External sealant between brickwork

[FGREEN]

Hello, I live in a bungalow which has an extension to the rear. This is brick built but where the extended portion meets the original brickwork it is not tied in. So I have 2 walls alongside each other and I believe there is some sort of metal plate running down the inside and this was then “mortared” over. Over the years this has cracked and dropped out in some places and I need to replace it. I am thinking of using some type of flexible sealant.
When I have looked around at some other brickwork with large areas that “butt up” to an adjacent wall there seems to be some heavy duty sealant used - perhaps 2 or 3 cms wide. Can anyone advise what sealants I should be using? I find it difficult to search on internet correct terms. I just keep coming up with external frame sealant etc. and I think I need something a bit sturdier.

 

[Retired]

Hi,

You could use trowel mastic if you don't want to use mortar? The mastic needs packing tightly in then allowed to skin over if you wish to paint it using oil based paint or it can be left bare; mastic has been around forever; I've just been using mastic to seal the wooden joint between porch and stone wall.

https://www.ebay.co.uk/itm/EVERBUIL...459045&hash=item4b5c9a17d7:g:bpsAAOSwsQJcVGUR

Kind regards, Colin.

 

[FGREEN]

Thanks for your prompt reply. I hadn’t considered mastic as I thought it might be inflexible and in your application would have thought against the wooden window frame there might be movement that would lead to cracking. Is it in fact capable of absorbing small movement?

 

[Retired]

Hi,

You're welcome. The mastic will possibly crack over time but is easy enough to make good again. Mortar is cheap and was originally used but as you've found out mortar is unforgiving regarding movement. There are many types of modern sealants on the market but I tend to stick with old and tried methods tested over years; perhaps other members can chip in with more suggestions?

Kind regards, Colin.