Does Exotic Deck Wood Ever Rot?

A Cautionary Tale of Rot and Restoration

It happens.

One of the biggest myths about exotic deck woods is that they never rot.

It’s not something we see every day, but it does happen.

All wood is capable of rotting.

That’s what keeps it interesting.

A handful of contributing factors have to converge for exotic deck wood to rot, and about a decade of time.

Here are some of the issues that brought this one down:

• wasn’t pre-finished on all sides
• less than ideal flashing detail
• standing seam roof dumping water, snow and ice on it
• full sun exposure
• lack of proper maintenance

The deck in this case study is not IPE, it is a close cousin: red meranti, a very dense Philippine mahogany.

Extreme Maintenance

This deck was not only visually unappealing, it was unsafe. The thought of anyone stepping through a deck is just not ok.

The homeowner was pretty sure that the entire deck, 14 years old, should just be removed and replaced. After reviewing the unfavorable maintenance history of the deck, I was still confident that we could save it. But you never know until you get into something like this: it is exploratory surgery.

How Do You Clean Such a Rough Deck?

First, it is important to understand the tools and products required to do this type of wood restoration. Then, the process is key – strict adherence to the process. Here are the steps we took…

1. Low Pressure Wash with Proper Chemical Mix: this is the poster child deck of why low pressure washing is important. High water pressure would really damage a deck at this stage of its life. Same with chemical knowledge. You have to be somewhat aggressive in the chem mix to clean a deck like this, but if the mix is too “hot”, that would also damage the wood. Notice the emphasis on not damaging the wood, that is a key to wood deck maintenance. This is exactly why we rarely publish the chemical mixes that we use.

Internet readers tend to skim. Grab a hot mix out of an article and apply it wrong in the wrong situation and we have a big problem. I will say that generally, chemical application during pressure washing is a misunderstood method. With the ease of downstreaming chems through a pressure washer, the temptation is great to take the easy way. We prefer what is called the “dwell” method, where the chemical is not applied by the machine. It is applied through a simple garden style pump sprayer, and allowed to sit for as long as it will stay wet. Rinsing just as the chem wants to kick off and dry makes for the easiest wash. There were actually two chem applications applied successively here. One was the cleaner, and the other was the brightener (to neutralize the ph of the wood).

Rinse thoroughly. Then, rinse again.

After washing, always allow at least a couple of days of good drying weather before proceeding.

2. Soft scuff at 80 grit on a pole sander. That’s right, pole sanders aren’t just for walls. They work great on decks. It is rare after a proper and aggressive chemical wash to have to power sand. It is usually one or the other. But it is always a good idea to do a “scuff” sand after pressure washing, because the washing process does raise the grain a bit and leave some “hairs”. A quick float (and then vacuum), and you are ready for oil application.

3. This deck has weathered pretty hard in a tough exposure for 14 years, so it would be an understatement to say that the wood is very “open” to receiving oil. We refer to this condition as “thirsty”. We applied a high quality transoxide pigmented penetrating oil on this deck, and let the oil sit for a good 15-20 minutes before rag wiping the excess. This translated to about 8 courses at a time, taking care to get oil into the grooves and end grains as much as possible. We also replaced several courses of the deck that were either rotten or about to rot.

Why Isn’t He Specifically Naming Products?

I thought you might be thinking this.

The answer is because if you are reading this, then you are a member. And if you are a member, then you can ask and I will answer. More importantly, if you are a member with a deck in need of restoration, I am probably already prescribing for you the products and process that you need specific to your own deck situation based on photos and history you have provided.

The formula that we used on this case study might be too stiff for your situation. Chances are, it would be. As above, it is our responsibility and the charter of ipehelp.com to set members up with the right combination of product and process for their exact situation. It is education, and we keep it as painless as possible.

I mostly shared this story with our members so that you can see why it is critically important to maintain your deck investment.

And there will be lots of stories here about that!

Tags: rot