Removing an internal window sill

mp80

Hi
My bathroom sill needs replacing as it has rotted due to a shower running onto it for a long time (my fault)
I don't think that it can be repaired as it is too far gone
Is it an easy DIY job to sort out without removing the window itself? If so can anyone point me to some guides?

Hector-The-Inspector_2

You could cut along the sill with a broad wood chisel and hammer without disturbing the frame, renew with timber or uPVC.

andrew-b

The sill will butt up against the window frame rather than going under it so there should be no need to remove the frame.

There may be a wooden or plastic beading between frame and sill finishing it off - carefully remove it (preferably without breaking so you can reuse it).

Carefully cut along the edge of where the sill meets the walls so that you don't tear off the wallcovering or paint on the walls.

If your lucky the sill won't be rebated into the plaster of the window reveal and it will be a simple case of whacking a bolster chisel or crowbar underneath it to lift it up and lever it off (careful you don't put your tools through the glass!) - should be fixed with screws or nails. You may not even need that - my Dad as a building surveyor very often lifted them with his trusty penknife!

If your unlucky you may find the sill is rebated into the plaster either side of the window reveal which will make removal far more tricky and messier. This was the case with our bathroom windowsill - what we thought would take 5 minutes turned into a much longer job and involved chopping out the plaster and using brute force in order to break the sill to get it out.

Once you've removed the sill you may need to make good the area underneath and ideally make it level (else you'll have to pack the new sill out to make it level when fitting).

For the new sill i would avoid uPVC (scratches easy, looks a bit cheap IMHO, and can yellow). We got pre-primed MDF windowsills from Wickes . You'll need some basic woodwork tools (and skills) in order to fit it. Don't assume the angle between window and reveal is 90degrees as it may not be. Use a combination square to transfer the angle onto your new sill. Sills look best if you cut them around the reveal of the window so they overlap with the walls either side by a short distance - but copy the way other sills in the house are fitted. Mark out your new sill carefully ..the old adage "measure twice, cut once" applies! I find it best to do one end first check you've done it right then do the other end. A jigsaw is ideal for cutting the sill. With MDF remember to wear suitable mask as well as eye protection as MDF dust is carcinogenic. Once you've got your sill cut to size use a file off the corners (again copy how other sills in the house are finished off).

To fit the sill you could just stick it with No Nails - though i'm more of a belt and braces person so i use screws as well! If it's not level then you'll need to pack out the sill with whatever you can find (bit of hardboard or wood offcuts are useful or pieces of ceramic tile). If your using screws then drill holes in the sill (ideally a pair of holes either end and in the middle) and countersink them. If the cavity is open you'll need to ensure the holes line up with the brick/blockwork ..if it's closed it doesn't matter so much but i'd still aim to be fixing to the bricks/blocks. Position the sill, drill pilot holes through the holes in the sill into the masonry below, then remove the sill and drill and plug the masonry. Screw your sill down (packing where needed). Then fill your screw holes with filler, replace beading against the window frame to cover any gap (i've still got a 10mm gap to cover on our bathroom sill!), prime, undercoat and topcoat.

Hope that helps as a general guide..i'm sure everyone has their own methods of doing this!

Andy

27col

There are several different ways of fixing window boards. Some are just nailed down, often using large cut nails. Some are screwed, some are fixed using a wire fixed to the underside of the board and secured to the wall under the plaster. There is no correct way to remove the board, it really a case of "suck it and see". It all depends on the method used to fix it in the first place. You will be lucky to remove it without some plaster damage. Once I removed one by splitting it with a large chisel down its length. If, as you say the board is rotten then it ought to slit easily.
MDF does make a very nice window board, I think that you can buy it ready primed.

Mikeyorks

27col wrote: »

MDF does make a very nice window board, I think that you can buy it ready primed.

You can also buy it with a machined 'bullnose' so you don't have to mess about shaping the inner edge. And although MDF is 'inert' ..... you can also buy the bullnose stuff (specifically for cills) pretreated with a preservative. It's green inside ... as witness the mess I cleaned up when the joiner made our bath side using a piece of treated window board as the top edge.