Cedar bleed or bleeding of the tannins in the wood, is one of the most common problems we experience in the residential painting business. Cedar bleed occurs when the natural tannins in the wood are drawn to the surface and deposited on the exterior face of the substrate. These tannins are often observed as a reddish-brown discoloration. Moisture is the primary vehicle for the tannins being leeched to the exterior of the substrate. The natural breathing of the building combined with the evaporation process facilitates this whole process. The bleeding is often increased and made more noticeable by other moisture problems such as improper venting, insufficient caulking or flashing, leaks, and other situations that allow moisture to get into or behind the wood.
Cedar is a very common type of clapboard and shingle siding utilized in the construction of homes and condominium buildings. It is an excellent product for this use. Cedar resists decay and can last for decades when properly maintained. Unfortunately, many of the structures that were built with cedar siding in the last twenty + years were sided with inferior wood. The use of inferior types of siding and trim is usually a result of trying to cut corners to build at the lowest possible costs. The current building owners usually realize that they would have been better off paying slightly more for a better product up front.
In other situations, high quality cedar siding was installed in a way that
resulted in premature deterioration and associated failures. Construction
techniques that diminish the quality of the cedar siding include:
• Installing cedar that was not allowed to cure properly before being put into service;
• Installing cedar that was not pre-primed on all edges (including cut ends) prior to being put into service;
• Use of nails other than stainless steel ring shank fasteners; and
• Lack of proper flashing and water infiltration prevention resulting in excessive moisture behind the siding.
Home owners are now paying the penalty for these strategies. Cedar bleed is perhaps the most visible of the problems that are cropping up. Due to its high visibility, cedar bleed can often be the symptom that alerts associations and their contractors to a greater problem.
In order to be able to act in the face of this problem, associations and home owners must realize that a paint job cannot cause cedar bleed any more than it can completely cure it. To cure or eliminate cedar bleed you would have to eliminate the wood itself. Fortunately, however, steps can be taken to alleviate the cedar bleed. There are now stain blocking primers on the market that will effectively reduce the cedar bleed. Some premium products including Woodscapes by Sherwin-Williams provides stain-blocking qualities in two-coat applications.
Preventative maintenance is the key to controlling cedar bleed. Recommendations that are useful in the maintenance of your cedar siding are as follows:
1. Whenever possible, use the best available materials including pre-primed
(and pre-finished if possible) clear vertical grain (CVG) cedar clapboards.
Make sure the siding is installed properly including priming of cut ends,
proper flashing, and the use of the correct fasteners.
2. Power wash thoroughly
3. Allow the property to dry completely after power washing (5-10 days)
4. Caulk any areas on and around the trim that might allow moisture into the substrate (note that areas between clapboards and trim may need to be left open to allow proper breathing/moisture escape).
5. Make sure there is proper venting and flashing in the soffits, siding and roof.
6. Apply one full coat of oil base stain stopper primer and one coat of 100% acrylic solid stain OR
7. Apply two full coats of a premium stain-blocking 100% acrylic solid stain such as Woodscapes by Sherwin-Williams.