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Detecting Dry Rot: An Interview with David Lucas of Details of Sonoma

By David Lucas

It is very appropriate to introduce Details of Sonoma, Inc. with a discussion of "Dry Rot". Dry Rot played a big part in my own story and helped shape my company. Back in 2004 I was laid off after 10 years of service Agilent Technologies / Hewlett-Packard. It wasn't long before I found myself helping a friend with his handyman business. Within six months, we had outgrown the confines of a handyman business. My partner and I decided to design Details of Sonoma (Details). Having great respect for and experience doing things the HP way; I decided to use that business model for Details. What drove the early design for Details was a strong desire to build a company that would last, and be highly. Within six months, we were incorporated, licensed, bonded and insured. A freshly minted contracting company.

It's right and good to strive for excellence, but until a reputation is established no one knows who you really are and if you can be trusted. We were blessed with great clients who gave us a chance and we didn't let them down. So for the first year and one half, we found and fixed "Dry Rot", lots and lots of it. We learned firsthand just about every wrong way previous contractors can and did built things that failed.

Our work on Dry Rot was important in shaping our business for these reasons: First, Dry Rot is ugly and very destructive. As craftsmen we want to do good work and have it last. There is real pride to be had in doing great work that will endure for decades. We didn't want our hard work to be wiped out by Dry Rot. We started to pay attention on how the Dry Rot problems were created. We didn't want to repeat these mistakes. Dry Rot has three main causes: poor design of a building, poor construction techniques or execution and poorly painted buildings. So now when we build, we will work with the owners to improve design, use best practices and materials. To top it off we have our own high quality paint company inside Details so all our hard work is always properly protected.

So what is Dry Rot and why is it called Dry Rot anyway. Dry Rot is an old English term that goes back hundreds of years. Dry Rot is an organic process of nature reclaiming wood and decomposing it. It goes on all the time in forests and on wood left unprotected. We live in a world covered with fungal spores. They are the means by which Dry Rot is spread. When wood is exposed to high levels of moisture (20% to 30% by weight or higher) the naturally occurring spores start to grow. And if conditions persist they will form a white lacy film called mycelium over and in the wood and if left alone long enough they will destroy the wood they infect. Even if the wood dries out for a time the rot will continue when the moisture returns.

A home or building is made of many parts but for this discussion it is useful to think of the framing of a house (plates, studs, floor joists, rafters, headers and shear) as the skeletal structure of the home and the outer coverings (roofing, siding, door and window trim, windows) is like the skin of our bodies but for the home. And just like human skin the siding is there to protect the body from infection.
If we go back to the causes of Dry Rot the first thing is that the trim and siding of a home need to be kept dry. Dry wood doesn't rot. So why not just wrap the house in plastic. Well aside from being unsightly plastic would trap water inside the house and the same thing would happen.
The building protective layers need to keep water from rain and fog out but they also need to be permeable and let moisture from people out. Humans, cats, dogs, house plants, dishwashing, cooking, bathing all put moisture in the air and that moisture needs to get out. Most houses handle interior moisture well.
Architects and Designers like to dress up a house with trim. But when trim is placed on a house it must be made from the right materials and sealed with high quality, primer, caulk and paint; and in that order. The most common causes of Dry Rot is poor quality materials put on improperly and not sealed correctly. You may have heard of the term SPF in connection with building trim. This stands for Spruce, Pine and Fir - these are softwood. None of these woods have any real rot resistance.
The building industry has come up with many wonderful products to combat Dry Rot. Products like cement fiber siding and trim (Hardie, Nichiha and others), Cellular PVC trim and panels from AZEK is great, and natural products like Cedar all resist or are impervious to Dry Rot. Louisiana Pacific now has siding product with a 5 year material and labor warranty and a 50 material warranty.
Lowest cost grade of trim is called Clear Cedar Re-sawn Finger Jointed or CCRFJ. This is a product that performs wonderfully.
The decking industry is also undergoing a huge transformation with all kinds of new deck materials. One of the most exciting decking options we have found and a new venture we are now launching is the all tile deck. We are just starting a company under Details called the whole structure is steel, concrete and tile. We are exploring the idea of a lifetime warranty and we think these decks are a real solution to problem of Dry Rot in decks that need maintenance. Tile decks offer the promise of zero maintenance.
So where does the term Dry Rot come from? When the whaling fleet was put in dry dock for the winter the hull would start to dry and with the moisture content of the wood less than 100% and greater than 25% the hull would quickly dry and appear to rot when it was out of the water and dry.
You can recognize Dry Rot by sight and by feel. It will make the siding look shriveled, sunken or hollowed out. In extreme cases it will crumble. If think you have Dry Rot take a key or pocket knife and press it into the suspected Dry Rot. If the wood is rotten it will be soft and your tool will sink into the wood. Health wood will be firm and hard.

To treat Dry Rot, you must remove the damaged wood and replace them with new wood. In extreme cases this will involve removing trim, siding and framing. If you think your home has Dry Rot please have a licensed contractor look at your home. When replacing Dry Rotted parts the items you put back should be made from rot resistive materials, if possible, like Cedar, fiber cement or Cellular PVC. The only exception to this is for framing you need to use Doug Fir lumber for framing. Cedar is not strong enough. You need a contractor who knows how to correct these problems and build correctly so that your home doesn't experience this kind of problem. And finally you need to paint your home and do the paint job that will actually protect your home. To paint your normal home it takes a crew about a week of work and that is, if the home is in good shape. If it's damaged and needs lots of TLC you should expect the effort to two or three weeks. We offer paint jobs on single family detached homes that carry a lifetime warranty. They take a lot of effort to execute but a home with great siding and trim can be painted so it lasts and lasts.

Our web site is you can check us out and see how we do what we do. Our clients are very happy with our work and we take a great deal of pleasure from each job being a job well done.


David Lucas
Details of Sonoma, Inc.

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