We installed cedar siding on our home about 7 years ago.  We went the extra to have all the siding, trim etc backprimed, prior to being installed.  The exterior finish was 2 coats of Cabot’s semi-solid stain in white, to give a whitewashed appearance without the heavy appearance of a solid stain or paint.  Our area is in northern Michigan and on a lake, so in the summer months, humidity is sometimes an issue.  We do NOT have air conditioning, so I do not believe there is any impact from the interior air temperatures / condensation. For the past three seasons, especially in the fall, mildew has formed on the south, east and west sides of the siding – but not on the north.  We have washed the siding with a bleach solution and recoated, but the mildew reappears within two years and is extremely unsightly.  This has occurred on the house, and also on the adjacent separate garage structure.

We are ready to clean and scrub the siding ‘again’ this spring with a solution of bleach etc to remove the mildew, but would like to know, what should we refinish the siding with ?  My research through coating manufacturers and other web sources has shown that a coating with an acrylic stain would be more desireable than a linseed based stain product, plus a coat or two of a clear acrylic waterproofing (such as TWC).  Is this a good approach and are there any suggestions from some experts in coating out there ?  We would like to see what others have experienced before we try again.

Appreciate the assistance. as we are ‘frustrated’ with the midew look.  Thanks.