diff --git a/src/ifcopenshell-python/docs/ifcopenshell/installation.rst b/src/ifcopenshell-python/docs/ifcopenshell/installation.rst
index 99816bda1a..0cd7a39d20 100644
--- a/src/ifcopenshell-python/docs/ifcopenshell/installation.rst
+++ b/src/ifcopenshell-python/docs/ifcopenshell/installation.rst
@@ -62,6 +62,8 @@ operating systems. GCC (4.7 or newer) or Clang (any version) is required.
 
        sudo apt-get install git cmake gcc g++ libboost-all-dev libcgal-dev
 
+   The CGAL version that ships with Ubuntu 20.04 is too old. Users on Ubuntu 20.04 are advised to manually install CGAL 5.3.
+
 3. Install OpenCascade Technology (OCCT).
 
    .. code-block:: bash
@@ -73,6 +75,8 @@ operating systems. GCC (4.7 or newer) or Clang (any version) is required.
         If OCCT is not available, an alternative is to `manually compile OCCT
         <https://dev.opencascade.org/release>`__.
 
+   IfcOpenShell 0.8 depends on fairly recent OCCT additions such as the BVH Tree functionality. Users on Ubuntu 20.04 are advised to manually compile and install OCCT 7.7.
+
    Another alternative is to use OpenCascade Community Edition (OCE), but it may
    lag behind OCCT and is no longer actively maintained so is not recommended.
 
@@ -137,24 +141,26 @@ operating systems. GCC (4.7 or newer) or Clang (any version) is required.
         # Check all paths are valid for your environment
         cmake ../cmake \
               -DOCC_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu/ \
-              -DOCC_INCLUDE_DIR=/usr/include/ \
-
+              -DOCC_INCLUDE_DIR=/usr/include/opencascade \
+              \
               # Optional Collada support
               -DCOLLADA_SUPPORT=On \
               -DOPENCOLLADA_INCLUDE_DIR="/usr/local/include/opencollada" \
               -DOPENCOLLADA_LIBRARY_DIR="/usr/local/lib/opencollada"  \
               -DPCRE_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu/ \
-
+              \
               # Optional HDF5 support
               -DHDF5_SUPPORT=On \
               -DHDF5_LIBRARIES="/usr/local/hdf5/lib/libhdf5_cpp.so;/usr/local/hdf5/lib/libhdf5.so;/usr/lib64/libz.so;/usr/lib64/libsz.so;/usr/lib64/libaec.so" \
               -DHDF5_INCLUDE_DIR="/usr/local/hdf5/include" \
-
+              \
               -DCGAL_INCLUDE_DIR=/usr/include \
               -DGMP_INCLUDE_DIR=/usr/include \
               -DMPFR_INCLUDE_DIR=/usr/include \
               -DGMP_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu \
-              -DMPFR_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu
+              -DMPFR_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu \
+              -DJSON_INCLUDE_DIR=/usr/include \
+              -DEIGEN_DIR=/usr/include/eigen3
         # Replace X with number of CPU cores + 1
         make -j X
         # Optionally install to the system