Chimney-Chase Upgrade

Easy-to-install faux stone looks like the real thing (without all the expense and effort)

Stone façades have become increasingly popular during the past few years. The warmth and beauty of stone always turns heads, but the material — and the mason required to install it — can be very expensive. And a DIY masonry project involving costly stone can go awry if you don’t know exactly what you’re doing.

That’s why we were ecstatic to find an easy-to-work-with faux stone called BellaStone. Unlike other faux-stone products, this one not only looks like real stone but also feels like it. That’s because the makers of BellaStone thermally infuse real stone aggregate and natural pigments into the polymer during the manufacturing process. Best of all, this is a DIY product that’s easier to install than vinyl siding. Read on and I’ll walk you through the installation of BellaStone on a chimney chase so you can see how easy it is to enhance your home with the look of stone at a fraction of the cost.

Step 1: Demo the old siding
For this project, we removed all of the old siding on the chimney chase and checked the sheathing and framing for decay. Unfortunately, we found more than we bargained for. Large sections of sheathing had completely rotted away; some areas of the chase even contained wasps and ant colonies. After two days of demolition and pest removal, we fixed the chase frame and added new sheathing as needed.

Be sure to check for rot and insects before you apply new siding. In this project the existing sheathing had rotted and had to be replaced.

This step is very important in any exterior-cladding application. Never try to apply siding over dry rot and decay; the siding will eventually pull away from the subsurface, allowing more water intrusion and further damage to the structure.

Step 2: Install house wrap and corner flashing
This is another step you do not want skip. The house wrap protects the new framing and sheathing from future moisture intrusion and decay. The metal flashing adds an even higher level of protection where the stone corners meet. The manufacturer of BellaStone recommends installing at least 10 in. of flashing on both sides of the corners. We attached the corner flashing with galvanized fasteners every 8 to 12 in. Then we sealed the flashing edges and house-wrap seams with house-wrap tape.

Apply house wrap and corner flashing before installing the BellaStone panels.

Step 3: Lay out the BellaStone and install starter strips
In this project, we installed BellaStone Quoin Corners along the outside corners of the chimney chase. These stone corners match the BellaStone panels and overlap the panel edges. To accommodate the corners, we snapped chalk lines 7-1/4 in. from the outside edges of the chimney chase. Next, we snapped level lines horizontally at the base of the chase 2-1/8 in. from the bottom edge of the sheathing and installed the BellaStone metal starter strip. Once all vertical and horizontal lines were laid out and the starter strip was in place, we were ready to install the panels.

Step 4: Measure and cut the panels
BellaStone panels are designed to be installed from left to right; the left side of the stone panel overlaps the right flange. Cut edges are placed toward the ends (or terminations) of a row, never in the middle of a row. The width of this chimney chase required one full panel and two smaller cut panels at either end. Like any siding application, it is best to stagger seams from row to row. BellaStone recommends staggering seams at least 6-1/4 in.

Place the BellaStone panels stone-side down for measuring, marking and cutting.

To cut a panel, we placed it stone-side down on saw horses and scribed a mark using a framing square. Then we cut on the mark with a circular saw equipped with a carbide-tip blade.

To stagger joints, we varied the length of the partial panels to the left and right of the full panel. This approach was fairly simple, although a few times we accidentally measured from the wrong side of the panel and had to use those miscut pieces in future rows. But because the chimney chase was more than two stories high, we had plenty of chances to make up for our mistakes and had very little waste at the end of the project.

Step 5: Fasten the panels to the sheathing
We installed the panels by first fitting them into the starter strips and then fastening them to the sheathing with 2-1/2-in. corrosion-resistant screws inserted through the metal clips and machined slots in the panels. We left a little bit of room between the panels and the sheathing to allow for expansion and contraction in varying temperatures. Fastening the panels too tightly against the sheathing also makes it difficult to install the next row.

Install the BellaStone panels using 2-1/2-in. corrosion-resistant screws and metal clips provided by the manufacturer.

We continued to install the panels, staggering each row and leveling every other row until we reached the top of the chimney chase. Then we started up the sides, again running the short panels to the snapped line at 7-1/4 in. from the corner of the chase. We cut the short panels on both ends to fit against the inside corner of the house and to terminate at the outside corners.

Step 6: Install the BellaStone Quoin Corners
Once all of the panels were installed, we started on the corners. The BellaStone Quoin Corners come in 12-in. and 24-in. lengths. To stagger the corner and panel joints, on the first row we inserted a 12-in. quoin corner into the starter strip and fastened it to the sheathing exactly like the panels; then we installed 24-in. corners at each subsequent row, working up the chimney chase to the top. At the top of the chimney, we cut the top edge of the corners to match the flush top of the chase.

After installing the panels, attach the BellaStone Quoin Corners along the outside corners of the chimney chase.

Step 7: Caulk the seams and apply stone dust
When the panels and corners were in place, we caulked all joints and seams with a color that matched the stone. Then, before the caulk set up, we used a small brush to embed color-matching stone dust (supplied by the manufacturer) into the caulked joints. This extra step was time-consuming and monotonous, but the finished effect was well worth the effort. Once the caulk and dust were applied, it was very difficult to distinguish where the individual panels started and stopped. Even from a few feet away, the chase looked like it was made with actual stone. And it was achieved without the high cost and special skills required to install the real thing.

Caulk all joints and seams to prevent water intrusion; then apply stone dust to the caulk with a small brush.