New Fence Project

[cdaiscool]

Hey guys. About 2 weeks away from starting a new fence project, thought I'd rack your brains for a minute.

Found metal posts for a decent price at Menard's (https://www.menards.com/main/buildi...tal-fencing/8-post-master/p-1444439143296.htm), going to use those set in Fast Setting Quikrete. Doing a 6' shadowbox, found instructions from Master Halco on how to build it (https://www.masterhalco.com/wp-content/uploads/2017/09/PM-Install-TearPad-011480-English.pdf).

Their instructions are based on 90 deg. angles, but my back yard backs up to someone else's at a 30 and 60 deg. angle. Thoughts how I could overcome this?

I don't think I can swing the cedar stuff, I've heard rumblings about 'cedar tone PT pine' stringers and pickets. Yay? Nay?

Current plan is to put the post 2' 8" into the ground on a several-inch bed of gravel, use the Quikrete to set the posts in a 10" wide hole - post is 3.5" so this should be good?

Finally, anyone know where I can get the post clips they call for? I haven't found them on any sites, don't know if Menard's carries them or what.

 

[LifeLongWNYer]

I used to design fences around large plants, some of which required high security, so the posts and fabric were higher than normally found. I consulted in many areas of the country, but I always specified that the installer dig the post hole at least as deep as the lowest commonly occurring frost level. ( Ask the AHJ for the local conditions )

Also, the hole ( and the concrete in it ) had to be wider at the bottom than at the top. This is so that the frost can't force the post, and concrete, up over time. If the concrete in the hole is straight sided, from the bottom of the hole to the top, or if it is wider at the top, the frost will work the post out of the ground over time. It won't happen in a year, or two, but my goal was to design fencelines for the long term.

Yup, I know it cost more, but it is less than doing it two or three times over the normal life of a fenceline.




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[nolimits76]

Also, the hole ( and the concrete in it ) had to be wider at the bottom than at the top. This is so that the frost can't force the post, and concrete, up over time. If the concrete in the hole is straight sided, from the bottom of the hole to the top, or if it is wider at the top, the frost will work the post out of the ground over time. It won't happen in a year, or two, but my goal was to design fencelines for the long term.

Interesting. When reading the linked install article I noticed the "bell" shaped footings (wider at bottom and narrower at top). What device was you using to dig these?

I only ask because in building bridges, we utilize drilled shafts typically from 48" to 96" in diameter depending on the size & spans. In about 20 years I've seen ONE job designed with a bell type drilled shaft. The equipment to drill those type of shafts are not readily available. Most our shafts range in depth 20-100' with the last 5'-20' (conditions vary) going into the rock bed. Due to the complexity of digging bell shaped holes without the right equipment in those depths was not something we were interested in so we passed on the job.

That said, all the other shafts built in OK, AR & TX that I've been a part of is NOT bell shaped and none of them are lifting up. Maybe this is a location based issue, or site specific soil condition?

 

[The Cobbler]

I agree on the depth/frost etc
worst mistake people make in a frost zone on fences is to not go deep enough with the post & mushroom the top portion with concrete . someone once told me it's to shed the water away from the post and makes it last longer... yeah, right.

 

[cdaiscool]

In Ann Arbor, I believe it's 35" down. So for a 6' fence, the link suggesting about 5'4" above ground, I should go 4' down?

And how will I make a bell shape as shown? So a simple post hole digger won't cut it? Pun not intended...

 

[The Cobbler]

this is just my opion, take it for what it's worth.
I do't think belling the bottom is as critical as proper hole depth & not mushrooming the top. I leave concrete about 4 to 6" below grade .
oh, and I'm one of those that pouts the concrete in dry , let the moisture of the earth cure it . never a problem

 

[nolimits76]

There are special drill bits that are bell shaped. But I'm not sure how readily available or cost effective they will be for you.

http://www.finehomebuilding.com/2013/01/10/are-spread-base-footings-worth-the-effort

Reading over this article, it appears they made the hole the max width of the bottom of the bell (in this case 10" diameter). Then used a builder sonotube in the smaller 6" diameter. They talked about using a bag on the bottom of the form to keep the concrete from climbing back up on the side of the sonotube forms.

Guess it makes sense. Probably more economical than other fancy methods.

I'm just having a hard time getting behind the NEED for bell shaped footings. I've seen too many fences constructed locally without bell-shaped footings that aren't problematic. Again, this could be due to my location.

 

[cdaiscool]

My current plan is 2'8" below grade which goes with the 1/3 2/3 rule, and 10" wide to go with the 3.5" wide post.

