Painting masonry window sill

[citizencydonia]

Hi

I am repainting my exterior masonry window sills. They were very flakey, however the flakes are loose in places, at least 50% would be very hard to remove, more like 90% on some sills.

So I have wirebrushed it down to a smooth as possible surface where possible and removed the stuff which comes off easily.

Looking at the pictures do people think I can get away with coating this with a masonry primer and paint or will it show?

Also there are a few round areas now which are at least a couple of mm deep where the paint has come away back to the concrete but all around is too hard to remove. Can these be filled? It feels odd filling just to be level with old paint so I can then paint over the top.

See photos here: https://www.dropbox.com/sh/a8i4jcbtdk3n3qh/2Wt8TIISg2

 

[Bosswhite]

Fill with a good quality exterior filler, rub down and apply two coats masonry paint. Job Done

 

[TheDec]

Citezencydonia,

In the first instance it is unwise to use a wire brush before the application of a water based paint, the reason for this is that any metal particles will cause rust stains and could in time show through your finish coats. Are your sills natural stone, concrete, or sandstone, it is important
for the long term that you can establish that.

Dec

 

[citizencydonia]

Too late on the wire brushing TheDec, however I am not wire brushing the underling material so much as using it to remove the existing flakes and smooth what will not come off (see pictures)

Pretty certain it is not natural stone or sandstone, looks like plain old concrete to me.

 

[TheDec]

If it is sandstone it will need sealing with a sealer specific to the stone.

Dec