Consdering installing a security post at the end of my tar-mack drive. The type that I can let down. There are two security posts on the market, those to cement in and those using 12mm anchor bolts. I have never used these bolts before ,so I presume you drill a hole first. Considering thin layers of tar-mack, Are the bolts likely to hold ? Or should I go for the ones that cement in ,thus making a mess of the drive? Peter.
What's under the tarmac? Concrete or compacted ground? Anchor bolts will only be secure in concrete.
In message , Peter C writes
I put one in our old drive. Tarmac on a compacted sub-base, I can't see that I could have sensibly bolted through into this securely - if it was laid over on old concrete drive then maybe ok.
I used a sink in one. IIRC it required a hole about 12 inches square. Concreted in upto a little below the surface and then patch with a bit of cold cure patching tarmac stuff. Once the stuff had weathered it wasn't really noticeable at all.
Problems -
I installed the cheaper of the two on this page:
Anchor bolts only hold in solid materials, such as concrete or stone. So unless your tarmac is over concrete, they won't hold.
In article , Peter C writes
As Dom says, anchors won't hold reliably in tarmac and security posts are a difficult fix anyway as they have a lot of leverage over the fixings.
If you are absolutely sure there are no services under the spot then you could nail a mounting plate into the ground using long spikes (60cm long good, 1m better by 12 or 16mm) and weld the top of the rod to the mounting plate. You could tap the mounting plate for the post fixings or weld nuts on the bottom. Excavating a little tarmac from under the plate and adding a mortar grout would make a suitable bed. If you don't weld then you may get away with threaded rods but they may buckle under hammering, and add the fixing nuts and spring washers before you start hammering as the end of the rod will become mush, cut of the surplus.
Thanks for all the informative replies, tarmac not ona firm base ,I will have to have one concreted in. A good point about servives also. Peter C
Thank you all for the informative replies. Due to the tarmac sub base I will have to have a post cemented in. Good points also re services. Peter C
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