Mastic to walk on?

[Daljit]

Hi

I’m looking to fill a gap at floor level in a balcony and wondered what might work best. See pics - it’s poorly designed with door sill ending short of lead covering leading to galvanised balcony, leaving a 15mm channel that will occasionally be walked upon.

Previously some oil based mortar seems to have been used. Should I go for same?

Cheers

 

[opps]

Not my area of expertise but the fact that someone used a screw to hold down the lead looks a bit worrying.

Someone like @crank39 might be worth deferring to.

 

[freddiemercurystwin]

https://www.sealantsandtoolsdirect.co.uk/saw-cuts-and-movement-joint-sealants/sika-everbuild-hybriflex-smp-hm-expansion-joint-sealant-grey-834156-fphybsmpgy