing out a light fixture but only turning the power off at the switch and not the breaker. Working with stone veneer products, especially the ones that get used on a lot of renovations and remodel projects, we hear from customers frequently about cutting one corner in particular on the installation – whether or not the product can be installed over drywall.
First and foremost, the answer to that question is no, without any exceptions or conditions. There are a number of suitable substrates for installing stone veneer, all of which are cementious based, such as cement board, brick, block, or a wooden substrate that has been prepared with a metal lath and masonry scratch coat. Now that we got that out of the way, let’s take a look at why drywall isn’t a suitable substrate for stone veneer.
Weight is the primary reason that drywall does not make a suitable substrate for a stone veneer installation. Our stone veneers can weigh anywhere from about 7 to 13 lbs per square foot. If you take a few minutes to study the composition of drywall, you’ll find a pretty basic product – essentially its gypsum between two heavy pieces of paper. Drywall is a perfect product for interior walls and ceilings as its relatively lightweight, easy to install and work with, and can accept a variety of textures, paints, and lightweight veneer applications such as wall paper. However, the physics don’t work when you start to think about hanging a heavy stone tile or panel that’s being bonded to the outer paper layer of the drywall with a wet cement based thinset setting material. Not only is the paper layer not designed to hold that weight up, the moisture in the thinset is going to start off by compromising the integrity of that paper layer right from the start.
We get the question so frequently about installing our stone veneer products over drywall because of its prevalence in the building industry and also that many of the products that our product is ideally suited for are likely going to have existing drywall already in place as the wall system. Back splashes and fireplaces are great examples of this. Both are fantastic applications for stone veneer, but if the space is being remodeled, or even in the case of most new construction projects, drywall will likely be what’s currently in place because it’s inexpensive, easy, and prevalent in all other areas of the house.
Fear not if the drywall has got your DIY stone veneer project at a standstill! Beyond the obvious solution of ripping out the existing drywall, getting back to the studs or furring strips, and rebuilding the wall for your stone veneer using cement board, there is another alternative. Many of our customers end up leaving the drywall in place and simply covering it with .25” thick cement board. The thinner cement board will have plenty of structural rigidity for most stone veneer projects seeing as though its gaining flexural strength from the existing drywall behind it. Probably the most important part of a cover up installation like this is to make sure that you’re using screws that are long enough to go through both your cement board, existing drywall and still sink at least half way into your studs.
Thanks for taking a few minutes to learn why installing stone veneer over drywall is not a good idea. We have a great team of knowledgeable reps with industry experience that are ready and willing to answer your stone veneer installation questions, so don’t hesitate to contact Norstone today to learn more and get your hard to answer questions answered.