I’m in the San Francisco bay area, and we have been having a LOT of rain lately. the ground is saturated, and I have somebody asking about doing a small fence and pergola. Is the ground too wet to dig and set posts? When it dries will the earth not hold the concrete? I’m guessing it won’t be a problem, but feedback would be welcome. Frost line is not an issue, because we don’t have one. Also, I’ve heard and seen several ways to set posts, from encasing them in concrete to setting them on a bed of gravel and backfilling with concrete, and using metal holddown/anchors (Simpson Strong-tie to the rescue). What’s the best? It’s just a 3′ fence and very open, and Heart B Redwood. They prefer not to be looking at the steel hardware. Thanks
Young, poor, and eager to learn
Replies
The ground is too wet to be digging in now, suggest you wait till the ground can be walked on without mud up to your ankles as a result. The fence part; Use pressure treated posts not redwood. Dig hole, install post and add concrete. Go to 2 feet depth before installing post regardless of fence height ( Assume fence not over eight feet in height).
For others, strongly suggest use Sonna Tubes (spelling) and pore concrete with Simpson post anchors above ground plane by about 3 inches then install posts. Again, I would use pressure treated lumber but redwood (clear heart) would probably be sufficient.
When you do the fence you'll need a 3 foot level to plumb the posts. Put in the first and last posts to start, once plumb then pull a string line between the two and set your intermediate posts the same way.
If you've never worked on setting fence posts plum with a level then I strongly suggest you attempt it first in your back yard a couple of times to get the technique down before you start. Also, just digging the hole to two foot depth is harder than you might expect. You'll need, at a minimum, a shovel and digging bar. The best tool I use is a Bosch demo hammer with spade bit to dig the holes. Because you stated that your young and poor, get the shovel and digging bar before you start. Without digging bar you will never get the job done in a timely manner, again strongly suggest you attempt to dig hole to two foot depth with the proper tools. You can use two stakes to plumb the post or you can do it without which is faster. Dig hole, install post and add half shovel of dirt with one or two small rocks in it around the post. Use the level at this point and then with the handle of the shovel, tamp the dirt all the way around the bottom end of the post. This will hold the post in position temporarily then check for plumb. To move post one way or the other just add a small amount of additional soil on that side of the post and tamp with the end of the shovel handle. Once plumb, carefully add concrete and recheck for plumb. If off then add a rock or two to the weak side and tamp again till plumb.
Practice makes perfect.
One more thing, don't make the hole more than just a couple of inches bigger in diameter than the post because you'll have nothing but problems if you do.
Get some gloves too to keep from getting blisters.
I don't think I'd bother with concrete as frost is not an issue.
Spend the $ on a couple extra feet of lumber. Dig down about three feet....larger stones at the base, maybe some pea gravel surrounding the sides.
Good luck.
J. D. Reynolds
Home Improvements
Pea gravel on the sides won't hold. You need fractured rock so it will interlock and resist lateral force. It's still able to settle as the ground dries and shrinks so it will keep the post tight (though it may need an occasional tamping initially).
If ignorance is bliss why aren't more people
happy?
If you go with redwood instead of pressure treated, soak the part that goes in the ground in Jasco Termin-8. IMHO, it's at least as good as PT.
-- J.S.
better.....Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!<!----><!---->
Forget the primal scream, just ROAR!!!
You wouldn't happen to be Irish would you? Just got this months issue of FH (May 2006 # 178) and you won't believe what's on the front cover. Inside they describe a step by step method how to build a Pergola. You said you don't want the post base to show...use 6 x 6 post but get 4 x 4 post base and cut slots in base of each post to fit over the thin metal ears of the post base and all you have is the bolts showing. Of course you would have to predrill the holes with a pattern of the post base but with some wood plugs and ingenuity you could cover those too.
They copied my sonna tube (spelling) suggestion too those low lifes.
I've done a few heart redwood posts in a fence and they just don't last below ground. Maybe the suggestion of using Jasco's stuff would work but I can't say for sure, I'll have to give it a try. Touble is I won't know for 10 to 15 years from now and then I probably won't care either. If it doesn't then just be sure your not around when the post rots off at ground level.
