Installation instructions for Pro Cast Stone manufactured stone veneer

Pro Cast Stone Veneer can be installed over many types of substrates. Examples of this can be concrete or block. If it is installed over existing masonry, the existing surface must be clean and structurally solid. No wall ties, anchoring, lath, or scratch coat/back plastering is needed. Due to the lightweight advantage of Pro Cast Stone, no angle iron shelf or "brick ledge", shelf cast in the foundation, is needed.
If the installation surface is not of cement-type, such as OSB Sheathing, plywood, drywall, or a rigid insulation board product, you must "convert" it into a cement-type surface and provides the solid backing you need for installation.

When installing Pro Cast Stone Veneer over a non-cement type surface, you must install a moisture barrier. This will help you prevent the substrate from "drawing moisture" out of the mortar that will be applied before the installation of your Pro Cast Stone Veneer. This is done to protect the wall from absorbing any moisture, which could potentially damage and/or reduce the structural integrity of your substrate, and prevent the mortar from potentially curing too fast. It is recommended that you use 15 lb felt paper, tar paper, or Kraft paper. You should be able to fasten this with staples and a staple gun, or a hang held "tack hammer", in most cases. Tacking up your moisture barrier before doing anything else is an essential step in the overall installation process. Start at the bottom of the wall, or work area, and work your way upward. The entire work area must be covered with a moisture barrier. Take special care to overlap any seams, at least 4 inches, and make sure you overlap the lower areas with the upper. Now the water cannot get behind the moisture barrier if water were to run down the wall. Shingles use this same overlapping technique to keep your roof dry.

Next you need to anchor approved lath, flat, over the entire surface. This can be done with galvanized roofing nails or wide crown staples driven into the framing. These are only mechanical fasteners that will hold your manufactured stone veneer to the wall. It is important to understand that you should be generous with the amount of staples/nails you use; being sure you always drive the anchors into the framing to insure proper strength support. Install the lath similarly to how you installed the moisture barrier, by making sure all of your work area is covered in its entirety and being sure to overlap the seams at least 4 inches.

In order to complete your wall preparations for actual stone installation, you must now convert your non-cement type subsurface into a cement-type surface. You do this by applying a thin layer of mortar over your lath and moisture barrier. This thin layer should be approximately one half-inch thick and completely cover all exposed lath evenly at approximately one half-inch. You can spread the mortar onto the wall with any standard plastering or mason trowel. Ideally you want the mortar to be as flat as the surface will allow, while also applying it to your wall as fast as possible.
You can choose to scoop it directly from a bucket, wheelbarrow, or even a hand held hawk. Another popular choice is to place the mortar on a small piece of plywood and lay it right next to the wall. This will allow you to push the mortar directly up the wall, off the plywood, with your trowel. Once the mortar is applied to the wall, spread evenly at approximately one half-inch, and smoothed as flat as possible, you will want to "scratch" your mortar coat while it is still wet. Popular choices for this aspect of scratch coating are toothed/notched trowels or a course bristled hand held broom/brush. This is sometimes referred to as "furrowing" the mortar. Furrowing should be done from left to right and from right to left only, not up and down. This will increase the "bonding strength" potential for the mortar and stones. Once this is completed you should allow the scratch coat to completely set/dry (overnight is recommended, depending on climate, temperatures and direct sunlight).

Before you start installing the stone the next day, you will need to "wet: the wall. To do this you can use a sponge, a hose, or a spray bottle to dampen the wall surface. A dry wall can draw the moisture out of the fresh mortar fast, thus curing it too rapidly and weakening the bond between the fresh mortar on the stone and the scratch coat. This can be especially true in direct sunlight conditions or a hot summer day. Always take the time to dampen the wall before stick your stone. This does not mean turn on the hose and start drowning the wall. A simple misting of the dry mortar to moisten the work area is all you need. Too much water will leave your freshly installed stones sliding down your wall or not sticking at all. Over-watering can "loosen" your mortar, making it too soft to achieve a good adhesion. Use mortar that is too dry and your stones could "pop off the wall" easier then if you had moistened the wall before you started working.

