Repointing brickwork joint for flashing

Discussion in 'Builders' Talk' started by binxa, Oct 25, 2021.

  1. binxa

    binxa New Member

    Really hope someone can help please - this is really stressing me out!...

    We're installing 'lead alternative' flashing between a flat roof and adjoining brickwork.

    When cutting a chase in the mortar, way too much mortar was ground out. Basically the void ended up more like 50mm in many places, rather than the intended 20-25mm chase.

    In an effort to rectify this (in a panic!) the chase was then part-filled with mortar (2 days ago), to reduce the gap to the size it should've been in the first place.

    Original plan was to use Lead Mate sealant to seal the joint. Can we still use that to finish the job? If so, I'm guessing that we'd have to wait until the new mortar has fully dried before sticking sealant in...is that correct?

    Roughly how long will the mortar take to dry in the current UK climate? Presumably if the sealant is applied too soon it could cause problems so how can I tell when the mortar is ready?

    Or structurally would it be better to forget sealant now and only use mortar? In which case, can the recently filled mortar be left where it is and we just add more mortar to that, to close the remaining gap (after fitting the flashing)? If so, would the 2 day old mortar need to be left to fully dry/harden before adding more? Does fresh mortar stick to relatively new (but dry) mortar ok?

    Sorry for the long post. Basically I just want to know the best way to fill the joint so I can get the flashing in asap without the wall being structurally compromised any further!

    Thanks in advance!
     

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