Protecting render from TV mast

[Windmill]

From the street I can see a few cases where a TV mast has been strapped to a chimney (the approved method AIUI) but, despite the metal corner brackets between the strap cable and the chimney, the render has been cracked at the chimney corners and has separated from the underlying brick.

Is there any way to make this less likely, given that a cable would probably need to be under a fair amount of tension to hold a satellite dish firmly in place?

[Andy Burns]

Use of the brackets that uses packing strap instead of lashing wire?

I notice they now sell plastic corners for use with it, which weren't available when I put mine up.

[js.b1]

With render it might be worth isolating the bracket from the surface...

For small items "Rigifix" might work, they use a 10-12mm hole with a plastic plug, then an allen key driven sleeve, then a standard metric fastener (bolt) of M6-M8 can be screwed in preferably with some thread lock compound.

For large items I would 25-38mm core drill via cordless through the render to brick work. Cut some acetal round bar longer than the render is thick, width chosen to fit within the core drilled holes and drilled to take a stainless screw. Drill the brickwork for Fischer SX10, fit together with stainless coach bolts. Silicone around the render-spacer interface.

For a chimney, you run into several problems. Insufficient mass above the fixing. Very tall chimney do flex with a large aerial & gust loadings, or they crack resulting in the bracket pulling a brick out of the chimney (brick shaped hole in stack opposite, aerial & brick on roof). A crack in a very tall chimney will propogate until the thing if lucky starts to twist making it obvious - or simply plunge ground wards.

So perhaps find a wall.