Features

Good posts can make or break a deck

By James and Morris Carey The Associated Press
Friday August 02, 2002

Our remodeling company recently was called to repair a leaking second-story deck. The deck is located on the windward side of the house and leaks were showing up at adjacent interior walls and ceilings. 

We had to remove a lot of surrounding surface material in hopes of eliminating existing fungus damage. Leaks in tile decks can be disastrous to surrounding areas and are costly to fix. Since the deck was going to be finished with ceramic tile, the deck-post system suddenly became an extremely important consideration. We didn’t want the posts to come up through the flooring because each penetration would eventually become a potential leak hazard. 

The tile detail extended over the edge of the deck in the same fashion as a countertop. This made connecting the posts even more difficult. We didn’t want them to penetrate the edge of the tile either. This meant we couldn’t bolt the posts directly to the side of the deck. What were we to do? 

Since there was plenty of bolting area beneath the tile edge, we decided to use thicker-than-normal posts and notch them at the tile edge. We, thus, were able to achieve a strong connection through heavy bolting at the deck perimeter. And, we did not have to worry about penetrating the waterproof surface anywhere. 

Amazing, isn’t it? Even a deck-post connection can be important. Also, how a post is connected to a deck can have a great deal to do with the deck’s appearance and how strong the hand rail is or isn’t. We like to notch the post so that the rail system is centered over the edge of the deck. Also, we prefer the strength of a two-post corner system where others suggest that a single-post system is cleaner. We also prefer to use 4x6 posts instead of 4x4’s. Once the post is notched, its depth at the thinnest point is not less than 3 1/2 inches (a full 4x4). 

We also like to use vertical grain, clear-dry redwood when the budget allows because the material can be pre-stained before assembly (no waiting for natural moisture to evaporate). Also, clear material is stronger than the same material with knots, and vertical grain is simply the most beautiful wood in the world to behold. 

We recently decided to begin using neoprene washers at the bolt connections between the post and the deck edge. The washers act as spacers between the post and the deck and guarantee a free flow of air at the connection. We have found that wherever wood connects there is a chance for rot. All such connections have a tendency to hold enough moisture to promote rot. 

In past columns we’ve mentioned the under-board deck-fastening system. This is another step in reducing rot and lengthening the life of your deck. When it comes to bolt connections, size is extremely important. Each post should be connected to the deck with at least two half-inch through-bolts, with the spacers we mentioned and malleable washers (the big, square kind) at both sides. Through-bolting is important because it easily can be tightened later as the wood expands and contracts. 

Our customer’s deck already had a beautiful plywood soffit (ceiling cover). This meant that we wouldn’t be able to gain access to the deck framing later on. We were forced to use lag bolts. We used large chunks of 4x6 blocking as backing for our lags. One thing we didn’t want to do is remove plywood siding to tighten bolts — kind of an expensive process. Spacing between parts in open-rail systems is important. There should never be more than 4 inches of clearance between any parts. Be careful here, some building departments require the space to be even less. Check with your local building official before beginning. 

Deck rails should not be less than 36 inches above the deck. Your building department might require 42 inches. Be sure to check. 

We just discovered that Consumer Reports says that clear finishes don’t work on decks. They tell us that the clear materials just don’t hold up. We always have disliked using paint — too much maintenance. Consumer Reports Magazine seems to agree, stating that Cabot Stain is their No.1 choice. Whatever you choose, make sure that your finish coat is oil-based and of high quality. 

For more home improvement tips and information visit our Web site at www.onthehouse.com. 

 

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