Back Deck

[DennisFolsom]

When we built our house, in 2004 - 2005, the plan was to put a deck across most of the back side, which faces south. However, due to lack of money, time, and energy, we didn't start the back deck until this year. I did build a very nice front porch deck about 5 years ago.

Photo 1 shows where the deck is going. Note the overhanging portion of the truss roof. The area under the roof will be screened in (approx 8' x 16'). There will be a 12' x 12' section, roughly centered on the atrium door. The middle portion will be approx 8' x 12'. The total length comes out approximately 40'.

Photo 2 shows our old "temporary deck," in the future screened porch area. It was made from an 8' x 4' pallet.

Photo 3 shows our old temporary back step at the atrium door.

Photo 4 shows the area after I had removed the temporary structures, stripped the sod, and placed some of the gravel. The white paint was a preliminary layout of where my precast piers are going. Note the copper flashing over the first ledger board is wrinkled, but is all there. There will be spacers and another ledger board, bolted on, through the spacers, the first ledger board, the rim joist and into backers that I am installing between the joists in the basement. The spacers allow water to drain between the deck and the house.

By putting the first ledgers on before we sided the house, and installing J-channel around them, we avoided having to mess with the siding when we build the deck. However, we made one slight mistake, which I now regret. somehow, the whole thing comes out about 4 inches OVER 40 feet long, which means that my beams, ledger, and rim deck joists will require a 12', a 14', and a 16' piece. For the decking itself, I can get away with two 12' pieces and a 16' piece, because I will be running a transverse piece at the end to hide the end cuts anyway.

More coming in my next post.

 

[jomar215]

People always skimp out of the copper flashing. Well done.

 

[DennisFolsom]

I am using precast concrete piers to support by beck beams. They are 4' tall, 12" square at the bottom, and 6" square on the top. This is the second time I've used these. I also used them on my shed project, which was reported here last fall.

Because my deck will be fairly low, I am not using posts. There will be a bracket bolted to the pier, shims, and then the beam (two 2 x 10's) in the bracket. This method of construction requires that the elevation of my piers is controlled very tightly. I am using a laser level to help with that. In calculating the elevation for the bottom of the piers, I allowed for 1/4" of shim. That way, if I have a pier that is a little high, I am still not out of luck.

I first dig a trench with my backhoe. There are too many rocks here to get away with using a post hole auger. The soil is mostly clay. Fortunately, it is dry enough in this area that I am not getting water running into my holes (like I did on my shed project). My foundation drain has been working for 6 years, which helps the water situation. I set the target on my leveling rod to allow a 4" gravel bed for the pier.

When my hole is deep enough, I reset the leveling target to the bottom elevation of the pier. I very carefully grade and tamp the gravel bed with a rake. My goal is to keep the elevation within 1/8".

I set the pier in with the backhoe, and keep it chained while I start to backfill. I try to keep to all gravel within 6" of the pier, and use the excavated material outside of that radius. In the real world, I'm using a bit more gravel than that. At times, I may also have a bit of clay that comes closer than 6", but that's what I shoot for.

I backfill and tamp by hand for about 1/3 of the way up the pier. Then I take the chain and shackle off and stretch a string (from batter boards) over the top for transverse alignment. My brackets allow a little play here, but they need to be close. Longitudinal placement is not as critical. I put marks on my string as an aid in checking longitudinally, but the marks move, depending how tight you stretch the string. I make any final adjustments in the alignment at this time by leaning the pier in the direction needed and retamping the backfill.

I backfill and some more by hand - to about the 2/3 point - before I fill the top with gravel from the bucket.

Photo 5 was taken after I got the first two piers in.

Photo 6 shows the string stretched over the first row of 4 piers.

Photo 7 shows the first 4 piers and orange X's for digging in the second row of 3. Due to the fact that the first pier in the second row is not far from the last pier in the first row, I decided to make my trenches at a 45 degree angle. This worked out very well. It let me pile my excavation farther out with the backhoe. It also allowed me to place a bucket of gravel on the inside (for hand backfilling) before each dig.

