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Replacing Mastic in Brick Wall Expansion Joints

Postby PaulJohnson » Mon May 07, 2018 2:34 pm

My house was built 26 or 27 years ago. The garden wall is brick, about 6 ft high, with expansion joints every few meters. These joints were originally sealed with some polystyrene foam and brick-coloured mastic, with a void in the middle. There were no debonding sleeves across the joints, so some of the wall segments are now a bit out of alignment.

The mastic has now degraded, exposing the polystyrene underneath. In some of the wider joints the mastic has failed complete. The widest joint is 3.5cm wide.

How do I fix this?

- What kind of mastic should I use, and how should I apply it? Is it piped on, or do you use a trowel?

- Should I use polystyrene underneath the mastic? If so, what are these things called? (so I know what to order).

- Is there a better alternative that won't need replacing in another decade or two?
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