Would concrete padstones always bonded in the wall using cement based mortar?
Scenario:
Concrete padstones to spread the load of the steelwork located in an old solid brick masonry bonded with lime. Should the padstone be bonded with modern cement based mortar or using the same mortar of the old bricks bond?
Technically cement based mortar would be strong on the old hand made clay solid bricks, I’m wondering whether this would create cracks, bricks problems over time, hence, structural isssues.
Replies
What did you decide to do in the end? I am currently preparing to install padstones in a 1860 victorian terrace and want to use lime mortar to bed the padstones, I am just waiting for my SE to confirm I can do this.
I used a mix using Vicat Prompt natural cement, a good compromise between strength and "heritage spirit". Less strong than portland cement but stronger than lime. However, it sets extremely fast and I recommend everything ready to be installed once before mixing, you ill literally have 5min. Mix in small batches.