Took delivery of our vertical designer radiators today.
I knew I might have problems drilling into these walls but didn't realise it would be quite so bad!
I marked up and drilled for the brackets and, as expected the drill bit took a detour into the gaps between the aggregate and made a right mess of the wall.
For those of you unfamiliar with Wimpey no fines concrete, it was a method of building houses quickly with a concrete mix of just cement and course aggregate (no sand hence "no fines"). The concrete was cast in situ using reusable formwork and pretty much resembles a giant rice crispies cake slab in grey!
So after completely messing up fixing holes for the first 2 brackets, (2per bracket required x4 brackets) realising the holes were not going to be aligned, and that the aggregate was being dislodged by the drill, I decided I would not drill any further holes until I find a solution.
I have read that there are some 2 part resins available for fixing anchor points where masonry is liable to crumble and I'm wondering if I could use this stuff to fill the holes and then redrill them, but I'm not sure if it will just pull out of the wall in a big lump!
This is what I'm left with...you can see the aggregate in the holes, after I've removed the dislodged pieces....