Mortar for window sill repair - Window sill repair

[skweem]

Hi all - I need to make a repair to a stone window sill and will be using a wooden former. A book I have tells me that I should use a 'ready mixed quick-setting water-proof mortar'. Would this be granolithic mortar? and if so can it be purchased via most building supplies outlets?

Many thanks

[danensis]

I seem to recall some mention of Fosroc in this context? Mortar doesn't tend to bond very well to stone due to the differential coefficient of expansion.

[skweem]

Thanks very much Denensis - your frighteningly technical reply might explain the reason why I'm having to make the repair in the first place as the sills have previously been coated in some sort of render.

I'm wondering whether casting a whole new one in situ or buying one ready made might be a better option given that I don't want this to be a regular occurance. I quite like the option of casting a new one in situ; your advice on a concrete type and mix would be very much appreciated and any advice regarding reinforcement.

I would be grateful for details of the specific Fosroc product should it come to mind.

Many thanks

[mouldmaker]

If you decide on ready made, I can help. We have a wide range of standard sills or can make bespoke to suit your needs.

Albion Architectural Concrete

[skweem]

Thanks Mouldmaker - The work to be carried out is on a house I'm buying; when I get in there will have a closer look at all the sills to see if more than one needs doing and if so will probably get in touch.

Have had a look at your website and the products look great. Will definately give ready made some consideration.

Thanks