Spring is here and it’s time for exterior house-painting in the San Francisco Bay Area, so I thought I’d share some thoughts on exterior painting process and techniques. Below is a sample sequence from prep to finish.

Start by CLEANING, which Entails manual scrubbing or 1500-2000 psi removal of dirt and other organic material from the building. If necessary, bleach is used to kill mildew, and we’d use a bucket and stiff bristle brush to remove any organic material left by the power washing process. Care must be taken not to use the power-washer near windows and doors so as to avoid getting water into the house. Window frames can be washed by hand. Allow to dry.

SCRAPING: Removal of the loose and peeling paint is probably the most important step in ensuring a long-lasting paint job. Paint that is imminently failing but not peeling may be removed using heat guns or chemicals. We prefer heat-gunning as chemical stripping can be messy and the results hard to control. We use high quality scraping tools, such as “Pro-Prep” or “Sandvik” carbide. Areas of degraded paint that are in risk of imminently failing, but are not readily scraped, should be removed using heat guns. The prepped areas are then be rough-sanded to knock down the edges and prepare the surface for priming.

A word about LEAD: Before scraping or sanding lead-based paint one should take the proper steps to protect self, others and the environment. I won’t get into lead ordinances here. We follow proper lead abatement procedure, and use 4-6 mil. plastic, hepa-vacuums and particulate respirators.

* NOTE– In cases where you want to prep less, or wish to avoid creating a lead-abatement issue, you can improve your shot at durability by apply an (eco-friendly!) clear binding primer like XIM “Peel Bond” or Global Encasement’s “Prep LESS primer”.

A word about WINDOW GLAZING: Glazing takes over a week to cure before painting, so try to get your failed glazing removed, primed and re-placed as soon as possible.

SANDING: Sand the scraped areas/paint edges to remove loose matter and minimize the profile to help prevent further peeling. Sanding can also be used to de-gloss shiny paint. However, if the pre-existing paint is highly glossy, then it is best to use a primer with high adhesion.

FILLING HOLES: Bottom line with filling is don’t use exterior spackle; it absorbs moisture and bubbles later on. Use epoxy fillers like bondo or better yet, the slower-drying but FAR superior “Restore-It”. You can find a ton of great fillers at West Marine or Tap Plastics! But first make sure the substrate is sound. If there is dry-rot present, or the wood is not solid, use a liquid wood hardener (We’ve used Zinsser clear binding primer as an eco-friendly alternative to the noxious “Restore-It” hardener.

CAULKING: We use urethane-reinforced caulking (55 year) to caulk all vertical seams and window/door openings. In challenging situations (Front Steps) we may use a poly-urethane caulk like “sika-flex”

REPAIRING STUCCO: Make sure the substrate is clean and sound, (wash/prime first) then fill/bridge small cracks with flexible caulking or elastomeric patching compound as required. For larger repairs use a ready-mixed stucco patch, or a cement-based, rapid-setting stucco patch.

PRIMING: Try to pick an appropriate primer for the job. We like the acrylic multi-purpose primers that stick well, block stains and handle galvanized metal or recently cured concrete. Dunn Edwards “Ultra-Grip” and ICI “Gripper” come to mind.

As a San Francisco Painting Contractor, we see a fair amount of dry-rot repair, redwood trim replacement and deck re-finishing on the exterior painting jobs.

As for Dry-rot: In cases where the trim can be repaired, make sure remove the really rotted wood, then soak the affected area with multiple coats of a dry-rot hardener such as “restore-it”.  Use a two-part marine epoxy as the filler. Often, It’s best to replace rotted wood completely. In San Francisco, old trim can be custom milled for an exact replica at Lowpensky Molding, if you provide them with a sample.

When re-finishing decks, several pointers apply: First, use a brightener to remove greying and stains. Next, power-wash the deck thoroughly (keep the tip fairly close to the surface, and use even strokes). Use a second round of brightener and more washing if needed. Finally, after a light sand and vacuuming, a clear decking stain (Cabots timber oil, penofin, superdeck) should penetrate the wood, but not sit on the surface. Avoid applying the stain in excess or in direct sunlight, and wipe off excess stain (excess stain will gell over, and create an un-even and unmanageable finish down-the-road. Be sure to dispose of stain-soaked rags in a container of water to avoid spontaneous combustion Soaked rags left in a hot or sunny location will spontaneously burst into flame. I’ve seen it happen!………..