Upgrading a Deck

At first glance, this 20-year-old New England deck looked to be in reasonably good shape, thanks to regular maintenance.

But a closer inspection of the deck revealed a number of problems, including PT deck boards that were checking and spitting—not exactly a foot-friendly walking surface.

Fastener corrosion can also be a problem in older decks. Here the nail shanks had rusted through, allowing the decking to lift away from the framing.

Held together with finish nails, the railing wasn't strong enough to meet code. The balusters were too far apart, too, with 8-inch instead of code-maximum 4-inch gaps between balusters.

Finish nails were also used to fasten the rails to the posts.

Notching a 4x4 post to fit into a corner seriously compromises the strength of the post.

On a low-level deck like this, the best way to assess the ledger-to-house connection is to remove the first few courses of decking.

When I removed three deck boards closest to the house to start working on the ledger, I found a series of old beer cans, perhaps an indication of how seriously the original deck builders took their workmanship.

The ledger was connected to the house through the skirt board with a few lag screws and some nails. Note the absence of any ledger flashing.

The clapboards above the ledger had to be carefully pried away from the siding so the author could install new flashing.

We fabricated aluminum L-flashing with a 5 ½-inch-tall wall leg—the tallest it could be without bumping up against the nails on the overlying siding course—and a 3-inch-wide joist leg. Along the edge of the joist leg, we bent a reverse hem to stiffen the metal and make it easier to handle when slipping it into place.

It was also necessary to remove the riser boards under the doors in order to slide the aluminum flashing into place.

The ledger connection was reinforced with pairs of 5-inch-long LedgerLOK screws in each joist bay. The lower screws were carefully pre-drilled so that they would penetrate the center of the mudsill.

Since only one ply of the double rim beam was fully supported by the notched 4x4 support posts, short 2x4 blocks were installed between the top of the footings (which were about an inch below grade) and the outside beam ply.

The original joist hangers were still in good shape, but only nailed in place with a few roofing nails. The author replaced the undersized nails with structural metal connector screws.

Every hole in a metal hanger should be filled with a correctly sized fastener.

Angle brackets were used to reinforce the connection between the ledger and rim beam and the end joists.

Retrofit metal hardware was used to reinforce the connections between the posts and rim beam.

Metal connectors are designed for specific framing details and sized for specific framing dimensions, and shouldn't be modified in the field.

The new 4x4 guard posts were unnotched, and were attached to the framing using a combination of Simpson Strongtie DTT2Z connectors and the appropriate blocking detail for each location.

Guard-post connection details depend on where the post is located relative to the deck joists. Here, ThruLOK fasteners were used to attach the post to the double rim joist, while DTT2Z connectors reinforce the rim-to-joist connection.

Along the sides of the deck, where the rim joist runs parallel to the deck joists, threaded rod is used to tie the guard posts to blocking installed between the joists.

Some 2-by blocking had to be planed down prior to installation in order to get this stair post in the right location.

The old stained rim board is covered with Earthwood Evolutions fascia to dress up the perimeter of the deck. Flexible flashing covers the joint between the rim joist and the fascia, which is installed over blocking.

Prior to installation of the new decking, strips of flexible flashing tape were stapled to the tops of the framing to protect the wood from water and debris.

The new TimberTech Earthwoods Evolutions Terrain decking was installed with HIDFast stainless hidden fasteners.

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