Thanks for the input folks...Yes, I am part Irish, but I didn't get the connection. I've dug plenty of post holes in the past, so that doesn't bother me, especially since I won't be digging these. I appreciate knowing about Termin-8...The only other name I knew was CopperGreen, and it looked like the Jasco had more active ingredient, so I'll probably go with that. The whole system will be Redwood Clear heart, and I really (hopefully) have little to do with the project, because I just don't have time. I think I convinced them to beef up the structure of it though. I didn't like the previous design.
However, on a side note, I was hoping to get input more on the setting of posts in concrete, if and when necessary...I've done it before by order of other people, and they really encase the post in concrete. I've also heard of putting in a few inches of gravel to allow for drainage, then post, then concrete around it (this would leave the bottom of the post without concrete, just to be clear). Just wondering how other people do it.
Thanks again
Young, poor, and eager to learn
I'm in the Bay Area also and one thing you might look into, that I used, are stained pressure treated posts. They are a good match for redwood and cedar, and after one season, I can't tell the difference. I got mine at an Economy Lumber Mike
Trust in God, but row away from the rocks.
Irish, as in Luck of the Irish. You are lucky because FH just came out with issue instructions on how to build a pergola.
Dig your post hole and bury 3 of the 8 foot pressure treated post, in concrete.
Assure they are all spaced 8' apart and are on the same string line and are plumb.
Let them sit for a day or so and than hit it hard with the entire crewl
Grunge on.
skip the concrete and use gravel instead...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
I'd use nothing but a piledriver and drive the posts in, start with an 8ft 4x4 (for your 3ft fence) my pile-driver is nothing more than a 28" long 6x6 sq steel tube with 3/4" steel plate on one end and 2 loop handles running down 2 sides (it's actually the bottom 28" of a small exxon sign post with the handles welded on) do not cut the end going into the ground into any type point... blunt is good... you might need a little help and might need to stand on something like a drywall bench to get them started into the ground... you'll know when to quit drive'n em in...ie you get to desired height or they just aren't go'n in any further.. last step is to cut the leftover off... i can drive posts and be building the fence while you are still digging holes...
end result IMHO is much better than digging a big hole that you just have to refill with something..ie concrete.... I started doing this on fences after i drove the piles for my dock and boathouse expansion reading that undisturbed soil is much better and side friction is usually as important as whatever a post/pile bears on...
p
Yep, ya gotta wait. Now they are calling for at least 2 more weeks of it, another storm every 48 hours - ARGH!!! Told my folks I'd replace their mailbox post if it ever dries out.
Speaking of my folks... Fences on 3 sides of their yard, all installed ~ 1955, all redwood (yea, I know, can't get that kind of wood any more). Two of the sides were replaced a few years ago. About a third of the fence boards were salvagable but only a few of the posts. 48 years ain't too bad. Those posts were placed on gravel + ~6" on the sides for drainage, with concrete to grade. If you encase the post completely it will shrink, water will get in and rot the post from the bottom cause the water can't get out.
The third fence has no concrete at all - just dirt tamped well. Still rock solid. You can draw your own conclusions. (Oh yea, that's how PG&E does their power poles as well...)
The Simpson brackets state that they are not designed for free-standing strcutures like a straight fence.
Depth - 2' is usually fine for a 6' fence; I go 3' for gate posts. Of course the big disclaimer - "it all depends". ponytl can use his post driver because of his soil. I'd love to see him get more than 6" in the "soil" I have (heavy clay halfway to becoming stone). Same deal with digging bar. Although my soil is tough I can dig it with a clamshell type posthole digger. On other Bay Area sites I've needed the digging bar or a jackhammer. Your milage may vary. Type of soil will also determing how deep ya gotta go.
If the soil's that wet then concrete will work loose fairly quickly as the ground dries and shrinks. Also, the concrete will cause wood posts to rot quickly. Backfilling with crushed rock is probably better, or use some sort of screw-in anchor.
happy?