If a cast is severely damaged due to fire or water damage, a more serious repair may be needed. In the majority of cases like this, some of the original cornice will still be okay so it can be repaired instead of being replaced. Like all repairs, it must it must match what is already there. A good repair will never be noticed.
There are 4 methods to be able to make a new length of cornice.
First method
For the first method, a piece of the original cornice can carefully be removed ready to be moved to the workshop. Record a measurement of the length and width of the cornice and take a photo too. Make a note of the amount of cornice you will need to replace the damaged part.
You will need to make the end of the cornice that you have removed perfectly square, draw a ceiling and wall line on a piece of paper at a 90 degree angle to each other and place the cornice onto the paper. Make sure you mark what is the ceiling line and what is the wall line then draw around the cornice. Extend the ceiling and wall lines on the drawings and draw in the bench line. This will then give you the template so you know where to file.
Second method
The second method is an easier way of getting the profile outline if you cannot remove the damaged area of the cast. All you have to do is find a section of cornice above a door or somewhere that will not really be noticed. Using a fine-tooth saw, make a cut in the cornice making sure it is wide enough to fit a piece of stiff card in and slide the card in.
Then you will need to draw the outline of the cornice onto the card with a pencil and then cut out the outline. Square off the end of the cornice on the drawing. Draw a ceiling and wall line onto paper, marking which line is the wall and which is the ceiling. Make the ceiling and wall lines longer and draw in the bench line so that you have the template so you know what needs to be filed.
Method three
Method three is best used if it is not possible to remove a section of the cornice or if you can not make a cut with a fine-tooth saw. To use this method, you will need another pair of hands to help. You will need to roughly draw the shape of the cornice on to a piece of paper. Holding the level vertical making sure the end is touching the ceiling, measure from the level to the moulding outline.
Make sure you write down the measurements on to the drawing. Do the same again but hold the level horizontally making sure one end is on the wall. You should then cut out the cornice drawing and hold it up to the original, making sure that they are the same. On the drawing, extend the ceiling and wall lines.This will give you the template so that again you know where to file.
Method four
For method four, the last method, you will need to get in touch with the client to explain to them that a cast needs to be taken of the original cornice and telling them what you intend to do with it. The client has to be in agreement for you to be able to do this. This method is suitable for plain cornice only.
You will first need to find a piece of plain, undamaged cornice. Three coats of shellac should then applied 150 mm wide on the section you have chosen to use and then it can be greased. A cast should then be taken of the area you have used shellac and grease on. Once the plaster in the cast you have made has set, it can then be removed and one edge should be squared off. You will then easily be able to get your template from this so you know where needs to be filed.