Mondo Condo Failure

An ounce of following the product data sheet can save a ton

By Clayton Des Roches, Paint Quality Assurance Inspector


This inspector was recently asked to write a repaint spec for a project that involved a premature (and fairly thorough) coating failure on a very posh condo complex situated in a high-price area of town.

This five-story wood-siding building was recently finished with a water-based semi-transparent stain. Within two years of construction, bare wood was already showing on the southern elevation, and as of the inspector’s visit, the paint job was virtually gone; judging by the condition of the bare wood, it had been gone for years. The exposed wood was so dry it was splitting and noticeably bleached.

The other sides weren't quite as bad, but still exhibited substantial areas of failure that no owner should expect to see so soon.

The inspector gritted his teeth and prepared a repaint spec. Re-coating with a semi-transparent stain was not an option. Semi-transparent stains are feasible only when the wood and/or existing finish are in good condition; once the original coat has failed and the wood is bleached out, applying a semi-transparent stain yields a patchy, unattractive appearance. So the inspector specified repainting with a solid color stain.


All told, the inspector’s repaint spec for the southern exposure walls called for these steps:

  1. Mildew treat and powerwash to remove all surface contaminants
  2. Scrape off whatever bit of stain is remaining
  3. Power sand off the dead layer of wood on top
  4. Apply a complete prime coat of a product approved under MPI #5 Primer, Alkyd/Oil for Exterior Wood (and if a waterbased product had been required, MPI #6 Primer, Latex, for Exterior Wood)
  5. Apply two coats of solid color stain (MPI # 16 Stain, Exterior, Water Based, Solid Hide)

Repainting the non-southern exposures

There was a little bit of stain left on the other sides, so that part of the spec called for mildew treatment, powerwashing, scraping and spot priming in areas where the deterioration was the worst, and all surfaces finished with two coats of the same solid color stain. Fortunately, power tool cleaning would not be required on these sides.

One might think that not applying a full prime coat on all sides would create an aesthetic problem, but fortunately, the building’s configuration is split up such that any slight difference in appearance between the southern exposure and the other walls won't be an issue.

Also, most products approved under MPI 16 Solid Latex Stain are self-priming when darker colors are used; if light colors are specified, a primer is required. The repaint product for this project was a dark “self-priming” solid color stain, so this inspector determined a full prime coat on the less-deteriorated walls would not be required.

The price tag for this repaint project? $165,000; not only a tall figure, but certainly one the owner had not budgeted or planned for.

This begs the question: why did the original paint job on this very expensive piece of real estate fail so quickly in the first place?

What went wrong

#1: Do you really want a semi-transparent stain for this project?
The owner and architect’s vision for this building was to have a natural appearance, so they specified a semi-transparent stain that enabled the wood grain and texture to show through. Our job as paint inspectors isn’t to insert ourselves into the creative process; however, there are facts a specifier should know if they choose a semi-transparent stain. With this chemistry, there’s no film build, so very little protection is provided to the wood surface. Here’s what the MPI Painting Manual has to say about semi-transparent stains for wood:
“Semi-transparent stains…have a low level of pigmentation that allows the wood grain and texture to show through, giving a natural appearance. Unfortunately these coatings do not significantly protect the wood from degradation by UV or water, and must be recoated more often than surfaces coated with complete hiding paints or stains. Not for pre-primed or badly stained and discolored surfaces. Will not prevent the natural weathering of wood substrates due to semi-transparent nature and very low film build. Use two coats…”

In exposures like the Pacific Northwest where you get rain rain rain along with hot summers, degradation can occur in as little as six months to a year. So in general, let the specifier be warned: a semi-transparent stain offers no kind of exterior long-term protection in this kind (indeed, most kinds) of exposure environment.

Note that if the coated surface is not directly exposed to UV or extensive weathering, semi-transparent stains may be used with no problem.

So by choosing a semi-transparent stain, this project was condemned to more frequent repaints. But should bare wood have been showing less than two years after application? A little detective work yields the answer...

