Step Light Trough U-Shape Bulkhead

Required tools:

  1. Pencil
  2. Measuring tape
  3. Mitre Box
  4. A very fine saw
  5. Chalk line and chalk
  6. Ladder
  7. Adhesive
  8. Paint scraper / filling knife
  1. Caulking gun for applying adhesive if adhesive is in a cartridge
  2. Drop sheets if installing cornice in a room where tiles or carpets are already installed.
  3. Sponge or mutton cloth for wiping away excess adhesive.
  4. Very fine sandpaper

Cutting cornices is a skill that requires a bit of practice. If you are a novice then it is recommended to buy an extra length or two of cornice to practice on.

Assembly of the Bulkheads:

  • Slide the Upright Profiles horizontally as indicated in the images below.

Note: Don’t use too much force, and gently guide the Upright Profile into the Bottom Profile.

Step Light Trough U-Shape



  • Measure the outside linear meters of the bulkhead layout of the walls / ceiling to which the bulkheads must be installed. (Add 5% to 10% for waste.)
  • Ensure that the surface of the walls and ceilings, to which the bulkheads will be installed to, are free from dust and dirt and is completely dry.

Tip: You may use a 120 grid or finer sand paper to ensure the installation area is clean but make sure that all dust from sanding is wiped clean with a clean dry cloth.


Familiarise yourself with the bulkhead size. In the diagram below, you will see two measurements:

  1. Width – The width of the bulkhead
  2. Drop – The distance from the ceiling surface to the bottom edge of the bulkhead


For U-Shape Bulkheads

  • Determine how far the bulkhead must be installed away from each wall in the room and mark the installation line parallel to each wall.
  • Use a chalk line to mark the outside perimeter of the bulkhead using the measurement points as a guideline. Allow chalk line lines to cross each other at intersections.
  • To mark the inside perimeter installation line (if required), measure the width of the bulkhead from each corner intersection and make a mark.
  • Then use a chalk line to connect all the marks and you should be left with all the required guidelines as per the diagram below.


  • Always start the installation at the most visible corner in relation to the entrance to the room.
  • Below is a diagram that indicates which corner will be the most visible. The reason for this is to minimise any joints in line of sight.
  • Always start with the longest lengths first to minimise waste.



Note: To make a 90 degree joint it is required to cut the butt end of the bulkhead at a 45-degree angle. The trick to successful mitres is to ensure that the bulkhead is cut correctly. Either with a mitre box, or by using guidelines marked out and cut with a utility knife or fine tooth saw.

The bulkhead uprights (Profile B, C, D, and E) are placed in the mitre box that has a horizontal 45-degree angle.

Alternatively, mark the angle required on the bulkhead profiles, and cut slowly, using a utility knife or fine tooth saw.

Note: To make sure the angle is cut correctly, ensure that the shadow line is always on the outside of the bulkhead.

  • Lay the Profile (B, C, D and E) flat in the mitre box with the shadow line facing up. Use the 45-degree angle in the mitre box to cut the corners.
  • Cut one corner on the left-hand side of the Profile. On another Profile, cut one corner on the right-hand side.

These should form an inside corner, as shown in the Image.

  • Lay the Profile (B, C, D and E) flat in the mitre box with the shadow line facing down. Use the 45-degree angle in the mitre box to cut the corners.
  • Cut one corner on the left-hand side of the Profile. On another Profile, cut one corner on the right-hand side.

These should form an outside corner as shown in the Image.


Apply a bead of adhesive along the top edges of the bulkheads (as indicated in the diagram), as well as the butt end (if being glued to another bulkhead or wall).

Note: Don’t be frightened of putting on too much adhesive, you will be able to scrape it off easily using the filling knife and a wet cloth or sponge to clean the wall or ceiling. You want it to just be squeezing out from the edges as you press the bulkhead into position. Be careful not to squeeze out all the adhesive as the adhesive will lose its ability to bond and cure.

  • Align the bulkhead to the chalk line on the wall to ensure a consistent straight installation. If you are installing from a corner, then leave just a few mm’s from the wall to allow the other mitre end to fit with the adhesive applied.
  • Once the first bulkhead length is installed then apply adhesive to the next length including the mitre joint or butt end that is joined with the first length. Pins can be used to keep joints in place.
  • Use your filling knife to press adhesive into any gaps, pushing adhesive into any joints that do not quite meet and any undulations in the surface of the wall or ceiling.


Once the installation is complete allow 48 to 72 hours for the adhesive to cure.


Prior to applying the desired color, it is essential to first coat all LED Ready products with a layer of grey paint. This initial step is crucial as the grey paint serves to effectively block any light from penetrating through.

Before painting, inspect all the joints and sand away any excess adhesive or fill exposed joints. You can use the polystyrene adhesive to fill the joints or alternatively any acrylic filler. Be sure to leave a bit of excess over the joints which should be sanded smooth after 24 hours.

NOTE: Only use acrylic paints when painting polystyrene bulkheads.