Photo 8 shows how I hook the pier up to the backhoe. The last pier is on the ground in the photo.

Photo 9 shows where I was when I quit yesterday.

As of this writing, I still have one more pier to place. I had to work today at my paying job.

 

[DennisFolsom]

In my previous post, I referred back to my shed moving project. Here's the link to my thread on that one:

http://www.tractorbynet.com/forums/projects/225643-moved-shed.html

Yesterday, before putting the tractor away, I decide to pull out what I thought was a small rock in my back lawn. This rock was a "granite iceberg!" there was a whole lot more of it lurking under the surface. Here's a photo of it after I loosened it up, and one showing it in the bucket.

 

[ustmd]

Looks like it is going to be a great deck.

I am impress with your ability to keep the piers on level and in line with the back fill. Are you worried about settling affecting the alignment?

 

[DennisFolsom]

Looks like it is going to be a great deck.

I am impress with your ability to keep the piers on level and in line with the back fill. Are you worried about settling affecting the alignment?

The original clay soil under the excavation is hard-packed and it is down about 3.5 ft. Especially on the south side, and near my semi-heated basement foundation, I don't expect to have frost trouble. I tamped my 4" bed of 1.5" gravel quite well. I still possibly could get a bit of setttlement, but I don't expect much. If I do have a problem, I can unscrew the brackets on the beams and re-shim them.

Thanks for your comment and interest.

 

[DennisFolsom]

This afternoon and evening, I got the 7th (and last) pier in. Here are a couple of photos.

Next, I plan to shape my gravel, put plastic down and cover it with more gravel.

If it fits with my work schedule tomorrow, I'll meet with the sales rep from my lumber company and finalize the order for the framing lumber. If all goes well, we should be framing this weekend.

 

[jomar215]

Unsolicited opinion: (isn't that what makes TractorByNet great, the unsolicited opinions ... anyway) may I suggest landscape fabric over plastic? The plastic will be basically tatters within 3-5 years whereas the fabric will still be there. It's more expensive but longer lasting, and it doesn't seem like your skimping. Also, and don't tell anyone I said so, but a little motor oil around the outside of your piers will keep the frost from heaving 'em. If you have frost wherever you are and all the other appropriate disclaimers included.

Just saying .....

 

[DennisFolsom]

jomar215 -
Thanks for the advice. I always appreciate getting advice and opinions, whether I use them or not.

The tapered design of the piers is supposed to keep the frost from grabbing the sides of them. A little lubrication probably wouldn't hurt, though.

I bought 6 mil plastic. My thinking was that water goes through the landscaping fabric, and I'm trying to get the water away from the foundation as much as I can. I plan to slope the gravel away, lay the plastic, and put a couple more inches of gravel on top of the plastic. I'm only talking about the area under the deck. If I have plastic extending beyond the deck (and I may), I will cover it with more gravel. Hopefully, the plastic will last that way.

We have some thinner plastic (garbage bags actually), that's been down for 5 years, covered with flat rocks and stone dust in the cracks. I dug into the end of those and they seem to be holding up OK.

We did use some landscaping fabric on an area that we mulched over and planted shrubs in. In that case, we wanted the water to go through, but wanted to keep the weeds down. That has worked well for a couple of years, now.

 

[jomar215]

Yeah, I have seen thos plastic bags like you would wrap your produce in at the grocery store last a long, long time without much sign of wear. But then, I've used that same 6 mil as tarps and seen it gone in 1 year of being baked in the sun. I've dug up the same plastic a year or 2 later and it was pretty well gone, too, but not quite as bad as the sun baked portion.

If you want to get the water back I'd just slope the surface, presuming you've got some clay in your soil we do around here, away from the house and pack it down but good. Cover it with a good drainage stone and it'll drain. The ground might become saturated some in real heavy storms. They say a level pipe will drain, and it will, but code only calls for 1/4" of drop in 10' of run. If you can put 2" of pitch over 8'-10' you won't see too much water accumulate.

Do you get water in your basement? Is that the problem?