#2: Did the contractor follow the spec? Better yet: did the spec follow the product data sheet?
One might assume that on high price real estate, extra care would be taken to assure the finish is applied properly and according to spec. The inspector surmises this was not the case on this job: judging from the bare nail heads in the siding, only one coat of stain was applied (badly at best) on the ground at the jobsite; it was then installed, and the painter walked away.

As a rule in this inspector’s experience, no conventional coating goes on in just one coat at new construction. And semi-transparent stains require a minimum of two coats per the reference in the MPI Manual above. Applying one coat fails to meet the standard of good practice.

So if the industry-standard two coats had been applied, the owner and specifier could have reasonably expected longer life than they received. However, upon further investigation, this particular product’s technical data sheet states that three coats — two coats of the tinted stain product followed by one coat of a clear — are required in order to get the level of protection advertised with this product.

Why You Read the Product Data Sheet

If the contractor had applied the product according to the stain manufacturer’s instructions, the owner certainly should have had a few more years of service prior to the first repaint; furthermore, the repaint would likely have been easier. Applying the required three coats is cost-effective at original construction because the scaffolding required for access is already in place and the cost is absorbed into the overall construction cost. On the other hand, setting up complete scaffolding for a repaint project means the repaint bid bears the full weight of the cost — and unfortunately, the building’s configuration requires the use of complete scaffolding instead of just lifts for repainting, which increases the cost considerably.

Also, note that the failure to apply three coats may not entirely be the contractor’s fault. Blame could also lay with the specifier: a good painting spec would have taken note of the requirements specific to this product and clearly spelled out the need for three coats. The inspector hasn’t seen the original spec, so it remains a mystery whether or not the specifier included this important piece of text.

Finally, the value of using inspection cannot be overlooked or over-stated. If during construction the owner and architect had specified that a third-party inspector be present to verify that the required product was being applied properly and according to spec, it is fair to assume that all three coats would have been applied before the contractor left the site. For a project like this, inspection would have cost $2500. That seems like a small price to pay up front in order to avoid a $165,000 repaint job just five years after construction.

#3: Specifier didn’t require an MPI-approved product
We’ve established that in general, semi-transparent stains are not ideal choices for long-term protection. And this was a LEED project, so the architect and owner were anxious to get a low VOC (water-based) product. We understand that…but the particular water-based product the specifier chose was not MPI approved. Water-based stains are relatively new technology that lack the decades of performance data that solvent-based products offer, and there can be a wide range in durability between different water-based stain products from different manufacturers.

So if the architect wanted confidence that he was getting a durable product, he could have specified that the chosen product be approved under MPI #156 Stain, Exterior, Water-Based, Semi-Transparent . Products approved under MPI #156 have been tested for characteristics including appearance, applicability, resistance to mold/biological growth, and have undergone 500 hours of accelerated weathering testing with no blistering, chalking, checking, cracking, flaking or loss of adhesion, as well as minimal color change.

While we don’t know how 500 hours of accelerated weathering correlates to real time, we do believe that third-party data verifying that a product meets this requirement gives the specifier some peace of mind and reasonable expectation that the product will provide at least “good” performance consistent with what may be expected from this class of product.

The Economics of Failure
So whose fault was it? Candidates include the architect, GC, developer, painting contractor, and whoever did the final quality control on the work. Reviewing the price tag for negligence, we find:

  • Original painting contract: approx. $50,000
  • Cost to repair after five years (and failure started after two years): $165,000
  • Cost (might we say “investment”?) for specifying inspection at initial construction that would have delayed, perhaps substantially, the need for repainting AND very likely would have reduced the cost of the repaint: $2500

And these are just the hard costs. The condo residents are paying as well. The original condo owners paid a premium price for their units and just two years later, their building in a prime neighborhood had a shoddy finish that suggested the building was very poorly maintained. How did that affect their ability to re-sell their unit? And how did it affect the building owner’s reputation? We surmise it hurt. And a few extra dollars invested in the beginning could have saved the pain









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