The decking that pre-dates my purchase of my house has finally reached the end of its service life, being rotten within many of the boards and some of the bearers, underneath. I pulled it all apart over the last couple of day s and what I'm left with is three, parallel, brick-built supporting "walls" , running about 8m in length and with a span of about 4m (i.e.~1.33m betwee n each wall).
During removal of the old decking, after taking off all of the decking boar ds, I noticed that where the bearers sit on top of the brick walls, there w as quite a bit of packing material (slates, tiles and other assorted shite) underneath various of them. This packing material was presumably used to l evel the bearers and was required because the three supporting walls themse lves are not all at the same level, all the way along their length. The amo unt of correction required ranged from zero to a couple of inches, although it's probably worth mentioning that the less packing was used on top of th e outermost walls than the central one (i.e. the central wall deviates from the mean height to greater extremes than the others).
In an ideal world, if I had plenty time on my hands, I'd pull the whole lot down and build new brick supports for the bearers. Right now, though, the better option is to find a way to level the existing brick work. One notion that occurred to me is to clamp some shuttering against each of the walls, with the top of the shuttering at exactly the same level, all the way alon g all three. Then, I could fill the troughs created by the shuttering with cement/concrete, producing level upper surfaces to all three walls.
Is the shutter-and-fill approach sensible, or are there other, better ways of doing this? From previous experience, I tend to think that thin layers o f cement or concrete can show poor long-term adhesion an can be prone to cr acking and breaking-up in freezing weather. I'll probably stay living where I am for a good few years yet, so I'd rather not set myself up to have to re-visit this job any time soon.