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Steps To A Proper Deck Restoration & Refinishing.

By Guest Post

Mike’s Advice / Exterior Renovation & Landscape Construction

Tuesday, September 25th, 2018 @ 2:48pm
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Article By: Terry Owen, The Wood Surgeon,

#1 Inspection… is it a keeper?

Where wood meets wood (butted boards) or wood meets concrete are the most common places for hidden rot. If you haven’t protected your deck in a long time or not at all, take something hard and pointy like a flathead screwdriver and poke around. You will probably find soft or even hollow boards that require replacement. Counter sink nails and tighten screws on the salvageable floorboards. Poke the joists as well to see if they are rotten. Your joists should be pressure treated wood, at least 2×8 in size and no more than 16” apart with hangers attached to the ledger board if your deck is attached to the house.

Look under the deck to see if the posts are cracked and/or crooked. Are there concrete piers under the posts and if so, have they heaved? There is no sense in refinishing the surface if the substructure is rotten and/or unsafe. By code you must have a 36”high rail system if your deck is higher than 24” off the ground. Check it for movement and rot. Your rail should have 4×4 (at least) posts every 4-5ft secured to the deck with bolts. Your balusters must be vertical, secured by 2-2×4 rails and spaced no more than 4” apart. See building codes in your area.

#2 It’s a wash

A power washer is a removal tool and not a finishing tool. It can also be a weapon in the wrong hands. A 2500/3000 PSI with 2.2/2.5 GPM (gallons per minute) pressure washer is plenty to do the job. Use a wide fan and determine how close the wand should be to the surface by experimenting on an area that is relatively unnoticeable. If you see the fibres of the wood starting to rise (bur) back off slightly.

If your deck has a significant amount of old product on it you may want to apply a Stain/paint remover. Just be sure to follow the instructions on the container, wear proper protective gear and protect your cherished gardens. If the old product is raised and chipping the washer will remove most of it without harsh chemicals. An anti-mildew treatment is key in this process and highly recommended. I still like TSP for its effectiveness and they have improved the formula to be biodegradable. Again, test your concentration level and wand distance on an inconspicuous section of your structure. You want it to be as strong as possible without burning.

At this point you will feel inspired when you start to see wood grain and want to move ahead to stain but don’t be hasty. If you are really successful at this first stage, you will have removed approximately 80% of the surface mildew, leaving (approx.) 20% behind and also allowing the residual fungus deep in the pores of the wood to rise and settle on top of the boards. Leaving this mildew and staining over will allow it to continue to grow under your protective coating and eventually rear its ugly head when it pops through in the form of peeling.  

The inconsistencies in the porosity of the surface created by the spray will cause flaws in the coverage of your protective coating. Large wide open pores or cells will take in a lot of stain. Small or closed pores will not take stain. Let your deck dry for a couple days before starting the 3rd step.

#3 Sanding… an art form

For this stage you will require sunshine, a belt sander, palm sander and a sanding sponge along with belts and paper. This is the least glamorous part of the project to say the least, it’s dusty, dirty, and tough on the muscles and potentially a health hazard if inhaled. An N95 rated (or higher) respiratory mask tight fitting work gloves and goggles are required.

Many people use the upright floor sanders that you can rent at your local home improvement store. I can’t blame them for this because there’s usually a lot of deck to do in a short amount of time. The problem I have with these machines is that they are made for indoor hardwood floors, they are heavy, 8” wide and perfectly flat. Your deck boards are not generally 8” wide nor perfectly flat. If put in correctly (crown up) your floor boards should be slightly convex if not, over time they may become slightly concave (cupped). Neither surface can be sanded with that large machine without taking too much wood off some boards and/or not enough on others.

This is why my crew (the dedicated pros that they are) are down on their hands and knees with hand held 4” belt sanders that are easier to manipulate. We start with a heavy 50 grit belt and work backward on the boards to remove the remaining mildew and old product. The palm sander helps to finish the board ends and other areas that can’t be reached by the belt sanders.

We also do what we respectfully call an Amish style sanding using a sanding sponge wrapped in sand paper and by hand, sand the areas that the palm won’t reach; we then do a finishing and detail sanding by taking a lighter 60/80 grit and repeating the process. Finish sanding is meant to create consistency in the porosity of the wood so that stain coverage will be consistent and absorb as much as possible. Remember large open pores take a lot of stain and crushed pores take no stain.

Detail sanding means that every nook and cranny has been addressed so that we will have a well-protected work of art when completed. Many think that staining is the only artistic part of the project but proper preparation of your canvas is an art form within its self. If you leave your belt or paper on too long it will crush the cells and not allow stain. If you use the wrong grit on a bare surface it can leave marks or scars that won’t show up until you stain. If the finish is inconsistent your translucent stain will go on blotchy. If it rains during your project and you can’t protect the surface, your finish sanding is a do over because the moisture has furled your surface. Direct sunlight will cause discoloration so the part you sand today will be a different shade than what you sanded yesterday. This will be a big deal if you want a natural wood grain finish.


Staining Maintenance vs Aesthetics

After all that hard work and now that you have a better than brand new deck or other structure, it is time to decide on how to protect it.

Stain Options:

Clear coat
– let’s get rid of this one right away and forget we ever heard the term! They should never have been created for outdoor use. They provide no protection from sunlight and dissipate almost as fast as they go on.

Translucent – the only way to have a protected natural wood grain finish. It is meant to accentuate your canvas in the form of your newly restored wooden structure. There are colour choices such as light or dark or reddish for example. The lighter “natural” stains will allow that wonderful colour spectrum of wood grain in cedar to be the star. It’s a one coat application that has to be a gentle balance between too little and too much.

Semi-transparent – will provide more consistency in colour and the depiction of wood grain. This is an alternative for those who want a wood feel without the eccentricities of the different colours coming through. After additional maintenance coats it loses its transparency.

Semi-solid – has a little more pigmentation than semi-transparent.

Solid – Just like it sounds; solid colour like a paint and can be colour matched to other structures. Perfect for horizontal surfaces, very clean and can provide great accent and contrast when combined with natural finishes. Apply 2 coats within 24 hours.

All stains should be applied with a proper stain brush. With a brush you can work the stain in to the surface of the wood and control the consistency. Sprayers don’t give you that luxury and can get very messy with floating stain landing on windows, pools and even automobiles. Rollers will keep you off your knees but can create pooling that will peel. 
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