Posts In Rock

Thread Tools Search this Thread Display Modes
Old 04-26-2013, 06:22 AM   #1
BenFencin''s Avatar
Trade: Rural Fencing
Join Date: Apr 2013
Location: Gorham, Maine
Posts: 33
Rewards Points: 37

Posts In Rock

I went out to look at a gate repair on a fence yesterday, somebody else installed it. They used big posts, but after feeling them, and measuring about 5.5' out of the ground, it looks like they are only 8' posts! I'm assuming they hit ledge. I saw a couple outcrops in the driveway, it looks like hard rock, maybe granite. I've put a lot of thought into trying to find cost effective ways to deal with these scenarios, but I need input. Last year I bought a 6" Pengo Agressor auger with Bolt On Rock Head.

I have a tractor with about 19gpm of hyraulic flow rate. My drive unit mounts to the side of the bucket but it's really not enough torque. Stops moving when I apply needed down pressure for rock. I was going to try renting a skid steer drive unit from a rental shop with more torque, plus I should be having it center mounted when adding down pressure. I called Pengo, they told me that the auger I bought isn't what I need for hard rock like granite, that I need a step auger and a lot of down pressure. I'm wondering if I should invest in it, if my flow rate will handle a drive unit for that auger or if I should look into other options. I've never rented a rock drill run off an air compressor, how big can you go with those? Can I drill multiple holes and break it out, put a post in and fill with concrete? I also looked into a product called dexpan, it works like blasting but works slow and doesn't blow up, just slowly expands. I'd have to drill holes for it of course. I also have a SDS-max hammer drill that I've used to drill up to 1 3/8" holes into granite.

I'm open to suggestions.

Here's the gate I need to fix

Cross braces should be 2.5x the height of the top wire. This fence is 5' tall and the cross braces are only 7.5'!

Last edited by BenFencin'; 04-28-2013 at 08:46 AM.
BenFencin' is offline  

Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!




Old 04-26-2013, 09:50 PM   #2
Windwash's Avatar
Trade: Remodeling
Join Date: Dec 2007
Location: Shoreview, MN
Posts: 588
Rewards Points: 148

Re: Posts In Rock

My first thought was rock drill and bust out middle for a wood post like you said but haven't done it. I don't think a wood post in a non draining hole will fair too well but the power companies do it all the time with telephone poles.

Another idea would be to weld a plate to the bottom of a square tube or pipe and drill 4 holes in the plate and secure the plate to the rock with drive-in anchors.


Windwash is offline  
Old 04-26-2013, 10:36 PM   #3
Windwash's Avatar
Trade: Remodeling
Join Date: Dec 2007
Location: Shoreview, MN
Posts: 588
Rewards Points: 148

Re: Posts In Rock

Forgot to add this: You may want to post this under excavating as well as they probably have some good ideas for punching a hole in granite.
Windwash is offline  
The Following User Says Thank You to Windwash For This Useful Post:
BenFencin' (04-28-2013)
Old 04-28-2013, 11:49 AM   #4
GO Remodeling's Avatar
Trade: remodeling
Join Date: Apr 2005
Posts: 2,523
Rewards Points: 96

Re: Posts In Rock

Why do you have to go into the rock? Instead of a circular post hole,why not make a wide base and fill it with concrete? Throw some sand or pea gravel in first for drainage.

Last edited by GO Remodeling; 04-28-2013 at 07:25 PM.
GO Remodeling is offline  

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
I need a laser mechine to cut black rock ranil General Discussion 3 11-19-2012 08:17 PM
Labor rate to hang Rock Victorrmejia Business 1 07-25-2012 11:50 PM
Posts in ground for carport. Chris G Decks & Fencing 7 09-14-2010 09:15 PM
Looking for actual Quiet Rock installations. hornblower General Discussion 1 08-28-2008 06:18 PM
How To - Finding New Posts Nathan Contractor Talk Tutorials - How To Use This Site 12 05-08-2008 11:59 PM

Join Now... It's Fast and FREE!

I am a professional contractor
I am a DIY Homeowner
Drywall Talk is for

At we cater exlusivly to professional contractors who make their living as a contractor. Knowing that many homeowners and DIYers are looking for a community to call home, we've created DIY Chatroom is full of helpful advices and perfect for DIY homeowners.

Redirecing in 10 seconds
No Thanks
terms of service

Already Have an Account?