Next, lay out a large number of stones as close to where you are working as possible, but minimize the risk of dropping excess mortar on them. Laying them on sheets of plywood is a simple solution and also allows you to choose the right size, shape and color of the next stone more efficiently. It also keeps your products clean and free from dust, dirt, and moisture from the ground. Pro Cast Stone veneer should always be kept as clean and as dry as possible before installation. Mortar does not bond well to dirty stones or wet stones. Keep the stones clean and dry. Any unused stones should be placed back in their box. Cover the box at the end of the day to maintain the best results/conditions the next working day.
Flats and Corners: Pro Cast Stone Veneer comes in 2 basic kinds of wall stones, consisting of your flats and your corners. Flats make up the majority of most walls. Corners make up the "border" or "outline" of the wall. All corners have right angles (90 degrees), two "stone surface" sides, and two "flat surface" sides. The flats are only flat on one side and stone surface on the other side. It is very easy to distinguish one from the other. Corners allow for fewer cutting options and can be more difficult to shape and "fill in your wall" with. Always begin by installing your corners first whenever possible. This will "outline" the area you are working with and allow you to "fill in the blanks" with your flat pieces.
Shaping and Fitting:
When you bring your fitting stones to the wall you want to always start from the top, then work your way down the wall to the bottom with your flat pieces and with your corner pieces. Install your corner pieces first, working from top down. Staring from the top will help you avoid, excess mortar that squeezes out, dropping on stones that may already have been stuck to the wall. As you work y our way down the corner, always alternate the longer and shorter ends of the corner stones as you go. When your corner is complete, you should be able to stand back and view each side of the corner you've just worked on. Regardless of which side you are viewing, you should see an alternating pattern of long side, short side, long side and then a short side. Alternating in this manner will help you "break up" any unwanted patterns and blend your corner naturally into the rest of your wall. You should also take care to alternate sizes, help give your wall the natural look and variety you intended to have.
Cutting or shaping the stones so that they fir properly and blend well with the neighboring stones is very important. When "fitting" stones to the wall, simply hole the stone up to the place on the wall you would like to install it. Use a pencil to mark the stone where it is to be cut or chipped off. Once marked you can use a masons trowel to gently chip and shape the stone to fit by striking the stone with the edge of the trowel. You can use this same technique with the masonry hammer. Be dire to support the stone when you are striking it to prevent from cracking or breaking in the wrong place. Another, more precise option, is to use a 4 inch hand held grinder with a diamond cutting wheel. This will provide fast and clean cuts. Wearing a dust mask is suggested if using a grinder, due to excess dust that is created from the cutting wheel.

Now that we are ready to stick the stone to the wall we need some fresh mortar to spread on the backs of stones (also known as "buttering" the stone). You can use the very same mortar to stick the stones as you used to apply the scratch coat to the wall. The "buttering" mortar should be thick and wet when being used to install your stones. Mortar mix that is too wet will not adhere the stone properly to the wall and will likely result in your stone falling off or sliding down the wall. Mortar that is too thick and dry will usually result in the stones falling off the wall before they achieve a satisfactory bond.
Completely cover the back of your stone with fresh mortar before trying to adhere it to the wall. Generally speaking, a 3/8 to 5/8 inch thick layer of mortar, "buttered" to the back of your stone, will be enough to achieve a successful bond. Less than this amount could mean the stone does not achieve a strong enough bond and, likewise, too much mortar could result in the same weak bond (too much mortar usually makes the stone too heavy to support themselves). Too much weighted often sited as a reason "extra" mortar can result in less then perfect results. Experience will allow you to more accurately gauge the appropriate amount of mortar to butter your stone with. Just a few installed stones should be all this is needed to get you on the right track to buttering your stones with the appropriate amount of mortar. Once the back of the stone is buttered you can run a ½ inch high ridge around the rim of the back of the stone. The extra mud around the back rim of the stone will squeeze out from behind your rock and aid in filling in your mortar joint as you slide the stone into place. While some stone patterns have large mortar joints, others have smaller joints. A smaller mortar joint requires less mortar around the rim to squeeze out and less mortar to finish filling the joint. A larger mortar joint, overall, will require more mortar around the rim and more to finish filling the joint.
Be mindful of squeezing out too much mortar from behind your stone by either applying too much mortar to the stone or by pressing the stone too firmly onto the wall surface. Squeezing too much excess mortar out can also leave too little mortar between the stone and the wall to maintain a good bond. The excess mortar could also get on the face of the stones and that means more clean-up duty for you. Sometimes, less is more.

