Repair damaged exterior window sill

[Boldzak_DIY]

Hi

One of my exterior window sills has lost a chunk (or chunkS) to be precise.

I'm not sure what the material is - cement with stones mixed through I reckon. The steel (?) support bar has rusted presumably causing the damage.

As it's an unusual material, a 'fresh' repair would probably look out of place, so any tips on repairing using the pieces or is it a lost cause? If that's a no-go, who would I approach to do a repair as close to the original as possible?

Photos of damaged area & close-up of material:



Many thanks

 

[Boldzak_DIY]

Anyone?

 

[wessex101]

It would be very difficult to achieve an invisible repair and to get a specialist concrete repair contractor in prohibitively expensive.

You need to clean the exposed steel reinforcement and treat it with a rust inhibitor. Then build up the sill with an epoxy repair mortar to match the original profile. You could try applying some red spar chippings into the final coat of repair mortar but I doubt you would get a match so maybe just paint the sill to hide the repair.

 

[Boldzak_DIY]

Thanks Wessex101, much appreciated. Something like this? http://www.diy.com/departments/sika-sikadur-epoxy-mortar-2kg-tub-enclosed-sachet/35584_BQ.prd

Presumably not too thin so as to slump

 

[wessex101]

Yes, I've only used epoxy repair mortar a couple of times and I found it very difficult to work with. You can vary the mix between a very liquid almost pourable slurry to a firm mortar. You will probably need the firmer consistency and build the repair up gradually applying a layer letting it set then applying another layer etc. etc. But like I said I have limited practical experience, I've watched concrete repairs contractors use it and they make it look simple but then a good tradesman always makes it look easy.
By the way you can get cheaper repair mortars. I got mine from the local builders merchants (with a good discount) and people like Toolstation stock it.

 

[^woody^]

You will probably need some sort of temporary shutter underneath to hold the repair up. And maybe a couple of stainless steel pins drilled in to reinforce the repair afterwards.

Afterwards, coat the top of the whole cill with a clear water repellant

 

[Boldzak_DIY]

Thanks guys, I'll give it a go. If it's not a complete mess, I might add an 'after' photo