You should clean with TSP before chipping/sanding. TSP will clean the dirt and grease off the surface of the item before you grind the dirt and grease into the pores by chipping and sanding. But cleaning afterwards is better than not cleaning at all.
By de-glossing the surface first using TSP, it will dull the surface and allow the new paint to stick. Normally the areas are sanded and otherwise prepared before they are washed with TSP. Be sure to rinse with a clean, damp sponge and allow the surface to dry thoroughly.
To clean walls with TSP, mix the powder into a bucket of warm water until it's completely dissolved (be sure to wear rubber gloves and goggles for protection). Dip a sponge into the TSP solution and use it to wipe down walls. Rinse the surface with clean water and let dry before painting.
In all seriousness you should power wash first and then sand it. Sanding will make the stain last longer or you'll be power washing and staining every one/two years. Sanding and replacing any rotting boards will buy you at least another 6/7 years if you do it correctly.
You can paint as soon as the surface is dry. It is okay if paint cannot be applied immediately, but try to paint within a week, before dust or other debris can build up.
TSP is still sold and used as a cleaning agent, but since the late 1960s, its use has diminished in the United States and many other parts of the world because, like many phosphate-based cleaners, it is known to cause extensive eutrophication of lakes and rivers once it enters a water system.
Rinse Surface
As the TSP solution dries, it can leave a white powdery residue on the surface that has been cleaned, which needs to be rinsed away.
The post-pressure washing phase is crucial in the deck maintenance process. It sets the stage for sanding, sealing, or staining, ensuring that your efforts in cleaning and preparing the deck lead to a beautiful and long-lasting finish.
Why does my wood appear fuzzy after pressure washing it? Pressure washing removes the outer layer of dead wood, and can sometimes make it look like it has short fuzzy hairs. This is caused by the tearing of the wood fibers.
The high-pressure water stream dislodges dirt, grime, or paint from surfaces and then washes it away into a drain or onto the ground.
A critical step in a professional paint job is thoroughly cleaning the surface. TSP removes oils, paint flakes, and residues, ensuring better adhesion for fresh paint.
For general cleaning, mix 1/2 cup laundry detergent or trisodium phosphate (TSP) in 1 gallon water. Scrub with a stiff brush and rinse thoroughly with water. To remove mold, mildew, algae, and lichen, mix 1 quart household bleach and 2 ounces TSP detergent, or a phosphate-free substitute, with 3 quarts water.
Cleaning Up and Removing Smoke Odor
Smoke odor and soot can sometimes be washed from clothing that can be bleached. Measure 4 to 6 tbsp. Tri-Sodium Phosphate and 1 cup household cleaner or chlorine bleach for every gallon of warm water you will use.
Dawn: You can use the original blue Dawn dish detergent instead of TSP to cut through surface grease. Pressure-washing: This is another alternative to cleaning outside surfaces without TSP. With sufficient and well-calibrated water pressure, it is possible to clean tough areas with only the pressure of the water.
Sand Your Workpiece
Always start with a coarse grit belt or disc and work your way progressively through finer and finer grits until you reach the desired level of smoothness. Don't press down too hard or you'll clog up the abrasive disc or belt; let the weight of the tool provide the right amount of pressure.
It is only when pressure-washers are used improperly that they damage wood decks. Proper pressure-washing does not harm wood decks and effectively cleans the wood; removing unwanted buildup and helping to restore the look of the deck. Myth 2: Pressure-washing is a simple task that I can easily DIY.
When the deck is dry (36-48 hours after washing, depending upon humidity and weather conditions), it's time to sand the surface. You can use a pole sander with 80-grit sandpaper to remove all the loose wood fibers that were lifted by the pressure washing.
Deflection refers to how bouncy a deck feels when walked on. Excessive spans and undersized joists and beams are the primary causes of bounciness. Racking, or more commonly called swaying, refers to when a deck moves from side to side.
The deck must be completely dry before you start sanding. As previously mentioned, this usually takes at least 24-48 hours, but can vary based on weather conditions and wood type. The wood should return to its natural colour and feel dry to the touch.
Pre-treatment of your wood deck, or patio, is important, as this will help to soften up thick dirt or grime before high-pressure washing. For heavily soiled decking, apply a wood-specific, Composite cleaner or detergent and allow to soak in for 5-10 minutes.
Use long, overlapping strokes and maintain consistent pressure to ensure even coverage and minimize the need for additional passes. Regularly change the sandpaper to maintain optimal abrasive performance. Use a sanding sequence that progresses from coarse to fine grits to achieve the best results.
Exposure to TSP can cause serious eye injury and skin irritation, even in diluted form. TSP can also be harmful if swallowed or inhaled. We recommend wearing long pants and sleeves, waterproof gloves, goggles, and a respirator when preparing and using TSP.
Simple Green Surface Prep cleans and degreases surfaces prior to painting to remove the dirt, grease and unseen oils that cause paint to be uneven, crack or peel. The phosphate-free formula is a safer alternative to TSP.
Borax is a considered a more natural alternative to TSP. Sodium borate (as its called by chemists) is also alkaline and also consists of white colorless crystals that dissolve in water.