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We Used Extira To Construct Exterior Columns

Eastview Homes’ exterior renovations with natural wood siding typically includes a front entrance make-over with a covered porch and three or four stately wooden pillars, often painted white. The stylish little detail gives the property more self-respect. It dramatically improves curb appeal and probably adds thirty thousand dollars to the value of the house. Now the builders are giving blog readers an inside look at how they’ve just tried a new waterproof building product called Extira to make those uprights during a recent full-house renovation in Burlington.

front column of portico made with MDF

Medium-density fiberboard (MDF) is a hybrid wood product composed of wood fibers bound with wax and resin. The wood paste is formed into 4×8 panels by applying heat and pressure in a factory setting. The result is a really strong building product that’s much denser than particle board, and even denser than some types of plywood, although it doesn’t have the tensile strength of plywood. MDF is commonly painted to mimic other substances like iron and stone, yet one of the most significant drawbacks of MDF has always been its vulnerability to water.

Extira logo on waterproof MDF panel

It has been interesting to watch the development of the engineered wood industry and to track the continuous improvement of these products. Moisture resistant MDF, made from a synthetic glue was the next evolution, and now the Jeld-Wen company’s R&D team has brought a waterproof wood panel to market.

Extira wood panels are engineered for outdoor use. Made with the same proprietary TEC™ process that Jeld-Wen uses to make their waterproof trim product, Extira is a building material made for exterior applications that performs better than wood or MDF. Extira panels may look like MDF, but they can be used outside and won’t deteriorate over time.

Extira is easy to work with. It can be carved, routed and machined. It resists moisture, rot, and termites. It’s twice as strong as MDF, and most importantly, Extira is made for outdoor applications. Builders at Eastview Homes like to use this waterproof material to make foot thick columns which will be painted white (or the same colour as the siding) to give stately presence to the front entrance porticos as part of our exterior home renovations.

Below is just such a scenario; an exterior renovation boasts a new front porch with four pillars. Two of the uprights have been widened with Extira boards affixed to wooden scabbing at the top and bottom. Two more posts await the same treatment.

Regular MDF should never be used outside or anywhere it can get wet as the panels would soon decompose if exposed to rain, wind, and weather. But there are approved methods that contractors can use to ‘waterproof’ regular MDF so the material can better withstand moisture and extreme temperatures. To work with MDF outside however, the easiest solution is to select moisture resistant fiberboard or MR- MDF, and now Extira.

Extira MDF - air gap between panel and concrete to protect against water damage

It should be noted that MR – MDF is moisture-resistant, not water-resistant, or waterproof. The material is still prone to swelling and warping if it gets waterlogged. Even though we are using Extira, we take no chances and that’s why the pillar-boards are screwed into the scabbing one inch above the concrete. This gap will be trimmed over, and the PVC trim can easily be replaced when the porch is repainted.

VERSATEX is our favourite cellular PVC trim. We use their beadboard, corners, and trim boards. VERSATEX offers two finishes, Smooth Matte and Timber Ridge, which is a faux raw-wood texture, as though rough lumber were painted. To be specific, their PVC trim boards can be ordered either Smooth / Smooth or Smooth / Timber Ridge.

These porch pillars will be further improved by Eastview Homes staff members adding additional waterproofing, a latex paint primer, or a primer coat specifically designed for use on MDF. We’ll use a 3/8’s inch paint roller to apply the primer, and a paintbrush to cover any areas that can’t otherwise be reached. The primer will dry for six hours, or overnight, and then we’ll apply a moisture sealant or water-resistant paint with roller and brush. This layer is applied in the morning because we know it’ll take about five hours to dry. Then we apply another layer of waterproof paint in the afternoon, and another the next morning until everything looks superb.

Eastview Also Uses Moisture Resistant MDF

Moisture proof MDF uses a different non water soluble glue which makes it appear green.

In other applications such as bathroom and kitchens and in boiler room, Eastview Homes may utilize Moisture Resistant MDF. We source this material through our suppliers, but the product is available to the public in most big box lumber stores. It’s important to remember that MR – MDF should still be sealed, primed and painted on all surfaces before installation. Readers should not come away believing the material is entirely waterproof.

Most MR-MDF has a greenish hue which indicates the use of a phenol-formaldehyde glue which is a non-soluble resin.

Regular MDF is created using urea-formaldehyde glue. . Urea formaldehyde was first made in 1896 by condensing urea with formaldehyde to form a water-soluble resin which was patented as a molding powder called Pollapas in 1923. This type of glue is inexpensive to purchase and is one reason why normal MDF is so affordable, but unfortunately this binder is also relatively water soluble and offers limited moisture resistance. 

MR – MDF is medium density fiberboard manufactured with phenol-formaldehyde glue. This adhesive resins bonds with the phenol-like lignin which is a natural component of wood. This product is harder to source because the glue is more expensive. It’s the glue’s quality which sets the price, and the product’s moisture-resistant properties will make it worth the investment. An interesting side note, most new billiards balls are also composed of phenol-formaldehyde plastics.

Gluing Extira, or any MR- MDF on Exterior Surfaces

Working with moisture proof MDF means using non water soluble, aliphatic Carpenter's glue

When working with Extira or MR- MDF outside, for any project related to exterior finishes like white pillars on front porches, builders should use yellow glue rather than white glue.

The white glue in your toolkit is most likely melamine glue, a water-based adhesive that is nonflammable. This has low odor, dries clear and cleans up with water.  Melamine glues are designed to bond wood, particle board, MDF and other porous substrates to synthetic materials such as vinyl and high pressure laminate; its a water-soluble adhesive.

The yellow glue is likely aliphatic resin glue which is usually sold in plastic squeeze bottles and often labeled as Carpenters’ glue. Yellow glue is very similar to white glue but forms a slightly stronger bond. It is also more water resistant than white glue.

New Materials Help Renovators Redefine What’s Possible

In summary, it’s an exciting time to be a home renovator as new building materials are constantly appearing and begging to be used. These new engineered woods, stronger beams and improved cement help Eastview Homes push the envelope of what’s possible and set new standards of excellence in Mississauga, Oakville, and Burlington home renovations.   

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