Volume 46, Issue 5 - June 2007

Ask Shelter
experts address important questions

All Cracked Up
Expert Addresses Preventing Deck Decay

When customers have questions about sealing their outdoor deck, you need to be prepared to answer the questions. To help answer some deck sealing questions, Shelter turned to Huck DeVenzio, manager of product information, Arch Wood Protection, the licensor of the production of Wolmanized® wood products.

Q: A consumer’s deck is deteriorating. What’s the most economical solution for preventing further decay?

DeVenzio: Properly treated wood has long-lasting protection against damage from termites and fungal decay and the best brands carry a limited warranty that extends for the lifetime of the purchaser. If termites or rot are the problem, the consumer can probably place a claim with the warrantor for replacement material.

More likely, the deterioration is a result of moisture damage, which may show itself as cracking, warping or raised grain. These tendencies are not covered by warranties and are nearly impossible to repair. There is no good way to un-crack wood. However, further deterioration can be minimized by applying water repellent, often called sealant, every year or so. Water repellents do not really seal the wood’s surface, but they slow down the rate at which moisture is absorbed and released, thus reducing swelling, shrinking, cracking and warping.

Q: Does a new deck need to be treated? Or can a homeowner wait several years, since the wood is pressure treated already?

DeVenzio: Preserved wood that meets industry standards needs no subsequent treatment to withstand termites or fungal decay; this wood should remain structurally sound for decades without any maintenance. But, for deck platforms, railings and surfaces that homeowners want to look good for a long time, the regular application of a water repellent coating is highly recommended. Occasional cleaning with a deck brightener and regular spraying with water repellent will have aesthetic benefits.

A common question among homeowners building a new deck is: “How long must I wait before applying a coating?” 

The answer is not as simple as it once was, because there are now more options in treated wood and in coatings than previously existed. Some treated wood is sold in a damp condition, still wet from the treating process; some treated wood is re-dried after treatment to remove moisture, and some contains built-in water repellent as part of its treatment. In addition, some coatings are water-based and others are oil-based, and some form a film while others penetrate. The main reason for waiting is to allow excess moisture to escape from the wood before applying a barrier coating such as paint. 

In short, unless the wood was re-dried after treatment, it is best to wait at least six months before painting. Stains usually do not require a delay, unless the wood contains water repellent and the stain is water-based. In all cases, the directions of the coating manufacturer should be followed.

Q: What can a dealer do to help customers avoid or postpone deck deterioration?

DeVenzio: The best way to forestall moisture deterioration is by fortifying wood with the defense it needs. Dealers should recommend periodic use of water repellent coatings to contractors and homeowners. This is good advice as well as a sales opportunity. A dealer should also consider stocking treated wood of better quality—that is, wood of a higher grade, wood that contains water repellent and wood that is kiln-dried or air-dried after treatment. Each of these features adds cost to basic treated wood, but they provide customer-pleasing properties and still result in a cost lower than that of artificial wood decking. Homeowners get the attractive appearance of real wood, and they get better long-term performance. Meanwhile, dealers are likely to benefit from fewer exchanges and a better reputation. 

 


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