Refinishing a Pressure Treated Deck

How to stain and repair a peeling pressure treated wood deck.

We've lived here for 5 years now, and have always talked about fixing up the deck and we finally got to it (one afternoon, and two Saturdays). After researching on the web for ways to remove deck stain, and paint, I was a bit perplexed because I wasn't sure exactly what was on our old deck, which makes a difference as to how you should proceed, for both removal and applying new deck stain or new deck paint. (Sorry I seem to have messed up the layout of this article.)


This close up of our pressure treated pine wood deck, shows cracks, peeling and some wood rot. My first idea was to replace the boards. Cost would have been around $350 or so. That plan was vetoed by the budget committee. My second plan was to flip the boards over, as the under sides looked much better and the boards are 2 x 6s and only the top surfaces had issues. The deck was still very sturdy structurally, minus 2 rotting boards. In the end, the budget committee/planning board told me I had to "work quickly" with what was there. So the decision was made to fix what was there, without turning this into a lengthy project. Note: click on photos to enlarge them.


Here's a quick after shot, for a before and after comparison.


Here's a before shot of the deck.


This is a before shot looking down one side of the deck.


This is a before shot of the other side.


You can see that it was in need of TLC.

Nowadays decks are all stained, and the stain can be opaque, giving the appearance of paint. I recommend that you take a piece of your deck (a stair riser board perhaps, as I did, or a chip of your current finish) down to your local paint shop. They'll give it the look, feel, and scratch test, and might even throw a few chemicals at it to see how it reacts to identify what's currently there to determine your best next steps.

Here's a railing section where the pressure treated wood has "cupping" and popped up deck screws. Exposed to years of wetting and drying the boards swell and then shrink, pushing up screws and nails.


Here's a similar example at the corner of the railings. The cracks in the posts are typical of how pressure treated wood dries and ages. Although it doesn't look so nice, it doesn't affect the structural integrity of the deck. If you are thinking of using wood putty to fill the cracks don't. At least that what I read on the web. It seems that when the wood expands and contracts with the outside temperature, the putty will come out, or something else not so good.


Not knowing if I had paint on here or stain, I took a guess and tried stain stripper (this was before I eventually took a sample to the local paint shop). The directions have you mop it on thick and let it sit, while making sure it doesn't dry out. "Lifting" of the stain is supposed to begin after 5 to 45 minutes. I let it go for about 35 minutes, misting it every so often with the a hose. You'll need a paint tray, a stiff brush, rubber gloves, and goggles to do the job.


This a shot of the deck with the stain stripper on it. Great time to take a breather as it does it's thing.


Here's a close up of the stain remover in action. Well nothing much happened to the stain, even while working it with a stiff brush, but the deck did get a good cleaning up of mildew and algae. With not much in way of results, I began to wonder if I had paint on there instead of stain. Perhaps some bits came up, but not much for sure.


I then gave the deck a good rinse with the garden hose to remove the stripper, and started in with a 2,600 max psi pressure washer. This yielded much better results than the stripper. Anything loose (and then some) came up. I couldn't have easily removed all of the stain/paint, so I only removed what wanted to come up and then a bit more. A pressure washer can damage the wood if used too close or if you use too much pressure on soft woods like this pressure treated pine, but I didn't care much, as the surface of the boards couldn't be much worse. Above shows the results after stripping, pressure washing and drying.

A Note About Pressure Washers in The Wrong Hands
Many professional pressure washing services state on their websites that much damage can be done by pressure washing at too high a pressure. They state that they use powerful cleaners and strippers that can only be purchased through dealers that work directly with them. They state that the chemicals that home owners can purchase, at home centers, can't do the job well, and thus home owners resort to using too much pressure, which can potentially cause serious damage to their wood. Because the professionals use these powerful cleaners, they state that they only use very low pressure (in the hundreds of psi, versus thousands as I have used). I believe the above statements to be true, so if you are not comfortable with taking the risk of ruining your deck, have a professional do the work. I on the other hand only need this deck to get through a few more years as we have plans to remodel it in the future. Also, I'm a die-hard do-it-yourselfer, and I make mistakes sometimes and learn from them. I'm willing to take chances and sometimes I pay the price. So you have been warned, and professionals will be happy that I've added this disclaimer. Onwards...

