Deck building questions

[Brian Hale]

We're laying out our deck and can't settle the footing debate. Which is better... Putting the post on top of a concrete pier dug into the ground or (the way i done it in the past) dig the hole, fill the bottom with ~10" of concrete, set post on the concrete and fill the hole with fresh concrete?

At it's highest point, the deck surface will be ~40" above the ground.
Size is 25' x 50'

I found it eaiser the second way but she wants the first way...

Help!

Brian :)

[Jason Roehl]

We're laying out our deck and can't settle the footing debate. Which is better... Putting the post on top of a concrete pier dug into the ground or (the way i done it in the past) dig the hole, fill the bottom with ~10" of concrete, set post on the concrete and fill the hole with fresh concrete?



Better is definitely putting the post on top of the concrete above ground. Encasing wood in concrete pretty much guarantees rot, even PT lumber. The problem is that the wood will shrink away from the concrete after construction, leaving a small gap that will trap water against the wood for long periods of time.

Please note that the posts setting on concrete above ground have to be anchored to the concrete somehow.

[Brian Hale]

Better is definitely putting the post on top of the concrete above ground. Encasing wood in concrete pretty much guarantees rot, even PT lumber. The problem is that the wood will shrink away from the concrete after construction, leaving a small gap that will trap water against the wood for long periods of time.

Please note that the posts setting on concrete above ground have to be anchored to the concrete somehow.

Thanks Jason

I hadn't considered the wood shrinking but your correct. I've built 11 decks in my younger years and all had the posts set in concrete in the ground with the concrete ~6" above the dirt. Hope i don't hear anything bad about them...

How long will PT wood last?

Brian

[Jim Becker]

Concrete footing to the surface with embedded J-bolt. Metal bracket to hold post off the concrete fastened to embedded bolt. Post in the bracket to support the deck. This method minimizes water issues with wicking and also makes adjusting or replacing the post in the future much easier. This is actually the method required in many areas these days.

The depth of the concrete footer is geography/climate dependent.

[Michael Perata]

Concrete footing to the surface with embedded J-bolt. Metal bracket to hold post off the concrete fastened to embedded bolt. Post in the bracket to support the deck. This method minimizes water issues with wicking and also makes adjusting or replacing the post in the future much easier. This is actually the method required in many areas these days.

The depth of the concrete footer is geography/climate dependent.
http://www.strongtie.com/products/categories/post_bases.html

[Tom Peterson]

I found that the first way was easier because you set a flat datum to build off of. I used Hilti anchors and brackets to keep the P.T. off the concrete surface. Setting heights was easy, and no worry of rot from the conrete to wood contact area

[Bruce Shiverdecker]

We're laying out our deck and can't settle the footing debate. Which is better... Putting the post on top of a concrete pier dug into the ground or (the way i done it in the past) dig the hole, fill the bottom with ~10" of concrete, set post on the concrete and fill the hole with fresh concrete?

At it's highest point, the deck surface will be ~40" above the ground.
Size is 25' x 50'

I found it eaiser the second way but she wants the first way...

Help!

Brian :)

Evenin" Brian:

I a thought. You mentioned using 10" of concrete for the piling. I don't know where your frost line is or if you have one, but here in central Illinois, that line is at 43" below grade, so we have to dig at least 44" down for our footings; even for decks. If we don't, they will be thrust up over time by the frost. I also agree that using a bolted bracket to hold the uprights on top of the piller is best.

Good luck with your project.

Bruce

[Frank Pellow]

I have had good results with the dig the hole, pour a base, put in the post, then fill around the post with concrete method. The posts afor my deck are buried 4 feet into the ground. The concrete extended about 6" above the ground.

The main reason I did it this way is that I wanted some of the post to extend about 10 feet above the ground (about 8 ft above the deck level) to support a fence. The posts that I used were 4 x 4 western red cedar and I soaked the part that was to be in the ground for about a month in creasote before using them.

This was 23 years ago. Last week, I had to saw off 3 of the posts at ground level in order to make room for my new work shop and they were all very solid with no rot.