Retrofit wind uplift prevention

[viiking]

I recently found a copy of the original Structural Engineer's calculation for a renovation I did 35 years ago! Simple double garage with roof. Nothing special. All approved by Council.

The building of an attached tiled roof garage required three 5900mm wide steel beams of various sizes 310UB 40, 250UB 31 and C channel 200x75.

The last page calculates the wind load (Sydney - Terrain Category 3) and calculates the Factor of Safety as being within spec at 1.35. It goes on to say the three beams are "to be tied to R12 rod (one per pier) rod cast into footing." For whatever reason this was not done and each of the beams is attached to steel spreader plates onto attached piers with no R12 rod.

It has lasted all this time and I have had no problems despite experiencing lots of heavy storms. Lucky? Maybe.

Now in my old age and with concern that I do not want any excuse for an insurance company to deny any damage claim I may ever make because it was not built to the requirement, I am looking at whether I can/should add some sort of hold down ties from the beam to the floor slab. The last thing I want in my twilight years is to worry about losing my home.

So, is there some standard way of doing this? My thought was to just run two steel rods on either side of each pier and bolt it to some steel plate welded to the side of the steel beam and bolted to the floor with concrete bolts and/or epoxy.

The engineering company no longer exists with the original engineer passing away some years ago.

Does anyone have any counterarguments to what I propose? Thanks in anticipation.

[rwbuild]

There is no legal requirement to do this for insurance purposes.

[mic-d]

I wouldn't worry about it. As the old builder I worked with used to say, there are tons and tons of weight in tiles on a roof, but it is a factor to be considered if ever a tiled roof is converted to something lighter like tin. The tiled homes of that vintage or older I've seen around here don't have any tie down. This is of course to be considered my opinion only and not expert advice, don't trust some chump on the internet.