You can rent a decent pressure washer at your home store, but I decided to buy a $300 model and then after using it for a few weeks, for pressure washing everything on my property, I'm planning on selling it on Craigslist. Much cheaper than renting for a few days, if I get a decent price for it. If not, hey I'm already falling in love with it... and might just have to keep it!


By the way, the pressure washing will create a mess of flying debris about 10 feet out from your deck, so you might want to throw down some drop cloths, or plastic to protect your patio or whatever. Keep in mind if you put plastic over your plants you could bake them in hot sun.


After stripping, pressure washing and drying (4 days of sunny warm weather drying), we went to town banging down every nail on the deck. Some had popped up quite a bit due to the shrinking and swelling of the wood in our variable Northern climate, and others just needed one good whack to seat them below the surface in preparation for our next step... sanding.


The great thing about doing these projects yourself is that sometimes you can justify a new tool purchase! I had a 5 inch orbital sander, but it wasn't up to this larger job. What I wanted to buy was a Makita 7" orbital sander, that the professional painters rave about online, but it has been discontinued and I couldn't find it quickly, so the best I could do was a 6" Rigid orbital sander with higher amps than the smaller sanders. This did the job perfectly. I ideally wanted 40 grit paper, but the local home store only had 60 grit (finer than 40). 40 would have done the job quicker, but the 60 was fine too. We didn't use anything finer after the 60 grit, and it all looked great. Some might want to do a resand with 100 or so.

We sanded to remove more of the stain/paint, but also to sand down some of the cupped boards and to smooth down the rough board surfaces (cracks from over time, and roughness caused by high power pressure washing removing softer grains of the wood). I also used my smaller 5" orbital sander to round the railings around the deck and on the stair rails. This really helped make the wood look in much better shape.


The railings shown earlier, that were lifting off the posts... I fastened them down with stainless steel screws. These did a nice job of sucking the railings back in place. Stainless wood screws are great for decks and pressure treated wood, but they are expensive, and even the square head type I used are easy to strip if you drive them too quickly or if you don't apply enough steady downward pressure on your screw gun. After that I used my smaller 5" orbital sander to make smoother transitions from one deck railing to another.


Here's another example of using the sander to correct warped, misaligned boards. I also rounded any other sharp deck edges where hands, feet and other body parts might prefer a softer contact.


Not too exciting, but here's what the boards looked like after stripping, power washing, sanding and then finally blowing the whole deck clean with a leaf blower. This removes all loose debris, and also some stain/paint flaps that were still holding on by a thread.


As mentioned before, I didn't know exactly what we had on the deck already (stain or paint), so I took a stair riser board off the deck steps, down to the local paint shop experts. Even they (2 workers and a few professional painters) had a hard time identifying what was on my boards. In the end it was determined that it was stain, but that it must have been applied when the pressure treated wood was still wet, as the stain was peeling off. Anyway, they recommend Sikkens opaque stain for our job.

Sure enough, this stuff was great. I took what they gave me without research other brands, and I think it was a great choice. The first coat is recommended a primer and then Sikkens recommends a second coat. Well we have kids, pets, jobs, so we are one coat, one afternoon stainers. So one coat it was, and wow, what great coverage, and it did a great job of filling and smoothing much of the smaller surface cracks in the deck boards. I mopped it on fairly thickly in order to get it down into the cracks, and then smoothed out the surface.

The color department (shown wearing overalls above) wisely decided to go with a color similar to what we had previously in order to get away with one coat, and if we missed a spot, nobody would be the wiser. I never really liked the gray, but hey, you have to pick your battles, so gray it was, again...


