How to Fit a Floor Grille
Adding Ventilation to Floors
Ventilation is essential in any floor space. Stagnant air can lead to rot, unpleasant smells and damp, which can destroy floor finishes and carpets, and in some cases the floor itself, if left untreated. Some floors suffer from a lack of ventilation more than others, such as those in bathrooms and kitchens. Before starting on major work it is worth checking that poor ventilation is not simply a case of existing air bricks being blocked by soil and dirt.
Fitting a Floor Grille
Though not as effective as an exterior air brick, a grille fitted into floorboards will allow air to circulate in the floor space, which might otherwise be a potential breeding ground for rot and infestation. If the grille is installed under a window or a radiator then the convection currents will help to draw air into the room.
Tools for the Job:
- joist detector
- tape measure & pencil
- cordless drill/driver
- jigsaw or
- bradawl or small drill
- Determine the positions of the joists. These are often indicated by the position of the floor fixings or you can use a joist detector. Measure in and draw a parallel line 150mm (6in) out from the skirting board. Place the top edge of the grille on this line and draw a pencil line round it, keeping the ends equally spaced between the run of joists where these run at right angles to the wall.
- Set the grille to one side and draw another line 12mm (9/16in) inside the grille outline. Drill a hole at each corner with a 12mm (9/16in) drill bit, ensuring that the edges of the bit stay inside the second guideline.
- Cut out the waste area within the second guideline, using either a jigsaw or padsaw. Work from each drilled hole. At the last hole the waste section is liable to fall through into the ceiling area. To prevent this, particularly if the grille is so small that you will not be able to get your hand into the hole to remove the cut out section, partially in a large wood to give you something to hold as the block is cut away.
- Remove any rough edges from the hole with abrasive paper before screwing on the grille. Align the edges of the grille with the pencil guideline. Use a bradawl or small drill to make a pilot hole for the and fix the grille in position. For a neater appearance, align all the slots so that they face the same way.
- Where carpet is to be refitted, cut out the hole in the carpeting prior to fitting the grille in place. Then screw down the grille so that the carpet is sandwiched between grille and floorboards. If the carpet is quite thick pile, you may find that you need to use slightly longer screws than those that were originally supplied with the grille.
When determining the position of the grille, use a detector to locate pipes and cables to avoid cutting through these by accident.
Tips of the Trade
When a grille is to be fitted into a polished floor you will want to get the best finish possible. Special jigsaw blades are available that cut on the down stroke and prevent splintering to the floor surface.