On the Level: Knowing what's best for maintaining your deck

I am in the process of getting my house ready to sell. It seems to be a male thing, but I keep getting advice about power-washing my deck and putting down a sealer. I've never done either and will follow your advice about using a pressure washer on wood. I don't like the look of stain for decks, even though my house is cedar and stained. I prefer the "natural" look and don't like to use any more chemicals than necessary. The expense also is another factor. Can I say Jim Rooney says it's not a good idea? So far, I've just said "I've heard it's not good to use pressure-washing" and my friends just look at me. I was told in one of your recent articles that you had a homemade recipe for deck cleaning. Could you please give me the recipe for the cleaner?

Also I've read about a deck that fell down with about eight people on it causing injuries. My house is the same age as the house with the falling deck, and I wasn't the owner when mine was built. Is there a way I can tell if my deck is safe?

A great many of the decks that hang off the backs of houses in this country were added after the house was built and after the local building inspector had come and gone for the last time. Either the homeowners decided to build the decks themselves or they hired someone to do it, but the bottom line is that the whole project went ahead without any third party supervision. The safety and structural integrity of those decks was a pure roll of the dice and depended completely upon the skill and experience of whomever did the work. As you can imagine, this is a recipe for disaster. The worst that I recall was out in Chicago a few years ago where a three-story deck built without a permit collapsed with loss of life plus serious injury. That was unnecessary to the point of criminal.

The weak point of old or unpermitted deck construction is in its attachment to the house and lateral stability. In the old days the deck framers used to just nail the house side band-board - the board into which the deck joists perpendicular to the house will be attached - into the rim-joist - the corresponding framing member of the house. The ability of this arrangement to work depended upon the size of the nails and the number used and at best wasn't a dependable connection should the deck ever become "loaded" to design loads. Design floor load of a house is forty pounds per square foot of area and a 12' x 10' deck's design load is 4,800 lbs or the curb weight of a Hummer H3. It's true that most floor systems don't get loaded to design load regularly but the deck nails gradually start to pull out until that crucial moment arrives and down it goes. Decks built against homes with manufactured truss type floor joists present a whole different set of deck attachment problems.

Building codes in the 1970's began requiring bolting the decks to the house at ever closer intervals until the whole notion of relying on the strength and redundancy of those bolts was wisely deemed too unreliable. Now if you were to construct a deck using current requirements the deck would be a freestanding structure with bearing down to the ground at least at all four corners and more as the size increases. Properly constructed decks are now so strong that the house could fall down and the deck would still be siting there and the Hummer could still sit on it. If you don't know the pedigree and history of your deck you'd be wise to check it out. Crawl under the deck and look for bolts - if you don't at least see that then call a private inspector or deck contractor out and make the appropriate changes as needed to keep your deck where it is. Tell prospective buyers about it, too.

The deck washing recipe is simple. I pass it out a lot so my apologies to those who have heard it over and over from me. You can buy a deck wash at a hardware store but this one is free because you probably have the ingredients already. Wash the deck with a mixture of 1 cup laundry bleach plus 1/4 cup automatic dishwasher detergent to a gallon of hot water. Scrub on with a plastic bristle brush. Scrub well. Wait until it's almost dry then hose off. Wait a dry week then seal. Works on roofs and siding as well. You'll see many cleaning recipes similar to this one and they always say to include TSP (tri-sodium phosphate). You'll buy a box of TSP and never in your life use it all. TSP in a component of dishwasher detergent so using it is a cheap and easy way to get what you need.

Power washers in the hand of an inexperienced user can cause damage to the deck, and I don't like the words power and wash used at the same time. They are fun to use and the damage doesn't show up until the deck has dried and suddenly the deck looks like it has grown a fuzz - that's splintered wood caused by the power of the stream of water. The recipe above is all you need and the power from a garden hose is all the wash power you'll need.

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