Here's a close up of the Sikkens stain on the deck in their "satin" finish. Once I saw the outcome I was so glad that "the planning committee" made me stick with the existing boards. The deck is smooth, splitter free, and looks great! Time will tell how it holds up under heavy traffic, and our harsh weather. I'll have to update this later this summer, after use. Click on this or any photo for a closer view.


Even the railings looked and felt great to the touch with the rounding I did with the sander and with the new thick stain on.


Here's what was a misfitting railing joint, now looking much better.


As mentioned earlier I had 2 rotten boards. This was one of them. Ideally I would have replaced them before the other work, but long story short, I did them after. First I tried using a hammer from underneath to pop them up (that's why you see wood debris kicked out of the rotten section. That didn't work so well, as the boards were tucked under the siding at the house, and under the railings on the other end. Out comes the saw! I love to have the right tool at the right time.


I cut the board in the middle and pried it up. You can see the 2 halves on the railing above. The photo that is 5 photos up, has the new board in place (look for the nicer piece right in the middle). I used stainless steel screws to put it in place after sanding and staining it in the workshop. I was lucky and had a few pieces of 2 x 6 pressure treated pine that had been drying out for about 2 years. So they were ready for stain and installation right away.


And here now is the finished result. We are all happy with it, including our young kids who will no longer be getting splinters, and it's no longer the deck we have to be embarassed about when guests are over. It's done and ready for summertime.

I guess one main point of this article is that if you think your deck boards are shot, they might not be. If they are structurally sounds (no rot, stable and secure) then they may just need a facelift.

From a few feet out, you might even think we have Trex! But when you get closer you know it's the real thing, not some cheesy plastic imitation. There is nothing like real wood to me, even if it does requires TLC from time to time.


Both cat and dog agree the new deck is better!

Resources
To come soon.

Products, Materials and Tools I Used (in progress)
Drop Cloth
Water Hose
BEHR Premium Stain & Finish Stripper No. 64
For stripping: Googles, Rubber gloves, Stiff brush with handle, Paint tray
Husky 2600 PSI, Gas Pressure Washer
Hammer
Grip Rite Stainless Steel Wood Screws
DeWalt 1/2 In. Compact 18 V Compact Drill
RIDGID 6 In.VS Dual Orbit-random Sander
DeWalt 5 In. Heavy Duty Random Orbit Sander
60 grit sandpaper for sanders
Leaf blower - Toro Electric Ultra Blower
Sikkens Rubbol Solid DEK
Brushes, Paint trays
Beer, and inspirational music


My Standard Disclaimer: This is what I did. This does not mean this is the best way, the right way, to building code, or even safe for your needs. So you are on your own with your project. I make no promises about the information presented here. I'm just a do-it-yourselfer, not a professional at all, sharing my story. So if something goes wrong with your project, you are on your own. Good luck, and have fun!

All content and photos, copyright 2009, Dover Projects
_____________________________________________________________
My Other Articles

• Fix Double Hung Window Sash Cords
• How to Caulk a Bathtub
• Refinishing Pressure Treated Deck
• How to Build a Sandbox with Seats
• French Drain Design
• How to Build a Flagstone Patio
• How to Build Porch Railings
• How to repair a sliding screen door
• Replacing Broken Window Glass
• Barn Foundation Repair
• Knob and Tube Wiring - Replacing
• Recessed Kitchen Lighting & Design
• How to Drywall a Ceiling
• How Roofers Can Win More Jobs
• How to Insulate Basement Rim Joists
• How to Insulate an Attic Door
• Radiator Heat Reflectors
• Air Sealed Dryer Vent
• Toilet Tank Water Savers
• How to Check for a Leaky Toilet
• How to Clean Refrigerator Coils
• How to Make a Pet Door
• Energy Efficient Pet Door