Liquid stucco good choice for brightening up house

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This article was published 21/08/2005 (7439 days ago), so information in it may no longer be current.

QUESTION — We live in an 80-year-old two-storey house in River Heights and are in the process of gathering quotes on repainting our stucco. What are your thoughts on flexible stucco? It appears to be an excellent product that, we are told, will eliminate the cracking and last a lot longer than paint. Is this a better way to go than simply painting the stucco? Are there concerns we should be aware of? Will covering the outside of the house in this material cause problems with breatheability, etc.?

We look forward to your thoughts and response.

–Barry Jansen, e-mailANSWER — This is a question that I often get at least once or more per year. I will explain what the material is that you are referring to as “flexible stucco” and give my advice on its use.The material often referred to as “liquid stucco” or “flexible stucco” is simply a very high quality finish known as elastomeric paint. It is a paintable or sprayable liquid coating that has a high vinyl content and resists wear well. It can be applied over stucco in a thickness that is considerably more than traditional acrylic paint.

This gives the coating excellent flexibility while ensuring high durability and long-lasting finish. One benefit of the heavy thickness is that it will bridge normal hairline cracks and prevent them from opening up over time, unlike traditional paints.

The reason that this finish is so unique, as opposed to traditional paints, is that it is highly breathable, even in the heaviest of coatings. This allows the siding, stucco in your case, to release moisture that may enter the wall cavity. Multiple coats of regular paint may actually trap moisture behind, rather than allowing its release. This ability is a critical function of any exterior siding in our climate. If moisture cannot escape the wall cavity, the stucco and wall sheathing will become moisture-damaged or the paint will bubble and peel very easily.

You are correct that this is an excellent product, but it does come at an extra cost. Because of the thickness of application, the coverage is much less per volume than traditional paint. However, this added cost should be weighed against the durability and savings over time. This material is highly resistant to deterioration from ultraviolet light and water and may last two to three times longer than normal finishes. The convenience of not having to repaint every few years may be worth the extra expenditure.

You may have seen some information about this or similar products promoted as being “Liquid Insulation” or adding significant R-value to the exterior wall. For the most part, this is creative or false advertising, although adding an elastomeric finish may improve the performance of the “building envelope” in your home. The building envelope is the entire exterior of the home including walls, windows, doors, attic and foundation exposed to the exterior.

This system in the home works best if minimal air passes through from the outside to the inside, or vice-versa. While still allowing moisture to escape the exterior walls, this heavy finish may prevent air movement through the wall system. While not adding any true insulation or R-value, this may improve the heat retention of the home, slightly. It may prevent “wind-washing” of the exterior wall cavity, improving the overall performance of the building envelope. This provides a similar function to the “Tyvec” or Housewrap being installed in new homes, beneath the siding.

As far as concerns or drawbacks with application of elastomeric coatings, there may be little other than those associated with any other finish. Proper preparation of the surface to be coated is essential for a good job. The stucco must be in good condition and not damaged or soft. If painted, the old material must have loose, flaking, or chalking areas removed before proceeding. Pressure washing of the old stucco should be done to remove dirt, moss, mould and loose paint that may prevent proper adhesion of the new finish.

The new coating may be applied by a competent homeowner with roller and brush, but should be professionally done if sprayed. As always, obtain several quotes for work, if hiring a contractor, and make certain you are comparing apples to apples. Prices may vary considerably based on level of preparation and experience of the painters. Ask for references and homes in the area that have been done, so you can do a walk-by visual inspection before signing a contract.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the president of the Canadian Association of Home & Property Inspectors — Manitoba (www.cahi.mb.ca). Questions can be e-mailed or sent to: Ask The Inspector, P. O. Box 69021, #110-2025 Corydon Ave., Winnipeg, MB. R3P 2G9. Ari can be reached at (204) 291-5358.

trainedeye@iname.com