diff --git a/applications/solvers/heatTransfer/chtMultiRegionFoam/chtMultiRegionSimpleFoam/solid/solveSolid.H b/applications/solvers/heatTransfer/chtMultiRegionFoam/chtMultiRegionSimpleFoam/solid/solveSolid.H
index ca29fcd0d9..c480614510 100644
--- a/applications/solvers/heatTransfer/chtMultiRegionFoam/chtMultiRegionSimpleFoam/solid/solveSolid.H
+++ b/applications/solvers/heatTransfer/chtMultiRegionFoam/chtMultiRegionSimpleFoam/solid/solveSolid.H
@@ -3,9 +3,11 @@
     {
         fvScalarMatrix hEqn
         (
-            thermo.isotropic()
-            ? -fvm::laplacian(betav*thermo.alpha(), h, "laplacian(alpha,h)")
-            : -fvm::laplacian(betav*tAnialpha(), h, "laplacian(alpha,h)")
+            (
+                thermo.isotropic()
+                ? -fvm::laplacian(betav*thermo.alpha(), h, "laplacian(alpha,h)")
+                : -fvm::laplacian(betav*tAnialpha(), h, "laplacian(alpha,h)")
+            )
           ==
             fvOptions(rho, h)
         );