Repairing Crack In Stone Window Sill ?

[WhiteVanJack]

Hi,

I have a stone window sill that has a crack across the top face progressing down the side. Would anyone please be able to advise me what my best options are to repair the window sill?

I intend to remove all the paint that is currently on the window sill and get it back to bare stone as smooth as possible then repaint it with a matt black masonry paint. Hopefully the repair can be done before repainting.

I have uploaded a picture of the window sill & crack below. Any advice on how to repair it most appreciated.

Untitled

• WhiteVanJack
• 7 Sep 2010
• 1

Rgds
Jack

 

[PrenticeBoyofDerry]

After you have removed paint, rake the crack out so it is a little deeper, so you can get a good repair fill into it.
As you are re-painting the cill, the repair colour should not be a great issue.
So I would just use a normal mortar compound to fill the repair in with, filling it to level then let it stiffen up a bit and wipe any excess around the repair off with a sponge or rag.

 

[WhiteVanJack]

I would just use a normal mortar compound to fill the repair...

Many thanks for the advice.

Would you please be able to elaborate on "normal mortar compound"? For example is this something I would buy made up or just a straightforward mix of sand and cement in a specific ratio?

I actually have a small bag of "Instacrete 5" unopened and dry. It states on the bag it is quick drying cement with a 5 minute drying time. Would this be a suitable alternative to a mortar compound for repairing the sill?

Apologies for such a basic question but its just an area I am not familiar with.

 

[PrenticeBoyofDerry]

I have just had a look at the spec and should be fine.
Just try to get the repair as flat and even as possible.
Also follow the instruction given with the Instacrete 5.

 

[masona]

Something like this will be okay, Jetcem, just add water about £3-4 ish, I thinking without sand as the crack not wide enough for it and easy for fine filling

Rapid setting cement. Patching / repair compound sets in just 30 minutes for permanent repairs to stone, brick, concrete and render.

 

[ladylola]

If you require a stonger repair, for example if there is weight upon the stone causing it to crack there is another option we employ quite often.
You would need to cut two or three channels at 90* to the crack, around 6-8 inches long and about an inch deep. Into these channels resin a lenght of spiro tie or 1/4" allthread and then point up as suggested above.

 

[WhiteVanJack]

Thanks for the replies everyone, they are very helpful.

masona,
I think the JetCem is a similar product to the bag of Instacrete 5 that I have as they are both rapid setting cements. They do seem appropriate for this type of repair.

ladylola
That's quite a creative solution. My only concern about cutting channels at a right angle to the crack line is that the vibration from cutting could cause things to worsen. What would you recommend to excavate the channels, an angle grinder or chisel?


Rgds
Jack

 

[ladylola]

An angle grinder would do the job, cut several grooves which make it easy to remove the debris.The bottom of the groove doesn't need to be neat indeed it's better that it isn't for keying purposes.
We also use the fein cutters which are an expensive piece of kit but very useful, the diamond blades cost a small fortune.

http://www.fein-uk.co.uk/corp/uk/en/products/index.html