Best outdoor sealant for salty sea air (that lasts) ?

[whitedragon101]

I need to seal my balcony from the outside using scaffolding to reach it. Its a 5th floor seaside balcony

https://imgur.com/a/uaZNU3O

(pvc windows, painted concrete, brick)
and when the storms come off the sea the wind driven rain absolutely lashes the windows and balcony and it gets in and we just can't seal it from inside. I thought that CT1 was the best thing from the job but the property management company said their surveyor in the past had recommended Nitroseal MS60 because it does well long term with the salt air of the sea and doesn't dry out and crack after 5 years as some others do. On the website it doesn't look anything special though and only £3.90 a tube compared to £11 a tube for CT1.
Given that the scaffolding to get out there to do the sealing is thousands, what sealant would be the best thing for the job to :
- seal the rain out
- withstand extremes of weather (south facing heat in the summer up to 36c, windy cold storms in the winter down to -7)
- withstand the salt air and last for many many years (20 would be good) without cracking or leaking.
http://www.ct1ltd.com/our-products/ct1/
https://www.fosroc.com/product/show/nitoseal-ms60

[arco_iris]

Seeing the thread title I was going to say CT1 (or there are many other MS sealants available) then I read it.

I suggest explaining the issue to each of the manufacturers' technical departments in detail with pictures, asking for their advice - see who gives the best answer. You could also put the problem to RIBA & other industry bodies to see what they say, there must be lots of advice out there as your situation is not unique.

I have no experience of your particular circumstances but you need a "belt & braces" approach to ensure longevity. For instance you could research the (possibly messy) method of applying the sealant thickly to the joint, bedding glass fibre rope into it then when that has started to cure, go over it again, but double the width this time.

MS Sealants can be smoothed like silicone, and even worked as they cure.

Given the cost of the scaffolding & once in a lifetime access, I don't think that you, OP, should treat this as a DIY exercise as seems to come across, so this forum is not really the best place for definitive advice.

[boxedin]

Could be worth looking at marine ones that high UV resistance
https://www.pbo.co.uk/gear/which-adhesi ... best-20877
https://www.marinescene.co.uk/product/1 ... gIUr_D_BwE