London Victorian Terrace Bay Window repair

[Edzy55]

Hi All "UK Diy'ers"

This is my first post so be kind. Basically, after the summer of looking at our bay window and wanting to give it a new coat of paint. We started on sanding and stripping the old paint off. Very soon we found that the last paint and repair of the window was a bit of a make good job. The past person had obviously filled in here and their with filler that had gone soft over time. Also silicon had been applied to fill gaps between the concrete sill and pvc windows. The more we sanded the stripped paint the more the bay window fell apart before our eyes and looked to be in poor shape. I've already concrete rendered the uprights of the bay window so they look good and to also add some strength back to it.

The main problem now left is the sill which is worn and needs to be brought back to a sharp square sill. It's worn and rounded off. Do I now either concrete render each side of the sill using boards and g-clamps one at a time as I've read off here somewhere. Or do I make an insitu cast to fill it in then. I just need to gauge the difficulty of cosmetically making the best of the above I can. Is this something anyone can help me with or done before. Some pointers? I want to do a good job and don't want to have to come back to it next year.

Thanks in advance, I'll try to post some pictures if this would help.

Thanks again

Edzy55

[Chris Bacon]

Putting some pictures on a site somewhere (else) would be a very useful thing.

[Dave Plowman (News)]

A rendered repair will soon give problems. A permanent one would be to remove the old stone and cast a new one in situ using reinforced concrete.

[John]

You may find Belzona have a product to do the job. However cheap they aint!

[Andrew Gabriel]

That's a bit sweeping. My rendered sills are now 100 years old, and mostly in excellent shape. I thought they were cast-in-situ concrete until I came to remove one, and found it was a rendered skin over bricks. Brickie told me this is actually very common on Victorian houses.

[Dave Plowman (News)]

I was thinking of a rendered repair to stonework which is likely to be fairly thin to just repair erosion, etc. Obviously if you design the sill from the outset to allow a reasonable thickness of render it should be ok.

I had exactly this problem with my Victorian bay sill which was three bits of stone. Did a render repair just about every re-decoration time. ;-)

Eventually, removed it all and cast a complete new one in situ in reinforced concrete which has been fine - and really not that much more work than rendering.