If I put like 10" of gravel under the post, plus 32" of post/concrete, will that solve the frost line issue?

 

[The Cobbler]

If I put like 10" of gravel under the post, plus 32" of post/concrete, will that solve the frost line issue?

no. probably worse as there is now a space for water to collect & freeze.
fill the hole with concrete and encase your post

 

[cdaiscool]

Looks like it's at 42".

So the post needs to sit on the surface, and concrete around it, no gravel underneath?

 

[ishiboo]

Hey guys. About 2 weeks away from starting a new fence project, thought I'd rack your brains for a minute.

Found metal posts for a decent price at Menard's (https://www.menards.com/main/buildi...tal-fencing/8-post-master/p-1444439143296.htm), going to use those set in Fast Setting Quikrete. Doing a 6' shadowbox, found instructions from Master Halco on how to build it (https://www.masterhalco.com/wp-content/uploads/2017/09/PM-Install-TearPad-011480-English.pdf).

Their instructions are based on 90 deg. angles, but my back yard backs up to someone else's at a 30 and 60 deg. angle. Thoughts how I could overcome this?

I don't think I can swing the cedar stuff, I've heard rumblings about 'cedar tone PT pine' stringers and pickets. Yay? Nay?

Current plan is to put the post 2' 8" into the ground on a several-inch bed of gravel, use the Quikrete to set the posts in a 10" wide hole - post is 3.5" so this should be good?

Finally, anyone know where I can get the post clips they call for? I haven't found them on any sites, don't know if Menard's carries them or what.

Set your posts in gravel. Menards CedarTone *****, it looks nice the first year and by the second year you have to stain it... not worth the cost.

 

[Kevin54]

I installed almost 200' of shadow box fence a couple of years ago. Dig your holes at least three feet, a sack of Sakrete per each hole, post chalked lined out so the post are straight. Wind can't bow that at all.

 

[cdaiscool]

I installed almost 200' of shadow box fence a couple of years ago. Dig your holes at least three feet, a sack of Sakrete per each hole, post chalked lined out so the post are straight. Wind can't bow that at all.

Can I put some gravel under them and the posts at 2'8"?

Otherwise I have to find 9' versions of these or use a different pole.

 

[Jlbc212]

Dig your hole down to the lowest possible expected frost depth. Use sono-tube forms for the concrete. Dump at least one bag worth of mixed concrete into the hole before placing the sono-tube into the hole. Place the metal fence post into the sono-tube. Fill around the metal post with concrete.

 

[LifeLongWNYer]

The actual post holes weren't wider at the bottom, but the concrete was. When installing the posts, the guys had a mixer drive along the fenceline, and drop concrete into the holes so that it was about 6" deep and the full diameter of the hole. The post crew placed a post with a Sonotube over it ( actually they used cut off sections of PVC pipe ) into the hole and set the post plumb. The first crew came back around and filled the interior of the PVC pipe with concrete. On the next day they backfilled the holes, outside of the PVC with the soil removed.

There were several projects like this, for a couple of different clients, all pretty much done in the same manner.



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[Homerr]

...

Their instructions are based on 90 deg. angles, but my back yard backs up to someone else's at a 30 and 60 deg. angle. Thoughts how I could overcome this?

...

Put two posts in at these corners. Extend fence boards over to meet at outer corner. Rip a 2x nailer which goes behind the corner to support the corner intersection.

 

[dsarge84]

Looks like it's at 42".

So the post needs to sit on the surface, and concrete around it, no gravel underneath?

42" is the southeastern Michigan frost line. I would just dig down 48" with a auger and use 10' posts. You can rent a auger pretty cheap from any tool rental and it will save a lot of work. No gravel underneath. Just make the concrete a dry mix and use a long 2X2 to help with concrete consolidation around the post.

 

[cdaiscool]

Put two posts in at these corners. Extend fence boards over to meet at outer corner. Rip a 2x nailer which goes behind the corner to support the corner intersection.

That diagram is perfect, thanks!

42" is the southeastern Michigan frost line. I would just dig down 48" with a auger and use 10' posts. You can rent a auger pretty cheap from any tool rental and it will save a lot of work. No gravel underneath. Just make the concrete a dry mix and use a long 2X2 to help with concrete consolidation around the post.

I have been planning to rent an auger, so that's not a problem.

The Postmaster post is available as a 9', and putting it to the 5' 4" height means I'll be down to 44" down. Being in Ann Arbor, code is 42" down.

I found the 9' at Lowe's Canada, at a store almost 2 hours away, for a bit under $24 USD each. Don't know what import fees will be though.