Wax Bleeding On Hardboard Siding

One cause of discoloration seen on painted hardboard siding is wax bleeding.  Used while manufacturing hardboard siding, wax or petroleum make a board more moisture resistant.  But under certain conditions, the wax can migrate to the surface of the painted board.  Once on the surface, the wax can change the appearance of the board with a wetting effect.  Another cause comes from the surface wax retaining dirt, thereby affecting the appearance of the painted surface.

Some contributing factors are:

The was in the board is more mobile at high temperatures, so dark colour paints tend to exhibit more discoloration because of their tendency to absorb heat.

Areas with inadequate coats of paint are more likely to stain because was bleeding is seen more readily in the thin areas of the brushed or rolled surface.

Paints containing low levels of binder or a non-volatile vehicle are more porous, and are therefore more likely to allow wax migration from the hardboard.

Southern and western exposured are often subjected to direct sunlight; when a surface becomes hot, it accelerates wax bleeding.

In order to correct discoloration, wax bleeding must be identified as the problem.  Some identification methods include:

Wax is not affected by household bleach.  To test this, place a few drops of bleach on the discolored area.  If there is no whitening or bleaching, the stain is probably wax.

Place water droplets on both normal and discolored areas.  If the water beads up and runs off, a wax film is likely.

In sever cases, the wax may be felt as an oily substance.

When cleaning, if surface wax is light or moderate, areas of discoloration can be cleaned with a detergent solutions.  In sever cases, the surface must be cleaned thoroughly with a solvent such as mineral spirits.  The rags should be changed frequently and the surface allowed to dry before painting

When repainting after cleaing, the surface should be primed with an oxidative primer and topcoated as recommended above.

According to Rick Anderson of Vancouver’s Best Painters, painters painting in Vancouver area in BC, British Columbia www.vancoversbestpainters.com and www.vancouverindustrialpainting.com Vancouver Industrial Painters painting in Vancouver alongside 604-PAINTERS of www.604painters.com and Canadas bes painters located at www.canadasbestpainters.com the solution for Wax Bleeding is as follows:

Early painting prevents discoloration.  Unprimed boards should be primed or painted within 30 days.  Factory-primed boards should be painted within 90 days of installation.  The proper amount of paint will minimize problems.  On unprimed hardboard, apply a primer and two topcoats.  Factory primed hardboard may need to be re-primed and then have two topcoats applied.  Paints should be applied at the spreading rate recommended by the manufacturer.

The type of paint selected is critical to achieving good performance.  On unprimed hardboard,use a good quality, oxidative cure primer (such as alkyd or oil).  The topcoat should be first quality and contain sufficient binder to form a tight uniform film.  It may be oi or latex based.  Stains and or shingle and shake paints should not be used on hardboard.  Paints that are specially formulated for hardboard are recommended.  Always apply two topcoats over factory primed hardboard.

Rick Anderson www.vancouversbestpainters.com