Now our wall has a moisture barrier. The moisture barrier is completely covered by lath and out lath is completely covered by our scratch coat. Our non- cement-type surface is now a cement-type surface. Next, you need to begin covering the scratch coat with the stones you've selected. Hold the stone approximately 1-3 inches off the wall and about an inch or two below, above, or off to the side of its final placement on the wall. If you are satisfied with the color, size, shape and butter layer, go ahead and press the stone firmly too the wall as you slide it into its intended position, slightly wiggling it as you push it into place. This action helps spread the mortar evenly across the back of the stone and allows for some excess mortar to squeeze out from behind the stone and into the mortar joint bed. The stone is now installed and should not be disturbed for at least 24 hours. Some masons even give the stone a firm tap with a small rubber mallet after they slide it into place. We recommend using this technique for improved bonding results. Once the stone had been set into place and the mortar begins hardening/setting up, again, DO NOT disturb the stone. The mortar will grow weaker before it growers stronger. Prematurely disturbing the stone could result in the stone falling off the wall.

The stones are on the wall now and have been undisturbed for 24 hours. It's time to start filling in the joints between the stone. You can do this with a grouting bag or just fill in the joints by hand. Using the grouting bag will save time, create less mess, and result in less mortar dropping on the faces of the already installed stones. It is important to keep the stone clean and free of mortar stains for a quality and professional looking result when your project is completed. To use the grouting bad, which just looks like a bakers pastry bag, you simply fill the bag with mortar and close up the larger opening by twisting the bag until mortar starts to ooze out of the smaller opening. As you twist the grouting bag harder the mortar will squeeze out of the tip and lay a bead of mortar between the stones for you. Simply place the tip between the stones and insert it deep enough to touch the wall that is still exposed between the stones. Once the tip is resting against the wall you can begin twisting your grout bag and forcing mortar out of the applicator tip. As the joint fills up to the desired depth you can move your grouting bag along the joints as you fill them in. be sure to fill the joint as evenly as possible as you go. Once the joints are grouted in, you need to give the mortar a short time to start setting up. The mortar will need to dry up a big before you "strike off" the joints and brush them out. Depending on the temperature, climate, sunlight and air moisture this dry time will vary.
If it's still wet the mortar will be too soft to strike off the joints and smear instead. This can often result in a messy wall. To test this, use a striking tool, your finger, or a piece of wire you can twist a loop into (the loop should be about the size of your finger tip). You "rake" the joint by laying the tools/finger/loop in the joint and pressing firmly as you slide the tool back and forth thru the joint. If the mud starts oozing and smearing it's better to wait for a stronger and dryer "set" on the mortar. If the mortar "packs down" and seem to be partially dry when you begin striking them off, you should be fine. The joint should feel firm and have only a little "give" to it when you are pressing the tool and dragging it thru the joints.

Continue doing this until they are "raked" to the desired depth.
Once the joints are raked, it's time to clean them.
Take a medium bristled brush and begin brushing the joints. Clear any excess mortar off the joints edge and smooth out the "bed" of the joint. Be sure NOT to brush all excess mortar off of the edges and face of the stones until the mortar is partially dry. Also, do not let the mortar COMPLETELY "set up" on the face of your stones. It is better to wait until the mortar is partially dry, so do NOT attempt to clean wet or soft mortar off your stones either. Allow it to dry slightly before cleaning. Wet mortar droppings on the faces of the stones can result in permanent staining and take away from the natural beauty of your Pro Cast Stone Veneer. The "set-up" time for the mortar will vary depending on climate, temperature, and direct sunlight. Check on mortar joints every 5 to 20 minutes, depending on your weather conditions, to see if they are ready.

Now that all these steps are complete you should have a finished wall and can begin cleaning up your workspace. Following these steps should give you, not only, a professional looking result but also a quality result.