Damaged exterior render on border - suggestions?

[Loki7430]

This is the end wall of my house a 17c cottage. The border section has at some time in the 80's been covered in bitumen as part of extensive damp proofing work (I'm sure it seemed like a good idea at the time) and is starting to suffer a little. I've scraped off the really loose bits and now am wondering what to do.

Is it worth filling/patching as is? Or shall I remove the remnants of the bitumen (with chemical remover) first then patch up or is it too much of a mess and needs completely redoing. Your advice is appreciated.

 

[Flyfisher]

You don't mention if you actually have a damp problem, but I think bitumen plinth paint is a fairly common treatment on period properties. Our house was treated in exactly the same way.

I don't know what's best for your house so can only relate what I did for ours. Basically I removed all the loose and flaking bitumen, which also removed some of the crumbly underlying lime mortar. Where necessary, I patched up any exposed holes and/or pointing with lime mortar and then repainted the border with black limewash. I'm assuming that over time the remaining bitumen paint will flake off and I'll repeat the process when it looks too shabby.

This may not be the 'perfectionist' approach, but to my mind it leaves the wall more breathable than it was previously and over time all the bitumen will weather away and repainting the border with black limewash every few years is not too onerous.

 

[tobydog]

FF - you mention that you've used "black lime wash". This is exactly what I need for my bitumen covered plinth because, whilst I've removed most of the nasty bitumen, I still have some persistent parts that refuse to budge. I need to re-point and then cover. Is it actually black lime wash or is it black plinth paint? I've seen adverts saying that plinth paint is breathable but I've not been totally convinced it would be as good as lime wash.

 

[Nannynags]

It noticed while going through other items on this website that you can buy a coloured Limewash. Im sure other companies will do it too. Just so happened this is close to me so tends to be my go to place for lime products. http://cornishlime.co.uk/cornish-lime-unadulterated-limewash

 

[Flyfisher]

Definitely not 'plinth paint' as I, too, am very dubious about the breathability claims. I bought the black limewash from Ingilby Paints, a small family-run business in Suffolk: http://www.ingilby.co.uk

They actually call it 'Blackish', probably for some purist technical reason but I can assure you it's as black as any black paint I've ever seen! Check their website as they have slightly different formulations depending on the application. I chose the limewash and tallow formulation but you can buy it as unadulterated limewash if you wish.

Any questions, give them a call - they are very helpful and knowledgeable.