Window Boards after plaster
In some scenarios, fitting the window boards after the plastering has been completed can be more beneficial to the overall finish of the job. As we’ve already looked at, window boards are typically installed before the walls are dabbed and plastered, with the plaster finish coming down onto the top of the board. For primed MDF window boards, this operation is practical and acceptable in terms of finish. However, for finished hardwood window boards, this practice can be harmful to the finished boards. Installing these finished components before the plaster can be detrimental to the overall outcome - risking damage to the boards. In these scenarios, we can fit the window boards after the plaster. By talking to the plasterers, we can end up with a window opening that is dabbed and plastered on all 4 sides, leaving us a smooth and clean finish at the correct height for the window board to be cut neatly into.
What is a joist?
What are the criteria for the installation of joists?
How are joists installed?
Installing window boards after the plastering has been completed is an easy process, and with a little care can result in a very clean and tidy finish. The process for both hardwood, plastic, and MDF window boards installed after plaster is as follows. The first step is to ensure that the surface of the plaster we’re going to sit the board onto is level to a comfortable tolerance of around 3mm. If it isn’t packing underneath may be required, though this will result in the front edge of the board possibly being caulked. As such, this process needs to be carried on from a decent plastering job. We also need to begin with an appropriate width of window board in relation to the depth of the reveal.
To measure and cut the board, we first need a measurement between the two outside corners of the window reveals. A very small tolerance of 1mm should be allowed here to allow for the board to actually fit into the opening. Take a note of this inside measurement. Next, we need to determine the length of our horns. 2” is common in most scenarios. From the end of our board, we can mark 2” for the horn, then our inside measurement, then another 2” for the horn on the other end of the window board. We can make a very faint line all the way across our board to mark where both of the horns are. We can then take an accurate measurement for the depth of the reveal at both sides of the window. These two measurements may not be exactly the same. In the locations on the board relative the position of the reveals, mark the distance in from the back edge of the board. Take these measurements across the length of the boards at the two end 2” horns. The final step to marking out is to take an exact angle from each side of the reveal off of the window frame. Translate this angle onto the board, registering off of the back edge until the bevel touches the inner corner of our layout, and trace this line. This is the line we will cut to, with the waste on the outside. After cutting out the waste and shaping the horns, if we were accurate enough, the board should fit snugly into place with no gaps along any edge. This operation is relatively delicate, as there is no room for error. That being said, the layout and cutting is not difficult, and is necessary for installing finished components.