window cill

[andy999]

how do i fit a new window cill, (internal)
mine is wood in the bathroom and rotting, i want to replace it with plastic, any tips?

[noseall]

andy999 wrote:

how do i fit a new window cill, (internal) mine is wood in the bathroom and rotting, i want to replace it with plastic, any tips?

yeh, don't fit plastic sills.

[Richard C]

Use Polyboard, it's pre-finished similar to worktops; it’s more expensive but looks much better than painted wood or plastic, particularly with UPVC windows. If the cill hasn’t been replaced before it’s likely to be buried in the window reveal at each end & can be tricky to get out without damaging the surrounding plaster. You need to cut through the old cill in the centre (tricky & needs care with the window still in place!) so you can lever each half of the cill up & pull it out towards the centre away from the reveal. Once you’ve got it out, make sure the reveal (under the old cill) is sound & flat, cut the new cill just slightly longer than the window opening so you can position it with each end just under the plaster. Use either an industrial strength grab adhesive or low modulus window grade silicone sealer to fix the new cill in place – don’t take too long! You can get plastic end caps to cover the exposed cut edges of the board, stick these in place. Once it’s dry repair any damage to the surrounding plaster &, if necessary, run a thin bead of white decorators caulk around edges to finish off.