I've got a commercial property on which I need to set several corners. They will all be in a concrete sidewalk. The sidewalk is only a few years old.
Most of my work is residential and I can usually just set an offset corner when one falls in the concrete. That won't work this time. What do you guys find works best? I don't want to make a mess of the relatively new sidewalks.
Lead plug with a brass nail is the common answer for this problem here.
Lead plug and washer. What does your State/County/City allow you to set?
If they want bars set you will need a good drill bit in a portable drill or be prepared to spend a lot of time with a handheld star drill.
Mr. Smartbutt initially thought of suggesting a pretty little circle of orange paint.:-P
Not just for concrete. If you're REAL careful you can set those in marble tile inside a train station lobby.
:good: :good: :good:
These things are great. The drill bit does a nice job of recessing the monument. You end up with a first rate monument.
They are the only option allowed, other than a iron rods, for plats in the tri-county area surrounding Portland.
Others in the area have set P.K.'s with a washer containing license #. I do that too, but I'm afraid I'll bust up the concrete. Could I use a hammer drill to pre-drill for the P.K.?
Drill a 1/4" hole with a hammer drill using a good masonry bit. Drive a mag nail with washer into the hole, it won't come out. It will sit up on top of the concrete so snow removal (if you have snow) equipment may hit and knock them out. I think the Berntsen markers are flush but I've never used them, just heard they are the best.
On a closely related note...
Due to the increased value of land here, our new City Engineering Standards allow sidewalks to be constructed so that the back edge of the sidewalk falls on the front property lines. We are now faced with setting a monument that falls on the very edge of the sidewalk. The developer frowns on us damaging the sidewalk, and we don't really like breaking out a piece of sidewalk every 60 feet. If we leave a rebar or rod sticking up a few inches we are concerned about people tripping on or falling on them, even with a cap. We are required to set a magnetically detectable monument. MAG or PK nails with washers will not stay in place under ANY circumstances with ANY type of adhesives due to freeze/thaw.
How do you guys deal with this?
I had to set about 200 of these to mark the centerline of a long tunell a few years ago. They worked great especially with cordless Bosch Drill and the drill bit you can buy to countersink them.
Educate me
Why are the Berntsen markers copper, when bronze is more common for disks? When is one better than the other?
On a closely related note...
I use a cold chisel to make a "+" 4" to 6" in length then set a my typical monument 5' away on line.
On a closely related note...
> Due to the increased value of land here, our new City Engineering Standards allow sidewalks to be constructed so that the back edge of the sidewalk falls on the front property lines. We are now faced with setting a monument that falls on the very edge of the sidewalk. The developer frowns on us damaging the sidewalk, and we don't really like breaking out a piece of sidewalk every 60 feet. If we leave a rebar or rod sticking up a few inches we are concerned about people tripping on or falling on them, even with a cap. We are required to set a magnetically detectable monument. MAG or PK nails with washers will not stay in place under ANY circumstances with ANY type of adhesives due to freeze/thaw.
>
> How do you guys deal with this?
I would think that setting an even foot offset to the corners would be best (witness corner). I would try to make a standard offset distance for all of the corners to be the same. Make sure all the rods are flush or below-flush with the ground to prevent tripping or lawnmowers hitting them (but you would probably do that anyway)
Educate me
> Why are the Berntsen markers copper, when bronze is more common for disks? When is one better than the other?
They look like copper, but are advertised as being brass. I think there's probably zinc in the mix to provide strength, but maybe not as much as in more common brass alloys. I don't have any specific information about the alloy, though.
Bronze is preferred when resistance to salt water is a factor, as the main alloying ingredient -- tin -- doesn't leach out.
2" aluminum cap on 5/8" rebar, cordless Hilti hammer drill for the 5/8" hole then a different wider bit to widen the top of the hole to recess the cap. works like a dream, set hundreds of them. It's easy, if you a lot of them buy a Hilti, if you only do a few-rent one. Just don't set offset points just because it's concrete, much better to set the actual point and it's isn't a big deal at all
> 2" aluminum cap on 5/8" rebar, cordless Hilti hammer drill for the 5/8" hole then a different wider bit to widen the top of the hole to recess the cap.
Regulatory requirements aside, why would anyone want to drill through a concrete slab to set a rebar? It seems to me that either the slab is stable enough to warrant drilling and fastening a disk directly into the concrete, or the slab is unstable enough to displace the rebar and render it unreliable.
On a closely related note...
That's exactly what we do. Gets a bit tricky with side lot lines that intersect at oblique angles...
"Regulatory requirements aside, why would anyone want to drill through a concrete slab to set a rebar? It seems to me that either the slab is stable enough to warrant drilling and fastening a disk directly into the concrete, or the slab is unstable enough to displace the rebar and render it unreliable."
In my climate the freeze/thaw cycle pops a disk out relatively quickly no matter what adhesive you use...
On a closely related note...
I like to drill a hole in the concrete, drive a re-bar down though it until below the concrete by using a punch. Then fill the hole with lead and then drive a PK into the lead plug until it's top is flush with the surface. End up with a visible marker and when the sidewalk or ditch liner or whatever the concrete was pored for is broken or removed, the re-bar is in place for a magnetic signature and a visible marker preserving the original position. Have not had to do a bunch of these at one time, if I did, my tools would need upgrading for more efficiency, also keep in mind that the fresher the concrete the easier the hole making. Only way to mark the re-bar is to dig out under the concrete until you can place a cap on the driven re-bar, which I have so far, been able to do or to stamp the sides of the re-bar before setting which I have not needed to do yet.
jud