Replaing a rotten windowsill

[j]

Hi all,
I've got a bay window which has developed rot on the sill. It's a rectangular bay, and the rot has started at one of the mitres at the corner.

I'm looking for advice on how to go about repairing it.

Here are some pics of the "damage"
This first pic, shows the front of the sill, it has rotted from the corner to about 30cm along.


This pic shows a little closer the ro on the front


This one shows the damage to both corner pieces. The rot has only spread a couple of inches on the left piece.


This one shows the sill from above. As far as I can tell, the rot hasn't gone further back than this corner post. That is the point I an considering cutting back to.


The two choices I've though of so far are:
Cut off just the rotten end of the sill pieces and try and fit a new piece to match the original profile.
-Would I be able to get a reasonably clean invisible) joint like this
-Would I be able to match the colour of new wood to existing wood.

Or, try and remove the front couple of inches of the entire length of the sill and replace with a new piece.
-How would I cut this front few inches off? I thought of using a circular saw set to cut almost all the way through the sill(as it's sitting on bricks). Are there likely to be any screws/nails in there?
I seem to remember a chap doing my dad's windows like this about 15 years ago. Not sure how he cut it, but I definately remember him fixing the new front of the sill on with mastick and some plugged screws.

Also, what kind of wood should I use, I believe they are not hardwood windows. Would a builders merchant be the best place to buy it?
Can you get ready made window sill stock. His Normness indicated in one program that it was just something you buy off the shelf. Of course that's over there and we are over here.

Well, after reading all of that, it's quite obvious I don't really have a clue where to start. But hopefully with some advice from the members here I'll be slightly more knowlegable afterwards. (even if it is the knowlege that one should not attempt anything like this, leave it to the pros)

Thanks all
J

 

[John McM]

J,
You can cut out the rotten part of the cill. From the outside tip of the mitre measure about 2 " past the rot along the front edge of the cill. Don't cut the cill at 90 degs to the front edge, instead cut a long diagonal towards the back of the cill. From the short tip of the mitre extend a line parallel to the front edge of the cill to meet the tip of the long diagonal. This parallel line needs to be a little behind the extent of the rot. The long diagonal is called a scarf joint, it provides a good long grain to long grain glue line and also best disguises the join. Cutting wood in a restricted place is not easy, I have found the Fein Multimaster about the only tool that will get in there easily. It is not cheap but has a billion uses. Once you get one you'll never stop finding a use for it. Axminster amongst others sell it. Once you have removed the wood surrounding the rot you'll have to scarf in the new pieces. Carefully trim and measure, cut the mitre and glue and plug. Pre-treat the wood with clear preservative. Anyway hope this made sense.

 

[Max Power]

J ,judging from the photographs, your window appears to be of standard softwood construction, with a microporous woodstain type of finish such as Sikkens etc . In this case they are most likely to have had the external cill section fitted seperately to the main part of the window frame.If you dig part of the rotten cill away you will see if this is the case, there should be a tongue at the back of the external cill section fitting into a corresponding groove in the frame itself.You would then be able to prise the external cill away from the main part of the frame and replace it with readilly available new sections from a local timber merchant hope this helps.

 

[Marky]

Hi J.

I do countless repairs like this, and I find both the quickest and the best solution is to use a product called 'dryflex RP'.

It's like a filler and an expoxy resin in one.

I personally would cut all the rot away, and be harsh with this, cut it all away.

Then using some scrap perpex or rigid plastic, shutter underneath. Then shetter the front face. These are the two flattest profiles.

Then using a filling knife completely fill the void up to match your cill profile in one go. Leave it 24 hrs, break off the shuttering and sand with a detail sander, apply brown sadolin or sikkens and your done.

With a little care you will get a perfect finish that will never (ever) shrink away from the existing wood.

If you want to save a bit of filler you can butter some pre cut timber in first to save some of the bulk of the filler, up to you.

From what I can see you will need 1 x set of the stuff.

You can get it from here.

http://www.wincareang.co.uk/

Regards

Marky