Correct installation of acrow prop support

I have a failed corner steel post from severe rust between the concrete slab floor and the roof joist. There is residual post support preventing roof collapse. I can not get a builder for at least 12 months so in the interim I want to put up acrow prop support as a safety measure although builder states that a roof collapse in 12 months is unlikely.


I plan to put up 3 acrow props on the inside of the floor to wall windows with the base plates attached to a timber base and structural timber attached to the top plates. the acrow props will be around 900 to 1000 mm apart so I can provide support under 4 ceiling joists which are spaced about 600mm apart. The structural timber will sit under ceiling plasterboard. I will probably brace the acrow props to each other.

Even though I have tentatively spoken to structural engineers, I am not going to engage one for this temporary measure as acrow prop support should far exceed the original load support by steel post before it rusted. The acrow support was suggested by a builder.



I would appreciate any advice or comments particularly on the proposed temporary measure, the type or specs of structural timber I should use, is it possible not to damage the plasterboard ceiling,

I may even decide to replace the post myself if it is not beyond my skill level but there are 2 month delays to get plates welded to SHS steel and to get it hot dipped galvanised. I also have to remove any rusted steel from concrete slab (post was concreted in) and repair concrete to provide a base for new corneer post.

It all looks good. Is it a skillion roof? are you holding just ceiling or roof loads too? You only need 2 acrows and bigger timber under the plasterboard. Just screw that timber, 2x 90x45 would be ok or a short piece of LVL similar size to the ceiling joists, then screw acrow to timber do it doesn’t fall on your head.

The steel post could also be sandblasted and epoxy painted with industrial coatings. Remove all rusted existing post, prime and exposed reo and patch repair with epoxy repair mortars.

Thanks for your input. It is a skillion roof carrying both ceiling and roof loads. I didn't think of LVL so I will look at this option. I will be screwing timber into top and base plates.