I’m building steps from my house to the garden, where previously there was decking. I’ve already poured concrete for the steps base, leaving underneath a layer of MOT sub base which I compacted. Plan was to use Class B Red engineering brick 2 layers per step and put a concrete paving slab on top, 2 steps total. For filling up the the hollow area I bought Aerated blocks and was going to fill the gaps with more hardcore and concrete - I do not have a concrete mixer, only a drill with an attachment so this made sense and would save me a ton of work.
A friend of mine was visiting and saw this and pointed errors to what I was doing:
- He told me I should use some insulation between house and the steps so that moisture doesn’t raise through them inside
- He told me that the aerated blocks I wanted to use as a filler are like sponges and will hold water and make the problem with damp even worse, he suggested I use salvaged bricks instead
Removing the concrete base is not an option now, so I want to ask if what he's saying has any merit - should I put some insulation between my construction and the house wall? Or should I insulate the bricks from the concrete base? And what about the Aerated blocks, should I replace them for something else?
Including rough top-view and front-view sketch of what I'm doing, which was used to help me estimate how many bricks I'd use