Installing the Deck

I was dreading the actual process of digging and installing the deck because previous backyard projects have taught me that the land here is very hard to work — it is a thin layer of landfill rich with large rocks, on top of a solid layer of bedrock. Drilling post holes and renovating the sun deck have been major chores because of this.

I briefly considered using surface-mount technology for the deck footings (“deck-blok” blocks that sit on the ground and support wooden posts) but rejected it for several reasons

• They’re visible and unattractive, and I’m trying to keep this project looking nice;
• There is some possibility of horizontal shifting, or vertical heaving. This wouldn’t worry me too much for the deck itself, but
  • I would worry about a deformed deck contacting the central pier; and
  • I would worry about a deformed deck stressing the fastened-on observatory dome.
• In any case the technology would be unsuitable for the central pier, which requires excavation.

Eventually I decided to get commercial help. We had an excellent contractor (K-Deck) do a deck renovation for us last year, and were delighted with his workmanship and his price. I discussed the project with owner Mike, and he agreed to give me three quotes, in increasing order of price:

• Doing the excavation and installation of 5 concrete footings (4 corners and central pier); and
• Concrete central pier footing and constructing the deck with surface-mount blocks; and
• Full and proper job, with concrete central pier footing and constructing the deck with concrete footings.

I fully expected to choose the first option, doing the carpentry myself. However, Mike surprised me with a quoted price that was substantially less than I had predicted, and I decided to get him to do the whole job. I’m glad I did — it is clearly hard work, and he has done a great job — better than I could have done.

I patrolled the yard at night, locating the best spot for the pier — defined as the position from which I could see the most sky in every direction. I marked this spot with a bright orange tent peg, then marked the outline of the rest of the deck around it, using the dimensions already calculated.

The K-deck crew then stripped the sod and excavated the 5 footing holes. They’re shown covered with wood here at the end of a work day, to keep the dogs from falling in.

The excavation involved removing a lot of big boulders.

And each hole stops at solid bedrock, about one metre down.

Approximate-length Sonotubes are being test-fitted into the holes.

Then the bedrock was drilled in each hole, and each had a length of steel reinforcing rod driven into the rock.

K-Deck owner Mike and helpers, here checking the level of the footings.

After levelling and positioning carefully, they backfilled around the forms so they are held in place by earth. Vertical posts for the 4 deck corners are also in place here.

Now all the forms are filled with concrete. The 4 corner forms are filled to pre-marked lines where they are all the same absolute height (not the same height in the tube, since the ground isn’t level).

The central pier is filled all the way to the top. (Filling is not complete in this photo.)

Then the prepared J-Bolt form was placed into the concrete, with the J-Bolts buried in the wet concrete.

Here Mike is carefully checking the level of the J-Bolt form, which ensures the J-Bolts will be vertical.

He also checked and adjusted the 4 corner posts to ensure they were vertical.

Then everything was left for the concrete to cure.

A quick check by the concrete inspectors, and we are all set to leave the site for the night.

After installing joists on the corner footings, a layer of screen is installed to reduce insects entering the observatory by coming up through the openings between the surface planks.

Then the surface planking is installed over the screen.

The actual construction of the cedar deck took only a day. Beautiful work, in Western Red Cedar.

In this photo you can see the concrete top of the central pier footing, flush with the deck surface.

And another final check by the Deck Inspector finishes off this day.